storage.go

appservice/storage/cosmosdb/appservice_events_table.go

@@ -0,0 +1,267 @@
+// Copyright 2018 New Vector Ltd
+// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+	"encoding/json"
+	"time"
+
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/gomatrixserverlib"
+	log "github.com/sirupsen/logrus"
+)
+
+const appserviceEventsSchema = `
+-- Stores events to be sent to application services
+CREATE TABLE IF NOT EXISTS appservice_events (
+	-- An auto-incrementing id unique to each event in the table
+	id INTEGER PRIMARY KEY AUTOINCREMENT,
+	-- The ID of the application service the event will be sent to
+	as_id TEXT NOT NULL,
+	-- JSON representation of the event
+	headered_event_json TEXT NOT NULL,
+	-- The ID of the transaction that this event is a part of
+	txn_id INTEGER NOT NULL
+);
+
+CREATE INDEX IF NOT EXISTS appservice_events_as_id ON appservice_events(as_id);
+`
+
+const selectEventsByApplicationServiceIDSQL = "" +
+	"SELECT id, headered_event_json, txn_id " +
+	"FROM appservice_events WHERE as_id = $1 ORDER BY txn_id DESC, id ASC"
+
+const countEventsByApplicationServiceIDSQL = "" +
+	"SELECT COUNT(id) FROM appservice_events WHERE as_id = $1"
+
+const insertEventSQL = "" +
+	"INSERT INTO appservice_events(as_id, headered_event_json, txn_id) " +
+	"VALUES ($1, $2, $3)"
+
+const updateTxnIDForEventsSQL = "" +
+	"UPDATE appservice_events SET txn_id = $1 WHERE as_id = $2 AND id <= $3"
+
+const deleteEventsBeforeAndIncludingIDSQL = "" +
+	"DELETE FROM appservice_events WHERE as_id = $1 AND id <= $2"
+
+const (
+	// A transaction ID number that no transaction should ever have. Used for
+	// checking again the default value.
+	invalidTxnID = -2
+)
+
+type eventsStatements struct {
+	db                                     *sql.DB
+	writer                                 sqlutil.Writer
+	selectEventsByApplicationServiceIDStmt *sql.Stmt
+	countEventsByApplicationServiceIDStmt  *sql.Stmt
+	insertEventStmt                        *sql.Stmt
+	updateTxnIDForEventsStmt               *sql.Stmt
+	deleteEventsBeforeAndIncludingIDStmt   *sql.Stmt
+}
+
+func (s *eventsStatements) prepare(db *sql.DB, writer sqlutil.Writer) (err error) {
+	s.db = db
+	s.writer = writer
+	_, err = db.Exec(appserviceEventsSchema)
+	if err != nil {
+		return
+	}
+
+	if s.selectEventsByApplicationServiceIDStmt, err = db.Prepare(selectEventsByApplicationServiceIDSQL); err != nil {
+		return
+	}
+	if s.countEventsByApplicationServiceIDStmt, err = db.Prepare(countEventsByApplicationServiceIDSQL); err != nil {
+		return
+	}
+	if s.insertEventStmt, err = db.Prepare(insertEventSQL); err != nil {
+		return
+	}
+	if s.updateTxnIDForEventsStmt, err = db.Prepare(updateTxnIDForEventsSQL); err != nil {
+		return
+	}
+	if s.deleteEventsBeforeAndIncludingIDStmt, err = db.Prepare(deleteEventsBeforeAndIncludingIDSQL); err != nil {
+		return
+	}
+
+	return
+}
+
+// selectEventsByApplicationServiceID takes in an application service ID and
+// returns a slice of events that need to be sent to that application service,
+// as well as an int later used to remove these same events from the database
+// once successfully sent to an application service.
+func (s *eventsStatements) selectEventsByApplicationServiceID(
+	ctx context.Context,
+	applicationServiceID string,
+	limit int,
+) (
+	txnID, maxID int,
+	events []gomatrixserverlib.HeaderedEvent,
+	eventsRemaining bool,
+	err error,
+) {
+	defer func() {
+		if err != nil {
+			log.WithFields(log.Fields{
+				"appservice": applicationServiceID,
+			}).WithError(err).Fatalf("appservice unable to select new events to send")
+		}
+	}()
+	// Retrieve events from the database. Unsuccessfully sent events first
+	eventRows, err := s.selectEventsByApplicationServiceIDStmt.QueryContext(ctx, applicationServiceID)
+	if err != nil {
+		return
+	}
+	defer checkNamedErr(eventRows.Close, &err)
+	events, maxID, txnID, eventsRemaining, err = retrieveEvents(eventRows, limit)
+	if err != nil {
+		return
+	}
+
+	return
+}
+
+// checkNamedErr calls fn and overwrite err if it was nil and fn returned non-nil
+func checkNamedErr(fn func() error, err *error) {
+	if e := fn(); e != nil && *err == nil {
+		*err = e
+	}
+}
+
+func retrieveEvents(eventRows *sql.Rows, limit int) (events []gomatrixserverlib.HeaderedEvent, maxID, txnID int, eventsRemaining bool, err error) {
+	// Get current time for use in calculating event age
+	nowMilli := time.Now().UnixNano() / int64(time.Millisecond)
+
+	// Iterate through each row and store event contents
+	// If txn_id changes dramatically, we've switched from collecting old events to
+	// new ones. Send back those events first.
+	lastTxnID := invalidTxnID
+	for eventsProcessed := 0; eventRows.Next(); {
+		var event gomatrixserverlib.HeaderedEvent
+		var eventJSON []byte
+		var id int
+		err = eventRows.Scan(
+			&id,
+			&eventJSON,
+			&txnID,
+		)
+		if err != nil {
+			return nil, 0, 0, false, err
+		}
+
+		// Unmarshal eventJSON
+		if err = json.Unmarshal(eventJSON, &event); err != nil {
+			return nil, 0, 0, false, err
+		}
+
+		// If txnID has changed on this event from the previous event, then we've
+		// reached the end of a transaction's events. Return only those events.
+		if lastTxnID > invalidTxnID && lastTxnID != txnID {
+			return events, maxID, lastTxnID, true, nil
+		}
+		lastTxnID = txnID
+
+		// Limit events that aren't part of an old transaction
+		if txnID == -1 {
+			// Return if we've hit the limit
+			if eventsProcessed++; eventsProcessed > limit {
+				return events, maxID, lastTxnID, true, nil
+			}
+		}
+
+		if id > maxID {
+			maxID = id
+		}
+
+		// Portion of the event that is unsigned due to rapid change
+		// TODO: Consider removing age as not many app services use it
+		if err = event.SetUnsignedField("age", nowMilli-int64(event.OriginServerTS())); err != nil {
+			return nil, 0, 0, false, err
+		}
+
+		events = append(events, event)
+	}
+
+	return
+}
+
+// countEventsByApplicationServiceID inserts an event mapped to its corresponding application service
+// IDs into the db.
+func (s *eventsStatements) countEventsByApplicationServiceID(
+	ctx context.Context,
+	appServiceID string,
+) (int, error) {
+	var count int
+	err := s.countEventsByApplicationServiceIDStmt.QueryRowContext(ctx, appServiceID).Scan(&count)
+	if err != nil && err != sql.ErrNoRows {
+		return 0, err
+	}
+
+	return count, nil
+}
+
+// insertEvent inserts an event mapped to its corresponding application service
+// IDs into the db.
+func (s *eventsStatements) insertEvent(
+	ctx context.Context,
+	appServiceID string,
+	event *gomatrixserverlib.HeaderedEvent,
+) (err error) {
+	// Convert event to JSON before inserting
+	eventJSON, err := json.Marshal(event)
+	if err != nil {
+		return err
+	}
+
+	return s.writer.Do(s.db, nil, func(txn *sql.Tx) error {
+		_, err := s.insertEventStmt.ExecContext(
+			ctx,
+			appServiceID,
+			eventJSON,
+			-1, // No transaction ID yet
+		)
+		return err
+	})
+}
+
+// updateTxnIDForEvents sets the transactionID for a collection of events. Done
+// before sending them to an AppService. Referenced before sending to make sure
+// we aren't constructing multiple transactions with the same events.
+func (s *eventsStatements) updateTxnIDForEvents(
+	ctx context.Context,
+	appserviceID string,
+	maxID, txnID int,
+) (err error) {
+	return s.writer.Do(s.db, nil, func(txn *sql.Tx) error {
+		_, err := s.updateTxnIDForEventsStmt.ExecContext(ctx, txnID, appserviceID, maxID)
+		return err
+	})
+}
+
+// deleteEventsBeforeAndIncludingID removes events matching given IDs from the database.
+func (s *eventsStatements) deleteEventsBeforeAndIncludingID(
+	ctx context.Context,
+	appserviceID string,
+	eventTableID int,
+) (err error) {
+	return s.writer.Do(s.db, nil, func(txn *sql.Tx) error {
+		_, err := s.deleteEventsBeforeAndIncludingIDStmt.ExecContext(ctx, appserviceID, eventTableID)
+		return err
+	})
+}

appservice/storage/cosmosdb/storage.go

@@ -0,0 +1,119 @@
+// Copyright 2018 New Vector Ltd
+// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+
+	// Import SQLite database driver
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/setup/config"
+	"github.com/matrix-org/gomatrixserverlib"
+	_ "github.com/mattn/go-sqlite3"
+)
+
+// Database stores events intended to be later sent to application services
+type Database struct {
+	sqlutil.PartitionOffsetStatements
+	events eventsStatements
+	txnID  txnStatements
+	db     *sql.DB
+	writer sqlutil.Writer
+}
+
+// NewDatabase opens a new database
+func NewDatabase(dbProperties *config.DatabaseOptions) (*Database, error) {
+	var result Database
+	var err error
+	if result.db, err = sqlutil.Open(dbProperties); err != nil {
+		return nil, err
+	}
+	result.writer = sqlutil.NewExclusiveWriter()
+	if err = result.prepare(); err != nil {
+		return nil, err
+	}
+	if err = result.PartitionOffsetStatements.Prepare(result.db, result.writer, "appservice"); err != nil {
+		return nil, err
+	}
+	return &result, nil
+}
+
+func (d *Database) prepare() error {
+	if err := d.events.prepare(d.db, d.writer); err != nil {
+		return err
+	}
+
+	return d.txnID.prepare(d.db, d.writer)
+}
+
+// StoreEvent takes in a gomatrixserverlib.HeaderedEvent and stores it in the database
+// for a transaction worker to pull and later send to an application service.
+func (d *Database) StoreEvent(
+	ctx context.Context,
+	appServiceID string,
+	event *gomatrixserverlib.HeaderedEvent,
+) error {
+	return d.events.insertEvent(ctx, appServiceID, event)
+}
+
+// GetEventsWithAppServiceID returns a slice of events and their IDs intended to
+// be sent to an application service given its ID.
+func (d *Database) GetEventsWithAppServiceID(
+	ctx context.Context,
+	appServiceID string,
+	limit int,
+) (int, int, []gomatrixserverlib.HeaderedEvent, bool, error) {
+	return d.events.selectEventsByApplicationServiceID(ctx, appServiceID, limit)
+}
+
+// CountEventsWithAppServiceID returns the number of events destined for an
+// application service given its ID.
+func (d *Database) CountEventsWithAppServiceID(
+	ctx context.Context,
+	appServiceID string,
+) (int, error) {
+	return d.events.countEventsByApplicationServiceID(ctx, appServiceID)
+}
+
+// UpdateTxnIDForEvents takes in an application service ID and a
+// and stores them in the DB, unless the pair already exists, in
+// which case it updates them.
+func (d *Database) UpdateTxnIDForEvents(
+	ctx context.Context,
+	appserviceID string,
+	maxID, txnID int,
+) error {
+	return d.events.updateTxnIDForEvents(ctx, appserviceID, maxID, txnID)
+}
+
+// RemoveEventsBeforeAndIncludingID removes all events from the database that
+// are less than or equal to a given maximum ID. IDs here are implemented as a
+// serial, thus this should always delete events in chronological order.
+func (d *Database) RemoveEventsBeforeAndIncludingID(
+	ctx context.Context,
+	appserviceID string,
+	eventTableID int,
+) error {
+	return d.events.deleteEventsBeforeAndIncludingID(ctx, appserviceID, eventTableID)
+}
+
+// GetLatestTxnID returns the latest available transaction id
+func (d *Database) GetLatestTxnID(
+	ctx context.Context,
+) (int, error) {
+	return d.txnID.selectTxnID(ctx)
+}

appservice/storage/cosmosdb/txn_id_counter_table.go

@@ -0,0 +1,69 @@
+// Copyright 2018 New Vector Ltd
+// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+)
+
+const txnIDSchema = `
+-- Keeps a count of the current transaction ID
+CREATE TABLE IF NOT EXISTS appservice_counters (
+  name TEXT PRIMARY KEY NOT NULL,
+  last_id INTEGER DEFAULT 1
+);
+INSERT OR IGNORE INTO appservice_counters (name, last_id) VALUES('txn_id', 1);
+`
+
+const selectTxnIDSQL = `
+  SELECT last_id FROM appservice_counters WHERE name='txn_id';
+  UPDATE appservice_counters SET last_id=last_id+1 WHERE name='txn_id';
+`
+
+type txnStatements struct {
+	db              *sql.DB
+	writer          sqlutil.Writer
+	selectTxnIDStmt *sql.Stmt
+}
+
+func (s *txnStatements) prepare(db *sql.DB, writer sqlutil.Writer) (err error) {
+	s.db = db
+	s.writer = writer
+	_, err = db.Exec(txnIDSchema)
+	if err != nil {
+		return
+	}
+
+	if s.selectTxnIDStmt, err = db.Prepare(selectTxnIDSQL); err != nil {
+		return
+	}
+
+	return
+}
+
+// selectTxnID selects the latest ascending transaction ID
+func (s *txnStatements) selectTxnID(
+	ctx context.Context,
+) (txnID int, err error) {
+	err = s.writer.Do(s.db, nil, func(txn *sql.Tx) error {
+		err := s.selectTxnIDStmt.QueryRowContext(ctx).Scan(&txnID)
+		return err
+	})
+	return
+}

appservice/storage/storage.go

@@ -17,6 +17,7 @@
 package storage
 
 import (
+	"github.com/matrix-org/dendrite/appservice/storage/cosmosdb"
 	"fmt"
 
 	"github.com/matrix-org/dendrite/appservice/storage/postgres"
@@ -28,6 +29,8 @@ import (
 // and sets DB connection parameters
 func NewDatabase(dbProperties *config.DatabaseOptions) (Database, error) {
 	switch {
+	case dbProperties.ConnectionString.IsCosmosDB():
+		return cosmosdb.NewDatabase(dbProperties)
 	case dbProperties.ConnectionString.IsSQLite():
 		return sqlite3.NewDatabase(dbProperties)
 	case dbProperties.ConnectionString.IsPostgres():

appservice/storage/storage_wasm.go

@@ -23,6 +23,8 @@ import (
 
 func NewDatabase(dbProperties *config.DatabaseOptions) (Database, error) {
 	switch {
+	case dbProperties.ConnectionString.IsCosmosDB():
+		return nil, fmt.Errorf("can't use CosmosDB implementation")
 	case dbProperties.ConnectionString.IsSQLite():
 		return sqlite3.NewDatabase(dbProperties)
 	case dbProperties.ConnectionString.IsPostgres():

dendrite-config-cosmosdb.yaml

@@ -0,0 +1,394 @@
+# This is the Dendrite configuration file.
+#
+# The configuration is split up into sections - each Dendrite component has a
+# configuration section, in addition to the "global" section which applies to
+# all components.
+#
+# At a minimum, to get started, you will need to update the settings in the
+# "global" section for your deployment, and you will need to check that the
+# database "connection_string" line in each component section is correct. 
+#
+# Each component with a "database" section can accept the following formats
+# for "connection_string":
+#   SQLite:     file:filename.db
+#               file:///path/to/filename.db
+#   PostgreSQL: postgresql://user:pass@hostname/database?params=...
+#   CosmosDB:   cosmosdb:filename.db
+#               cosmosdb:///path/to/filename.db
+#
+# SQLite is embedded into Dendrite and therefore no further prerequisites are
+# needed for the database when using SQLite mode. However, performance with
+# PostgreSQL is significantly better and recommended for multi-user deployments.
+# SQLite is typically around 20-30% slower than PostgreSQL when tested with a
+# small number of users and likely will perform worse still with a higher volume
+# of users.
+#
+# The "max_open_conns" and "max_idle_conns" settings configure the maximum 
+# number of open/idle database connections. The value 0 will use the database
+# engine default, and a negative value will use unlimited connections. The
+# "conn_max_lifetime" option controls the maximum length of time a database
+# connection can be idle in seconds - a negative value is unlimited.
+
+# The version of the configuration file. 
+version: 1
+
+# Global Matrix configuration. This configuration applies to all components.
+global:
+  # The domain name of this homeserver.
+  server_name: localhost
+
+  # The path to the signing private key file, used to sign requests and events.
+  # Note that this is NOT the same private key as used for TLS! To generate a
+  # signing key, use "./bin/generate-keys --private-key matrix_key.pem".
+  private_key: matrix_key.pem
+
+  # The paths and expiry timestamps (as a UNIX timestamp in millisecond precision)
+  # to old signing private keys that were formerly in use on this domain. These
+  # keys will not be used for federation request or event signing, but will be
+  # provided to any other homeserver that asks when trying to verify old events.
+  # old_private_keys:
+  # - private_key: old_matrix_key.pem
+  #   expired_at: 1601024554498
+
+  # How long a remote server can cache our server signing key before requesting it
+  # again. Increasing this number will reduce the number of requests made by other
+  # servers for our key but increases the period that a compromised key will be
+  # considered valid by other homeservers.
+  key_validity_period: 168h0m0s
+
+  # Lists of domains that the server will trust as identity servers to verify third
+  # party identifiers such as phone numbers and email addresses.
+  trusted_third_party_id_servers:
+  - matrix.org
+  - vector.im
+
+  # Disables federation. Dendrite will not be able to make any outbound HTTP requests
+  # to other servers and the federation API will not be exposed.
+  disable_federation: false
+
+  # Configuration for Kafka/Naffka.
+  kafka:
+    # List of Kafka broker addresses to connect to. This is not needed if using
+    # Naffka in monolith mode.
+    addresses:
+      - localhost:2181
+
+    # The prefix to use for Kafka topic names for this homeserver. Change this only if
+    # you are running more than one Dendrite homeserver on the same Kafka deployment.
+    topic_prefix: Dendrite
+
+    # Whether to use Naffka instead of Kafka. This is only available in monolith
+    # mode, but means that you can run a single-process server without requiring
+    # Kafka.
+    use_naffka: true
+
+    # The max size a Kafka message is allowed to use.
+    # You only need to change this value, if you encounter issues with too large messages.
+    # Must be less than/equal to "max.message.bytes" configured in Kafka.
+    # Defaults to 8388608 bytes.
+    # max_message_bytes: 8388608
+
+    # Naffka database options. Not required when using Kafka.
+    naffka_database:
+      connection_string: cosmosdb:naffka.db
+      max_open_conns: 10
+      max_idle_conns: 2
+      conn_max_lifetime: -1
+
+  # Configuration for Prometheus metric collection.
+  metrics:
+    # Whether or not Prometheus metrics are enabled.
+    enabled: false
+
+    # HTTP basic authentication to protect access to monitoring.
+    basic_auth:
+      username: metrics
+      password: metrics
+
+  # DNS cache options. The DNS cache may reduce the load on DNS servers
+  # if there is no local caching resolver available for use.
+  dns_cache:
+    # Whether or not the DNS cache is enabled.
+    enabled: false
+
+    # Maximum number of entries to hold in the DNS cache, and
+    # for how long those items should be considered valid in seconds.
+    cache_size: 256
+    cache_lifetime: 300
+
+# Configuration for the Appservice API.
+app_service_api:
+  internal_api:
+    listen: http://localhost:7777
+    connect: http://localhost:7777
+  database:
+    connection_string: cosmosdb:appservice.db
+    max_open_conns: 10
+    max_idle_conns: 2
+    conn_max_lifetime: -1
+
+  # Disable the validation of TLS certificates of appservices. This is
+  # not recommended in production since it may allow appservice traffic
+  # to be sent to an unverified endpoint.
+  disable_tls_validation: false
+
+  # Appservice configuration files to load into this homeserver.
+  config_files: []
+
+# Configuration for the Client API.
+client_api:
+  internal_api:
+    listen: http://localhost:7771
+    connect: http://localhost:7771
+  external_api:
+    listen: http://[::]:8071
+
+  # Prevents new users from being able to register on this homeserver, except when
+  # using the registration shared secret below.
+  registration_disabled: false
+
+  # If set, allows registration by anyone who knows the shared secret, regardless of
+  # whether registration is otherwise disabled.
+  registration_shared_secret: ""
+
+  # Whether to require reCAPTCHA for registration.
+  enable_registration_captcha: false
+
+  # Settings for ReCAPTCHA. 
+  recaptcha_public_key: ""
+  recaptcha_private_key: ""
+  recaptcha_bypass_secret: ""
+  recaptcha_siteverify_api: ""
+
+  # TURN server information that this homeserver should send to clients. 
+  turn:
+    turn_user_lifetime: ""
+    turn_uris: []
+    turn_shared_secret: ""
+    turn_username: ""
+    turn_password: ""
+
+  # Settings for rate-limited endpoints. Rate limiting will kick in after the
+  # threshold number of "slots" have been taken by requests from a specific 
+  # host. Each "slot" will be released after the cooloff time in milliseconds.
+  rate_limiting:
+    enabled: true
+    threshold: 5
+    cooloff_ms: 500
+
+# Configuration for the EDU server.
+edu_server:
+  internal_api:
+    listen: http://localhost:7778
+    connect: http://localhost:7778
+
+# Configuration for the Federation API.
+federation_api:
+  internal_api:
+    listen: http://localhost:7772
+    connect: http://localhost:7772
+  external_api:
+    listen: http://[::]:8072
+
+  # List of paths to X.509 certificates to be used by the external federation listeners.
+  # These certificates will be used to calculate the TLS fingerprints and other servers
+  # will expect the certificate to match these fingerprints. Certificates must be in PEM
+  # format.
+  federation_certificates: []
+
+# Configuration for the Federation Sender.
+federation_sender:
+  internal_api:
+    listen: http://localhost:7775
+    connect: http://localhost:7775
+  database:
+    connection_string: cosmosdb:federationsender.db
+    max_open_conns: 10
+    max_idle_conns: 2
+    conn_max_lifetime: -1
+
+  # How many times we will try to resend a failed transaction to a specific server. The
+  # backoff is 2**x seconds, so 1 = 2 seconds, 2 = 4 seconds, 3 = 8 seconds etc.
+  send_max_retries: 16
+
+  # Disable the validation of TLS certificates of remote federated homeservers. Do not
+  # enable this option in production as it presents a security risk!
+  disable_tls_validation: false
+
+  # Use the following proxy server for outbound federation traffic.
+  proxy_outbound:
+    enabled: false
+    protocol: http
+    host: localhost
+    port: 8080
+
+# Configuration for the Key Server (for end-to-end encryption).
+key_server:
+  internal_api:
+    listen: http://localhost:7779
+    connect: http://localhost:7779
+  database:
+    connection_string: cosmosdb:keyserver.db
+    max_open_conns: 10
+    max_idle_conns: 2
+    conn_max_lifetime: -1
+
+# Configuration for the Media API.
+media_api:
+  internal_api:
+    listen: http://localhost:7774
+    connect: http://localhost:7774
+  external_api:
+    listen: http://[::]:8074
+  database:
+    connection_string: cosmosdb:mediaapi.db
+    max_open_conns: 5
+    max_idle_conns: 2
+    conn_max_lifetime: -1
+
+  # Storage path for uploaded media. May be relative or absolute.
+  base_path: ./media_store
+
+  # The maximum allowed file size (in bytes) for media uploads to this homeserver
+  # (0 = unlimited). If using a reverse proxy, ensure it allows requests at
+  # least this large (e.g. client_max_body_size in nginx.)
+  max_file_size_bytes: 10485760
+
+  # Whether to dynamically generate thumbnails if needed.
+  dynamic_thumbnails: false
+
+  # The maximum number of simultaneous thumbnail generators to run.
+  max_thumbnail_generators: 10
+
+  # A list of thumbnail sizes to be generated for media content.
+  thumbnail_sizes:
+  - width: 32
+    height: 32
+    method: crop
+  - width: 96
+    height: 96
+    method: crop
+  - width: 640
+    height: 480
+    method: scale
+
+# Configuration for experimental MSC's
+mscs:
+  # A list of enabled MSC's
+  # Currently valid values are:
+  # - msc2836    (Threading, see https://github.com/matrix-org/matrix-doc/pull/2836)
+  # - msc2946    (Spaces Summary, see https://github.com/matrix-org/matrix-doc/pull/2946)
+  mscs: []
+  database:
+    connection_string: cosmosdb:mscs.db
+    max_open_conns: 5
+    max_idle_conns: 2
+    conn_max_lifetime: -1
+
+# Configuration for the Room Server.
+room_server:
+  internal_api:
+    listen: http://localhost:7770
+    connect: http://localhost:7770
+  database:
+    connection_string: cosmosdb:roomserver.db
+    max_open_conns: 10
+    max_idle_conns: 2
+    conn_max_lifetime: -1
+
+# Configuration for the Signing Key Server (for server signing keys).
+signing_key_server:
+  internal_api:
+    listen: http://localhost:7780
+    connect: http://localhost:7780
+  database:
+    connection_string: cosmosdb:signingkeyserver.db
+    max_open_conns: 10
+    max_idle_conns: 2
+    conn_max_lifetime: -1
+
+  # Perspective keyservers to use as a backup when direct key fetches fail. This may
+  # be required to satisfy key requests for servers that are no longer online when
+  # joining some rooms.
+  key_perspectives:
+  - server_name: matrix.org
+    keys:
+    - key_id: ed25519:auto
+      public_key: Noi6WqcDj0QmPxCNQqgezwTlBKrfqehY1u2FyWP9uYw
+    - key_id: ed25519:a_RXGa
+      public_key: l8Hft5qXKn1vfHrg3p4+W8gELQVo8N13JkluMfmn2sQ
+
+  # This option will control whether Dendrite will prefer to look up keys directly
+  # or whether it should try perspective servers first, using direct fetches as a
+  # last resort.
+  prefer_direct_fetch: false
+
+# Configuration for the Sync API.
+sync_api:
+  internal_api:
+    listen: http://localhost:7773
+    connect: http://localhost:7773
+  external_api:
+    listen: http://[::]:8073
+  database:
+    connection_string: cosmosdb:syncapi.db
+    max_open_conns: 10
+    max_idle_conns: 2
+    conn_max_lifetime: -1
+
+  # This option controls which HTTP header to inspect to find the real remote IP
+  # address of the client. This is likely required if Dendrite is running behind
+  # a reverse proxy server.
+  # real_ip_header: X-Real-IP
+
+# Configuration for the User API.
+user_api:
+  # The cost when hashing passwords on registration/login. Default: 10. Min: 4, Max: 31
+  # See https://pkg.go.dev/golang.org/x/crypto/bcrypt for more information.
+  # Setting this lower makes registration/login consume less CPU resources at the cost of security
+  # should the database be compromised. Setting this higher makes registration/login consume more
+  # CPU resources but makes it harder to brute force password hashes.
+  # This value can be low if performing tests or on embedded Dendrite instances (e.g WASM builds)
+  # bcrypt_cost: 10
+  internal_api:
+    listen: http://localhost:7781
+    connect: http://localhost:7781
+  account_database:
+    connection_string: cosmosdb:userapi_accounts.db
+    max_open_conns: 10
+    max_idle_conns: 2
+    conn_max_lifetime: -1
+  device_database:
+    connection_string: cosmosdb:userapi_devices.db
+    max_open_conns: 10
+    max_idle_conns: 2
+    conn_max_lifetime: -1
+  # The length of time that a token issued for a relying party from 
+  # /_matrix/client/r0/user/{userId}/openid/request_token endpoint
+  # is considered to be valid in milliseconds. 
+  # The default lifetime is 3600000ms (60 minutes).
+  # openid_token_lifetime_ms: 3600000
+
+# Configuration for Opentracing.
+# See https://github.com/matrix-org/dendrite/tree/master/docs/tracing for information on
+# how this works and how to set it up.
+tracing:
+  enabled: false
+  jaeger:
+    serviceName: ""
+    disabled: false
+    rpc_metrics: false
+    tags: []
+    sampler: null
+    reporter: null
+    headers: null
+    baggage_restrictions: null
+    throttler: null
+
+# Logging configuration, in addition to the standard logging that is sent to
+# stdout by Dendrite.
+logging:
+- type: file
+  level: info
+  params:
+    path: ./logs

federationsender/storage/cosmosdb/blacklist_table.go

@@ -0,0 +1,107 @@
+// Copyright 2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/gomatrixserverlib"
+)
+
+const blacklistSchema = `
+CREATE TABLE IF NOT EXISTS federationsender_blacklist (
+    -- The blacklisted server name
+	server_name TEXT NOT NULL,
+	UNIQUE (server_name)
+);
+`
+
+const insertBlacklistSQL = "" +
+	"INSERT INTO federationsender_blacklist (server_name) VALUES ($1)" +
+	" ON CONFLICT DO NOTHING"
+
+const selectBlacklistSQL = "" +
+	"SELECT server_name FROM federationsender_blacklist WHERE server_name = $1"
+
+const deleteBlacklistSQL = "" +
+	"DELETE FROM federationsender_blacklist WHERE server_name = $1"
+
+type blacklistStatements struct {
+	db                  *sql.DB
+	insertBlacklistStmt *sql.Stmt
+	selectBlacklistStmt *sql.Stmt
+	deleteBlacklistStmt *sql.Stmt
+}
+
+func NewSQLiteBlacklistTable(db *sql.DB) (s *blacklistStatements, err error) {
+	s = &blacklistStatements{
+		db: db,
+	}
+	_, err = db.Exec(blacklistSchema)
+	if err != nil {
+		return
+	}
+
+	if s.insertBlacklistStmt, err = db.Prepare(insertBlacklistSQL); err != nil {
+		return
+	}
+	if s.selectBlacklistStmt, err = db.Prepare(selectBlacklistSQL); err != nil {
+		return
+	}
+	if s.deleteBlacklistStmt, err = db.Prepare(deleteBlacklistSQL); err != nil {
+		return
+	}
+	return
+}
+
+// insertRoom inserts the room if it didn't already exist.
+// If the room didn't exist then last_event_id is set to the empty string.
+func (s *blacklistStatements) InsertBlacklist(
+	ctx context.Context, txn *sql.Tx, serverName gomatrixserverlib.ServerName,
+) error {
+	stmt := sqlutil.TxStmt(txn, s.insertBlacklistStmt)
+	_, err := stmt.ExecContext(ctx, serverName)
+	return err
+}
+
+// selectRoomForUpdate locks the row for the room and returns the last_event_id.
+// The row must already exist in the table. Callers can ensure that the row
+// exists by calling insertRoom first.
+func (s *blacklistStatements) SelectBlacklist(
+	ctx context.Context, txn *sql.Tx, serverName gomatrixserverlib.ServerName,
+) (bool, error) {
+	stmt := sqlutil.TxStmt(txn, s.selectBlacklistStmt)
+	res, err := stmt.QueryContext(ctx, serverName)
+	if err != nil {
+		return false, err
+	}
+	defer res.Close() // nolint:errcheck
+	// The query will return the server name if the server is blacklisted, and
+	// will return no rows if not. By calling Next, we find out if a row was
+	// returned or not - we don't care about the value itself.
+	return res.Next(), nil
+}
+
+// updateRoom updates the last_event_id for the room. selectRoomForUpdate should
+// have already been called earlier within the transaction.
+func (s *blacklistStatements) DeleteBlacklist(
+	ctx context.Context, txn *sql.Tx, serverName gomatrixserverlib.ServerName,
+) error {
+	stmt := sqlutil.TxStmt(txn, s.deleteBlacklistStmt)
+	_, err := stmt.ExecContext(ctx, serverName)
+	return err
+}

federationsender/storage/cosmosdb/inbound_peeks_table.go

@@ -0,0 +1,176 @@
+// Copyright 2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+	"time"
+
+	"github.com/matrix-org/dendrite/federationsender/types"
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/gomatrixserverlib"
+)
+
+const inboundPeeksSchema = `
+CREATE TABLE IF NOT EXISTS federationsender_inbound_peeks (
+	room_id TEXT NOT NULL,
+	server_name TEXT NOT NULL,
+	peek_id TEXT NOT NULL,
+    creation_ts INTEGER NOT NULL,
+    renewed_ts INTEGER NOT NULL,
+    renewal_interval INTEGER NOT NULL,
+	UNIQUE (room_id, server_name, peek_id)
+);
+`
+
+const insertInboundPeekSQL = "" +
+	"INSERT INTO federationsender_inbound_peeks (room_id, server_name, peek_id, creation_ts, renewed_ts, renewal_interval) VALUES ($1, $2, $3, $4, $5, $6)"
+
+const selectInboundPeekSQL = "" +
+	"SELECT room_id, server_name, peek_id, creation_ts, renewed_ts, renewal_interval FROM federationsender_inbound_peeks WHERE room_id = $1 and server_name = $2 and peek_id = $3"
+
+const selectInboundPeeksSQL = "" +
+	"SELECT room_id, server_name, peek_id, creation_ts, renewed_ts, renewal_interval FROM federationsender_inbound_peeks WHERE room_id = $1"
+
+const renewInboundPeekSQL = "" +
+	"UPDATE federationsender_inbound_peeks SET renewed_ts=$1, renewal_interval=$2 WHERE room_id = $3 and server_name = $4 and peek_id = $5"
+
+const deleteInboundPeekSQL = "" +
+	"DELETE FROM federationsender_inbound_peeks WHERE room_id = $1 and server_name = $2"
+
+const deleteInboundPeeksSQL = "" +
+	"DELETE FROM federationsender_inbound_peeks WHERE room_id = $1"
+
+type inboundPeeksStatements struct {
+	db                     *sql.DB
+	insertInboundPeekStmt  *sql.Stmt
+	selectInboundPeekStmt  *sql.Stmt
+	selectInboundPeeksStmt *sql.Stmt
+	renewInboundPeekStmt   *sql.Stmt
+	deleteInboundPeekStmt  *sql.Stmt
+	deleteInboundPeeksStmt *sql.Stmt
+}
+
+func NewSQLiteInboundPeeksTable(db *sql.DB) (s *inboundPeeksStatements, err error) {
+	s = &inboundPeeksStatements{
+		db: db,
+	}
+	_, err = db.Exec(inboundPeeksSchema)
+	if err != nil {
+		return
+	}
+
+	if s.insertInboundPeekStmt, err = db.Prepare(insertInboundPeekSQL); err != nil {
+		return
+	}
+	if s.selectInboundPeekStmt, err = db.Prepare(selectInboundPeekSQL); err != nil {
+		return
+	}
+	if s.selectInboundPeeksStmt, err = db.Prepare(selectInboundPeeksSQL); err != nil {
+		return
+	}
+	if s.renewInboundPeekStmt, err = db.Prepare(renewInboundPeekSQL); err != nil {
+		return
+	}
+	if s.deleteInboundPeeksStmt, err = db.Prepare(deleteInboundPeeksSQL); err != nil {
+		return
+	}
+	if s.deleteInboundPeekStmt, err = db.Prepare(deleteInboundPeekSQL); err != nil {
+		return
+	}
+	return
+}
+
+func (s *inboundPeeksStatements) InsertInboundPeek(
+	ctx context.Context, txn *sql.Tx, serverName gomatrixserverlib.ServerName, roomID, peekID string, renewalInterval int64,
+) (err error) {
+	nowMilli := time.Now().UnixNano() / int64(time.Millisecond)
+	stmt := sqlutil.TxStmt(txn, s.insertInboundPeekStmt)
+	_, err = stmt.ExecContext(ctx, roomID, serverName, peekID, nowMilli, nowMilli, renewalInterval)
+	return
+}
+
+func (s *inboundPeeksStatements) RenewInboundPeek(
+	ctx context.Context, txn *sql.Tx, serverName gomatrixserverlib.ServerName, roomID, peekID string, renewalInterval int64,
+) (err error) {
+	nowMilli := time.Now().UnixNano() / int64(time.Millisecond)
+	_, err = sqlutil.TxStmt(txn, s.renewInboundPeekStmt).ExecContext(ctx, nowMilli, renewalInterval, roomID, serverName, peekID)
+	return
+}
+
+func (s *inboundPeeksStatements) SelectInboundPeek(
+	ctx context.Context, txn *sql.Tx, serverName gomatrixserverlib.ServerName, roomID, peekID string,
+) (*types.InboundPeek, error) {
+	row := sqlutil.TxStmt(txn, s.selectInboundPeeksStmt).QueryRowContext(ctx, roomID)
+	inboundPeek := types.InboundPeek{}
+	err := row.Scan(
+		&inboundPeek.RoomID,
+		&inboundPeek.ServerName,
+		&inboundPeek.PeekID,
+		&inboundPeek.CreationTimestamp,
+		&inboundPeek.RenewedTimestamp,
+		&inboundPeek.RenewalInterval,
+	)
+	if err == sql.ErrNoRows {
+		return nil, nil
+	}
+	if err != nil {
+		return nil, err
+	}
+	return &inboundPeek, nil
+}
+
+func (s *inboundPeeksStatements) SelectInboundPeeks(
+	ctx context.Context, txn *sql.Tx, roomID string,
+) (inboundPeeks []types.InboundPeek, err error) {
+	rows, err := sqlutil.TxStmt(txn, s.selectInboundPeeksStmt).QueryContext(ctx, roomID)
+	if err != nil {
+		return
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "SelectInboundPeeks: rows.close() failed")
+
+	for rows.Next() {
+		inboundPeek := types.InboundPeek{}
+		if err = rows.Scan(
+			&inboundPeek.RoomID,
+			&inboundPeek.ServerName,
+			&inboundPeek.PeekID,
+			&inboundPeek.CreationTimestamp,
+			&inboundPeek.RenewedTimestamp,
+			&inboundPeek.RenewalInterval,
+		); err != nil {
+			return
+		}
+		inboundPeeks = append(inboundPeeks, inboundPeek)
+	}
+
+	return inboundPeeks, rows.Err()
+}
+
+func (s *inboundPeeksStatements) DeleteInboundPeek(
+	ctx context.Context, txn *sql.Tx, serverName gomatrixserverlib.ServerName, roomID, peekID string,
+) (err error) {
+	_, err = sqlutil.TxStmt(txn, s.deleteInboundPeekStmt).ExecContext(ctx, roomID, serverName, peekID)
+	return
+}
+
+func (s *inboundPeeksStatements) DeleteInboundPeeks(
+	ctx context.Context, txn *sql.Tx, roomID string,
+) (err error) {
+	_, err = sqlutil.TxStmt(txn, s.deleteInboundPeeksStmt).ExecContext(ctx, roomID)
+	return
+}

federationsender/storage/cosmosdb/joined_hosts_table.go

@@ -0,0 +1,219 @@
+// Copyright 2017-2018 New Vector Ltd
+// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+	"strings"
+
+	"github.com/matrix-org/dendrite/federationsender/types"
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/gomatrixserverlib"
+)
+
+const joinedHostsSchema = `
+-- The joined_hosts table stores a list of m.room.member event ids in the
+-- current state for each room where the membership is "join".
+-- There will be an entry for every user that is joined to the room.
+CREATE TABLE IF NOT EXISTS federationsender_joined_hosts (
+    -- The string ID of the room.
+    room_id TEXT NOT NULL,
+    -- The event ID of the m.room.member join event.
+    event_id TEXT NOT NULL,
+    -- The domain part of the user ID the m.room.member event is for.
+    server_name TEXT NOT NULL
+);
+
+CREATE UNIQUE INDEX IF NOT EXISTS federatonsender_joined_hosts_event_id_idx
+    ON federationsender_joined_hosts (event_id);
+
+CREATE INDEX IF NOT EXISTS federatonsender_joined_hosts_room_id_idx
+    ON federationsender_joined_hosts (room_id)
+`
+
+const insertJoinedHostsSQL = "" +
+	"INSERT OR IGNORE INTO federationsender_joined_hosts (room_id, event_id, server_name)" +
+	" VALUES ($1, $2, $3)"
+
+const deleteJoinedHostsSQL = "" +
+	"DELETE FROM federationsender_joined_hosts WHERE event_id = $1"
+
+const deleteJoinedHostsForRoomSQL = "" +
+	"DELETE FROM federationsender_joined_hosts WHERE room_id = $1"
+
+const selectJoinedHostsSQL = "" +
+	"SELECT event_id, server_name FROM federationsender_joined_hosts" +
+	" WHERE room_id = $1"
+
+const selectAllJoinedHostsSQL = "" +
+	"SELECT DISTINCT server_name FROM federationsender_joined_hosts"
+
+const selectJoinedHostsForRoomsSQL = "" +
+	"SELECT DISTINCT server_name FROM federationsender_joined_hosts WHERE room_id IN ($1)"
+
+type joinedHostsStatements struct {
+	db                           *sql.DB
+	insertJoinedHostsStmt        *sql.Stmt
+	deleteJoinedHostsStmt        *sql.Stmt
+	deleteJoinedHostsForRoomStmt *sql.Stmt
+	selectJoinedHostsStmt        *sql.Stmt
+	selectAllJoinedHostsStmt     *sql.Stmt
+	// selectJoinedHostsForRoomsStmt *sql.Stmt - prepared at runtime due to variadic
+}
+
+func NewSQLiteJoinedHostsTable(db *sql.DB) (s *joinedHostsStatements, err error) {
+	s = &joinedHostsStatements{
+		db: db,
+	}
+	_, err = db.Exec(joinedHostsSchema)
+	if err != nil {
+		return
+	}
+	if s.insertJoinedHostsStmt, err = db.Prepare(insertJoinedHostsSQL); err != nil {
+		return
+	}
+	if s.deleteJoinedHostsStmt, err = db.Prepare(deleteJoinedHostsSQL); err != nil {
+		return
+	}
+	if s.deleteJoinedHostsForRoomStmt, err = s.db.Prepare(deleteJoinedHostsForRoomSQL); err != nil {
+		return
+	}
+	if s.selectJoinedHostsStmt, err = db.Prepare(selectJoinedHostsSQL); err != nil {
+		return
+	}
+	if s.selectAllJoinedHostsStmt, err = db.Prepare(selectAllJoinedHostsSQL); err != nil {
+		return
+	}
+	return
+}
+
+func (s *joinedHostsStatements) InsertJoinedHosts(
+	ctx context.Context,
+	txn *sql.Tx,
+	roomID, eventID string,
+	serverName gomatrixserverlib.ServerName,
+) error {
+	stmt := sqlutil.TxStmt(txn, s.insertJoinedHostsStmt)
+	_, err := stmt.ExecContext(ctx, roomID, eventID, serverName)
+	return err
+}
+
+func (s *joinedHostsStatements) DeleteJoinedHosts(
+	ctx context.Context, txn *sql.Tx, eventIDs []string,
+) error {
+	for _, eventID := range eventIDs {
+		stmt := sqlutil.TxStmt(txn, s.deleteJoinedHostsStmt)
+		if _, err := stmt.ExecContext(ctx, eventID); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (s *joinedHostsStatements) DeleteJoinedHostsForRoom(
+	ctx context.Context, txn *sql.Tx, roomID string,
+) error {
+	stmt := sqlutil.TxStmt(txn, s.deleteJoinedHostsForRoomStmt)
+	_, err := stmt.ExecContext(ctx, roomID)
+	return err
+}
+
+func (s *joinedHostsStatements) SelectJoinedHostsWithTx(
+	ctx context.Context, txn *sql.Tx, roomID string,
+) ([]types.JoinedHost, error) {
+	stmt := sqlutil.TxStmt(txn, s.selectJoinedHostsStmt)
+	return joinedHostsFromStmt(ctx, stmt, roomID)
+}
+
+func (s *joinedHostsStatements) SelectJoinedHosts(
+	ctx context.Context, roomID string,
+) ([]types.JoinedHost, error) {
+	return joinedHostsFromStmt(ctx, s.selectJoinedHostsStmt, roomID)
+}
+
+func (s *joinedHostsStatements) SelectAllJoinedHosts(
+	ctx context.Context,
+) ([]gomatrixserverlib.ServerName, error) {
+	rows, err := s.selectAllJoinedHostsStmt.QueryContext(ctx)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "selectAllJoinedHosts: rows.close() failed")
+
+	var result []gomatrixserverlib.ServerName
+	for rows.Next() {
+		var serverName string
+		if err = rows.Scan(&serverName); err != nil {
+			return nil, err
+		}
+		result = append(result, gomatrixserverlib.ServerName(serverName))
+	}
+
+	return result, rows.Err()
+}
+
+func (s *joinedHostsStatements) SelectJoinedHostsForRooms(
+	ctx context.Context, roomIDs []string,
+) ([]gomatrixserverlib.ServerName, error) {
+	iRoomIDs := make([]interface{}, len(roomIDs))
+	for i := range roomIDs {
+		iRoomIDs[i] = roomIDs[i]
+	}
+
+	sql := strings.Replace(selectJoinedHostsForRoomsSQL, "($1)", sqlutil.QueryVariadic(len(iRoomIDs)), 1)
+	rows, err := s.db.QueryContext(ctx, sql, iRoomIDs...)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "selectJoinedHostsForRoomsStmt: rows.close() failed")
+
+	var result []gomatrixserverlib.ServerName
+	for rows.Next() {
+		var serverName string
+		if err = rows.Scan(&serverName); err != nil {
+			return nil, err
+		}
+		result = append(result, gomatrixserverlib.ServerName(serverName))
+	}
+
+	return result, rows.Err()
+}
+
+func joinedHostsFromStmt(
+	ctx context.Context, stmt *sql.Stmt, roomID string,
+) ([]types.JoinedHost, error) {
+	rows, err := stmt.QueryContext(ctx, roomID)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "joinedHostsFromStmt: rows.close() failed")
+
+	var result []types.JoinedHost
+	for rows.Next() {
+		var eventID, serverName string
+		if err = rows.Scan(&eventID, &serverName); err != nil {
+			return nil, err
+		}
+		result = append(result, types.JoinedHost{
+			MemberEventID: eventID,
+			ServerName:    gomatrixserverlib.ServerName(serverName),
+		})
+	}
+
+	return result, nil
+}

federationsender/storage/cosmosdb/outbound_peeks_table.go

@@ -0,0 +1,176 @@
+// Copyright 2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+	"time"
+
+	"github.com/matrix-org/dendrite/federationsender/types"
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/gomatrixserverlib"
+)
+
+const outboundPeeksSchema = `
+CREATE TABLE IF NOT EXISTS federationsender_outbound_peeks (
+	room_id TEXT NOT NULL,
+	server_name TEXT NOT NULL,
+	peek_id TEXT NOT NULL,
+    creation_ts INTEGER NOT NULL,
+    renewed_ts INTEGER NOT NULL,
+    renewal_interval INTEGER NOT NULL,
+	UNIQUE (room_id, server_name, peek_id)
+);
+`
+
+const insertOutboundPeekSQL = "" +
+	"INSERT INTO federationsender_outbound_peeks (room_id, server_name, peek_id, creation_ts, renewed_ts, renewal_interval) VALUES ($1, $2, $3, $4, $5, $6)"
+
+const selectOutboundPeekSQL = "" +
+	"SELECT room_id, server_name, peek_id, creation_ts, renewed_ts, renewal_interval FROM federationsender_outbound_peeks WHERE room_id = $1 and server_name = $2 and peek_id = $3"
+
+const selectOutboundPeeksSQL = "" +
+	"SELECT room_id, server_name, peek_id, creation_ts, renewed_ts, renewal_interval FROM federationsender_outbound_peeks WHERE room_id = $1"
+
+const renewOutboundPeekSQL = "" +
+	"UPDATE federationsender_outbound_peeks SET renewed_ts=$1, renewal_interval=$2 WHERE room_id = $3 and server_name = $4 and peek_id = $5"
+
+const deleteOutboundPeekSQL = "" +
+	"DELETE FROM federationsender_outbound_peeks WHERE room_id = $1 and server_name = $2"
+
+const deleteOutboundPeeksSQL = "" +
+	"DELETE FROM federationsender_outbound_peeks WHERE room_id = $1"
+
+type outboundPeeksStatements struct {
+	db                      *sql.DB
+	insertOutboundPeekStmt  *sql.Stmt
+	selectOutboundPeekStmt  *sql.Stmt
+	selectOutboundPeeksStmt *sql.Stmt
+	renewOutboundPeekStmt   *sql.Stmt
+	deleteOutboundPeekStmt  *sql.Stmt
+	deleteOutboundPeeksStmt *sql.Stmt
+}
+
+func NewSQLiteOutboundPeeksTable(db *sql.DB) (s *outboundPeeksStatements, err error) {
+	s = &outboundPeeksStatements{
+		db: db,
+	}
+	_, err = db.Exec(outboundPeeksSchema)
+	if err != nil {
+		return
+	}
+
+	if s.insertOutboundPeekStmt, err = db.Prepare(insertOutboundPeekSQL); err != nil {
+		return
+	}
+	if s.selectOutboundPeekStmt, err = db.Prepare(selectOutboundPeekSQL); err != nil {
+		return
+	}
+	if s.selectOutboundPeeksStmt, err = db.Prepare(selectOutboundPeeksSQL); err != nil {
+		return
+	}
+	if s.renewOutboundPeekStmt, err = db.Prepare(renewOutboundPeekSQL); err != nil {
+		return
+	}
+	if s.deleteOutboundPeeksStmt, err = db.Prepare(deleteOutboundPeeksSQL); err != nil {
+		return
+	}
+	if s.deleteOutboundPeekStmt, err = db.Prepare(deleteOutboundPeekSQL); err != nil {
+		return
+	}
+	return
+}
+
+func (s *outboundPeeksStatements) InsertOutboundPeek(
+	ctx context.Context, txn *sql.Tx, serverName gomatrixserverlib.ServerName, roomID, peekID string, renewalInterval int64,
+) (err error) {
+	nowMilli := time.Now().UnixNano() / int64(time.Millisecond)
+	stmt := sqlutil.TxStmt(txn, s.insertOutboundPeekStmt)
+	_, err = stmt.ExecContext(ctx, roomID, serverName, peekID, nowMilli, nowMilli, renewalInterval)
+	return
+}
+
+func (s *outboundPeeksStatements) RenewOutboundPeek(
+	ctx context.Context, txn *sql.Tx, serverName gomatrixserverlib.ServerName, roomID, peekID string, renewalInterval int64,
+) (err error) {
+	nowMilli := time.Now().UnixNano() / int64(time.Millisecond)
+	_, err = sqlutil.TxStmt(txn, s.renewOutboundPeekStmt).ExecContext(ctx, nowMilli, renewalInterval, roomID, serverName, peekID)
+	return
+}
+
+func (s *outboundPeeksStatements) SelectOutboundPeek(
+	ctx context.Context, txn *sql.Tx, serverName gomatrixserverlib.ServerName, roomID, peekID string,
+) (*types.OutboundPeek, error) {
+	row := sqlutil.TxStmt(txn, s.selectOutboundPeeksStmt).QueryRowContext(ctx, roomID)
+	outboundPeek := types.OutboundPeek{}
+	err := row.Scan(
+		&outboundPeek.RoomID,
+		&outboundPeek.ServerName,
+		&outboundPeek.PeekID,
+		&outboundPeek.CreationTimestamp,
+		&outboundPeek.RenewedTimestamp,
+		&outboundPeek.RenewalInterval,
+	)
+	if err == sql.ErrNoRows {
+		return nil, nil
+	}
+	if err != nil {
+		return nil, err
+	}
+	return &outboundPeek, nil
+}
+
+func (s *outboundPeeksStatements) SelectOutboundPeeks(
+	ctx context.Context, txn *sql.Tx, roomID string,
+) (outboundPeeks []types.OutboundPeek, err error) {
+	rows, err := sqlutil.TxStmt(txn, s.selectOutboundPeeksStmt).QueryContext(ctx, roomID)
+	if err != nil {
+		return
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "SelectOutboundPeeks: rows.close() failed")
+
+	for rows.Next() {
+		outboundPeek := types.OutboundPeek{}
+		if err = rows.Scan(
+			&outboundPeek.RoomID,
+			&outboundPeek.ServerName,
+			&outboundPeek.PeekID,
+			&outboundPeek.CreationTimestamp,
+			&outboundPeek.RenewedTimestamp,
+			&outboundPeek.RenewalInterval,
+		); err != nil {
+			return
+		}
+		outboundPeeks = append(outboundPeeks, outboundPeek)
+	}
+
+	return outboundPeeks, rows.Err()
+}
+
+func (s *outboundPeeksStatements) DeleteOutboundPeek(
+	ctx context.Context, txn *sql.Tx, serverName gomatrixserverlib.ServerName, roomID, peekID string,
+) (err error) {
+	_, err = sqlutil.TxStmt(txn, s.deleteOutboundPeekStmt).ExecContext(ctx, roomID, serverName, peekID)
+	return
+}
+
+func (s *outboundPeeksStatements) DeleteOutboundPeeks(
+	ctx context.Context, txn *sql.Tx, roomID string,
+) (err error) {
+	_, err = sqlutil.TxStmt(txn, s.deleteOutboundPeeksStmt).ExecContext(ctx, roomID)
+	return
+}

federationsender/storage/cosmosdb/queue_edus_table.go

@@ -0,0 +1,207 @@
+// Copyright 2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+	"strings"
+
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/gomatrixserverlib"
+)
+
+const queueEDUsSchema = `
+CREATE TABLE IF NOT EXISTS federationsender_queue_edus (
+	-- The type of the event (informational).
+	edu_type TEXT NOT NULL,
+    -- The domain part of the user ID the EDU event is for.
+	server_name TEXT NOT NULL,
+	-- The JSON NID from the federationsender_queue_edus_json table.
+	json_nid BIGINT NOT NULL
+);
+
+CREATE UNIQUE INDEX IF NOT EXISTS federationsender_queue_edus_json_nid_idx
+    ON federationsender_queue_edus (json_nid, server_name);
+`
+
+const insertQueueEDUSQL = "" +
+	"INSERT INTO federationsender_queue_edus (edu_type, server_name, json_nid)" +
+	" VALUES ($1, $2, $3)"
+
+const deleteQueueEDUsSQL = "" +
+	"DELETE FROM federationsender_queue_edus WHERE server_name = $1 AND json_nid IN ($2)"
+
+const selectQueueEDUSQL = "" +
+	"SELECT json_nid FROM federationsender_queue_edus" +
+	" WHERE server_name = $1" +
+	" LIMIT $2"
+
+const selectQueueEDUReferenceJSONCountSQL = "" +
+	"SELECT COUNT(*) FROM federationsender_queue_edus" +
+	" WHERE json_nid = $1"
+
+const selectQueueEDUCountSQL = "" +
+	"SELECT COUNT(*) FROM federationsender_queue_edus" +
+	" WHERE server_name = $1"
+
+const selectQueueServerNamesSQL = "" +
+	"SELECT DISTINCT server_name FROM federationsender_queue_edus"
+
+type queueEDUsStatements struct {
+	db                                   *sql.DB
+	insertQueueEDUStmt                   *sql.Stmt
+	selectQueueEDUStmt                   *sql.Stmt
+	selectQueueEDUReferenceJSONCountStmt *sql.Stmt
+	selectQueueEDUCountStmt              *sql.Stmt
+	selectQueueEDUServerNamesStmt        *sql.Stmt
+}
+
+func NewSQLiteQueueEDUsTable(db *sql.DB) (s *queueEDUsStatements, err error) {
+	s = &queueEDUsStatements{
+		db: db,
+	}
+	_, err = db.Exec(queueEDUsSchema)
+	if err != nil {
+		return
+	}
+	if s.insertQueueEDUStmt, err = db.Prepare(insertQueueEDUSQL); err != nil {
+		return
+	}
+	if s.selectQueueEDUStmt, err = db.Prepare(selectQueueEDUSQL); err != nil {
+		return
+	}
+	if s.selectQueueEDUReferenceJSONCountStmt, err = db.Prepare(selectQueueEDUReferenceJSONCountSQL); err != nil {
+		return
+	}
+	if s.selectQueueEDUCountStmt, err = db.Prepare(selectQueueEDUCountSQL); err != nil {
+		return
+	}
+	if s.selectQueueEDUServerNamesStmt, err = db.Prepare(selectQueueServerNamesSQL); err != nil {
+		return
+	}
+	return
+}
+
+func (s *queueEDUsStatements) InsertQueueEDU(
+	ctx context.Context,
+	txn *sql.Tx,
+	eduType string,
+	serverName gomatrixserverlib.ServerName,
+	nid int64,
+) error {
+	stmt := sqlutil.TxStmt(txn, s.insertQueueEDUStmt)
+	_, err := stmt.ExecContext(
+		ctx,
+		eduType,    // the EDU type
+		serverName, // destination server name
+		nid,        // JSON blob NID
+	)
+	return err
+}
+
+func (s *queueEDUsStatements) DeleteQueueEDUs(
+	ctx context.Context, txn *sql.Tx,
+	serverName gomatrixserverlib.ServerName,
+	jsonNIDs []int64,
+) error {
+	deleteSQL := strings.Replace(deleteQueueEDUsSQL, "($2)", sqlutil.QueryVariadicOffset(len(jsonNIDs), 1), 1)
+	deleteStmt, err := txn.Prepare(deleteSQL)
+	if err != nil {
+		return fmt.Errorf("s.deleteQueueJSON s.db.Prepare: %w", err)
+	}
+
+	params := make([]interface{}, len(jsonNIDs)+1)
+	params[0] = serverName
+	for k, v := range jsonNIDs {
+		params[k+1] = v
+	}
+
+	stmt := sqlutil.TxStmt(txn, deleteStmt)
+	_, err = stmt.ExecContext(ctx, params...)
+	return err
+}
+
+func (s *queueEDUsStatements) SelectQueueEDUs(
+	ctx context.Context, txn *sql.Tx,
+	serverName gomatrixserverlib.ServerName,
+	limit int,
+) ([]int64, error) {
+	stmt := sqlutil.TxStmt(txn, s.selectQueueEDUStmt)
+	rows, err := stmt.QueryContext(ctx, serverName, limit)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "queueFromStmt: rows.close() failed")
+	var result []int64
+	for rows.Next() {
+		var nid int64
+		if err = rows.Scan(&nid); err != nil {
+			return nil, err
+		}
+		result = append(result, nid)
+	}
+	return result, nil
+}
+
+func (s *queueEDUsStatements) SelectQueueEDUReferenceJSONCount(
+	ctx context.Context, txn *sql.Tx, jsonNID int64,
+) (int64, error) {
+	var count int64
+	stmt := sqlutil.TxStmt(txn, s.selectQueueEDUReferenceJSONCountStmt)
+	err := stmt.QueryRowContext(ctx, jsonNID).Scan(&count)
+	if err == sql.ErrNoRows {
+		return -1, nil
+	}
+	return count, err
+}
+
+func (s *queueEDUsStatements) SelectQueueEDUCount(
+	ctx context.Context, txn *sql.Tx, serverName gomatrixserverlib.ServerName,
+) (int64, error) {
+	var count int64
+	stmt := sqlutil.TxStmt(txn, s.selectQueueEDUCountStmt)
+	err := stmt.QueryRowContext(ctx, serverName).Scan(&count)
+	if err == sql.ErrNoRows {
+		// It's acceptable for there to be no rows referencing a given
+		// JSON NID but it's not an error condition. Just return as if
+		// there's a zero count.
+		return 0, nil
+	}
+	return count, err
+}
+
+func (s *queueEDUsStatements) SelectQueueEDUServerNames(
+	ctx context.Context, txn *sql.Tx,
+) ([]gomatrixserverlib.ServerName, error) {
+	stmt := sqlutil.TxStmt(txn, s.selectQueueEDUServerNamesStmt)
+	rows, err := stmt.QueryContext(ctx)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "queueFromStmt: rows.close() failed")
+	var result []gomatrixserverlib.ServerName
+	for rows.Next() {
+		var serverName gomatrixserverlib.ServerName
+		if err = rows.Scan(&serverName); err != nil {
+			return nil, err
+		}
+		result = append(result, serverName)
+	}
+
+	return result, rows.Err()
+}

federationsender/storage/cosmosdb/queue_json_table.go

@@ -0,0 +1,136 @@
+// Copyright 2017-2018 New Vector Ltd
+// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+	"strings"
+
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+)
+
+const queueJSONSchema = `
+-- The queue_retry_json table contains event contents that
+-- we failed to send. 
+CREATE TABLE IF NOT EXISTS federationsender_queue_json (
+	-- The JSON NID. This allows the federationsender_queue_retry table to
+	-- cross-reference to find the JSON blob.
+	json_nid INTEGER PRIMARY KEY AUTOINCREMENT,
+	-- The JSON body. Text so that we preserve UTF-8.
+	json_body TEXT NOT NULL
+);
+`
+
+const insertJSONSQL = "" +
+	"INSERT INTO federationsender_queue_json (json_body)" +
+	" VALUES ($1)"
+
+const deleteJSONSQL = "" +
+	"DELETE FROM federationsender_queue_json WHERE json_nid IN ($1)"
+
+const selectJSONSQL = "" +
+	"SELECT json_nid, json_body FROM federationsender_queue_json" +
+	" WHERE json_nid IN ($1)"
+
+type queueJSONStatements struct {
+	db             *sql.DB
+	insertJSONStmt *sql.Stmt
+	//deleteJSONStmt *sql.Stmt - prepared at runtime due to variadic
+	//selectJSONStmt *sql.Stmt - prepared at runtime due to variadic
+}
+
+func NewSQLiteQueueJSONTable(db *sql.DB) (s *queueJSONStatements, err error) {
+	s = &queueJSONStatements{
+		db: db,
+	}
+	_, err = db.Exec(queueJSONSchema)
+	if err != nil {
+		return
+	}
+	if s.insertJSONStmt, err = db.Prepare(insertJSONSQL); err != nil {
+		return
+	}
+	return
+}
+
+func (s *queueJSONStatements) InsertQueueJSON(
+	ctx context.Context, txn *sql.Tx, json string,
+) (lastid int64, err error) {
+	stmt := sqlutil.TxStmt(txn, s.insertJSONStmt)
+	res, err := stmt.ExecContext(ctx, json)
+	if err != nil {
+		return 0, fmt.Errorf("stmt.QueryContext: %w", err)
+	}
+	lastid, err = res.LastInsertId()
+	if err != nil {
+		return 0, fmt.Errorf("res.LastInsertId: %w", err)
+	}
+	return
+}
+
+func (s *queueJSONStatements) DeleteQueueJSON(
+	ctx context.Context, txn *sql.Tx, nids []int64,
+) error {
+	deleteSQL := strings.Replace(deleteJSONSQL, "($1)", sqlutil.QueryVariadic(len(nids)), 1)
+	deleteStmt, err := txn.Prepare(deleteSQL)
+	if err != nil {
+		return fmt.Errorf("s.deleteQueueJSON s.db.Prepare: %w", err)
+	}
+
+	iNIDs := make([]interface{}, len(nids))
+	for k, v := range nids {
+		iNIDs[k] = v
+	}
+
+	stmt := sqlutil.TxStmt(txn, deleteStmt)
+	_, err = stmt.ExecContext(ctx, iNIDs...)
+	return err
+}
+
+func (s *queueJSONStatements) SelectQueueJSON(
+	ctx context.Context, txn *sql.Tx, jsonNIDs []int64,
+) (map[int64][]byte, error) {
+	selectSQL := strings.Replace(selectJSONSQL, "($1)", sqlutil.QueryVariadic(len(jsonNIDs)), 1)
+	selectStmt, err := txn.Prepare(selectSQL)
+	if err != nil {
+		return nil, fmt.Errorf("s.selectQueueJSON s.db.Prepare: %w", err)
+	}
+
+	iNIDs := make([]interface{}, len(jsonNIDs))
+	for k, v := range jsonNIDs {
+		iNIDs[k] = v
+	}
+
+	blobs := map[int64][]byte{}
+	stmt := sqlutil.TxStmt(txn, selectStmt)
+	rows, err := stmt.QueryContext(ctx, iNIDs...)
+	if err != nil {
+		return nil, fmt.Errorf("s.selectQueueJSON stmt.QueryContext: %w", err)
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "selectJSON: rows.close() failed")
+	for rows.Next() {
+		var nid int64
+		var blob []byte
+		if err = rows.Scan(&nid, &blob); err != nil {
+			return nil, fmt.Errorf("s.selectQueueJSON rows.Scan: %w", err)
+		}
+		blobs[nid] = blob
+	}
+	return blobs, err
+}

federationsender/storage/cosmosdb/queue_pdus_table.go

@@ -0,0 +1,235 @@
+// Copyright 2017-2018 New Vector Ltd
+// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+	"strings"
+
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/gomatrixserverlib"
+)
+
+const queuePDUsSchema = `
+CREATE TABLE IF NOT EXISTS federationsender_queue_pdus (
+    -- The transaction ID that was generated before persisting the event.
+	transaction_id TEXT NOT NULL,
+    -- The domain part of the user ID the m.room.member event is for.
+	server_name TEXT NOT NULL,
+	-- The JSON NID from the federationsender_queue_pdus_json table.
+	json_nid BIGINT NOT NULL
+);
+
+CREATE UNIQUE INDEX IF NOT EXISTS federationsender_queue_pdus_pdus_json_nid_idx
+    ON federationsender_queue_pdus (json_nid, server_name);
+`
+
+const insertQueuePDUSQL = "" +
+	"INSERT INTO federationsender_queue_pdus (transaction_id, server_name, json_nid)" +
+	" VALUES ($1, $2, $3)"
+
+const deleteQueuePDUsSQL = "" +
+	"DELETE FROM federationsender_queue_pdus WHERE server_name = $1 AND json_nid IN ($2)"
+
+const selectQueueNextTransactionIDSQL = "" +
+	"SELECT transaction_id FROM federationsender_queue_pdus" +
+	" WHERE server_name = $1" +
+	" ORDER BY transaction_id ASC" +
+	" LIMIT 1"
+
+const selectQueuePDUsSQL = "" +
+	"SELECT json_nid FROM federationsender_queue_pdus" +
+	" WHERE server_name = $1" +
+	" LIMIT $2"
+
+const selectQueuePDUsReferenceJSONCountSQL = "" +
+	"SELECT COUNT(*) FROM federationsender_queue_pdus" +
+	" WHERE json_nid = $1"
+
+const selectQueuePDUsCountSQL = "" +
+	"SELECT COUNT(*) FROM federationsender_queue_pdus" +
+	" WHERE server_name = $1"
+
+const selectQueuePDUsServerNamesSQL = "" +
+	"SELECT DISTINCT server_name FROM federationsender_queue_pdus"
+
+type queuePDUsStatements struct {
+	db                                *sql.DB
+	insertQueuePDUStmt                *sql.Stmt
+	selectQueueNextTransactionIDStmt  *sql.Stmt
+	selectQueuePDUsStmt               *sql.Stmt
+	selectQueueReferenceJSONCountStmt *sql.Stmt
+	selectQueuePDUsCountStmt          *sql.Stmt
+	selectQueueServerNamesStmt        *sql.Stmt
+	// deleteQueuePDUsStmt *sql.Stmt - prepared at runtime due to variadic
+}
+
+func NewSQLiteQueuePDUsTable(db *sql.DB) (s *queuePDUsStatements, err error) {
+	s = &queuePDUsStatements{
+		db: db,
+	}
+	_, err = db.Exec(queuePDUsSchema)
+	if err != nil {
+		return
+	}
+	if s.insertQueuePDUStmt, err = db.Prepare(insertQueuePDUSQL); err != nil {
+		return
+	}
+	//if s.deleteQueuePDUsStmt, err = db.Prepare(deleteQueuePDUsSQL); err != nil {
+	//	return
+	//}
+	if s.selectQueueNextTransactionIDStmt, err = db.Prepare(selectQueueNextTransactionIDSQL); err != nil {
+		return
+	}
+	if s.selectQueuePDUsStmt, err = db.Prepare(selectQueuePDUsSQL); err != nil {
+		return
+	}
+	if s.selectQueueReferenceJSONCountStmt, err = db.Prepare(selectQueuePDUsReferenceJSONCountSQL); err != nil {
+		return
+	}
+	if s.selectQueuePDUsCountStmt, err = db.Prepare(selectQueuePDUsCountSQL); err != nil {
+		return
+	}
+	if s.selectQueueServerNamesStmt, err = db.Prepare(selectQueuePDUsServerNamesSQL); err != nil {
+		return
+	}
+	return
+}
+
+func (s *queuePDUsStatements) InsertQueuePDU(
+	ctx context.Context,
+	txn *sql.Tx,
+	transactionID gomatrixserverlib.TransactionID,
+	serverName gomatrixserverlib.ServerName,
+	nid int64,
+) error {
+	stmt := sqlutil.TxStmt(txn, s.insertQueuePDUStmt)
+	_, err := stmt.ExecContext(
+		ctx,
+		transactionID, // the transaction ID that we initially attempted
+		serverName,    // destination server name
+		nid,           // JSON blob NID
+	)
+	return err
+}
+
+func (s *queuePDUsStatements) DeleteQueuePDUs(
+	ctx context.Context, txn *sql.Tx,
+	serverName gomatrixserverlib.ServerName,
+	jsonNIDs []int64,
+) error {
+	deleteSQL := strings.Replace(deleteQueuePDUsSQL, "($2)", sqlutil.QueryVariadicOffset(len(jsonNIDs), 1), 1)
+	deleteStmt, err := txn.Prepare(deleteSQL)
+	if err != nil {
+		return fmt.Errorf("s.deleteQueueJSON s.db.Prepare: %w", err)
+	}
+
+	params := make([]interface{}, len(jsonNIDs)+1)
+	params[0] = serverName
+	for k, v := range jsonNIDs {
+		params[k+1] = v
+	}
+
+	stmt := sqlutil.TxStmt(txn, deleteStmt)
+	_, err = stmt.ExecContext(ctx, params...)
+	return err
+}
+
+func (s *queuePDUsStatements) SelectQueuePDUNextTransactionID(
+	ctx context.Context, txn *sql.Tx, serverName gomatrixserverlib.ServerName,
+) (gomatrixserverlib.TransactionID, error) {
+	var transactionID gomatrixserverlib.TransactionID
+	stmt := sqlutil.TxStmt(txn, s.selectQueueNextTransactionIDStmt)
+	err := stmt.QueryRowContext(ctx, serverName).Scan(&transactionID)
+	if err == sql.ErrNoRows {
+		return "", nil
+	}
+	return transactionID, err
+}
+
+func (s *queuePDUsStatements) SelectQueuePDUReferenceJSONCount(
+	ctx context.Context, txn *sql.Tx, jsonNID int64,
+) (int64, error) {
+	var count int64
+	stmt := sqlutil.TxStmt(txn, s.selectQueueReferenceJSONCountStmt)
+	err := stmt.QueryRowContext(ctx, jsonNID).Scan(&count)
+	if err == sql.ErrNoRows {
+		return -1, nil
+	}
+	return count, err
+}
+
+func (s *queuePDUsStatements) SelectQueuePDUCount(
+	ctx context.Context, txn *sql.Tx, serverName gomatrixserverlib.ServerName,
+) (int64, error) {
+	var count int64
+	stmt := sqlutil.TxStmt(txn, s.selectQueuePDUsCountStmt)
+	err := stmt.QueryRowContext(ctx, serverName).Scan(&count)
+	if err == sql.ErrNoRows {
+		// It's acceptable for there to be no rows referencing a given
+		// JSON NID but it's not an error condition. Just return as if
+		// there's a zero count.
+		return 0, nil
+	}
+	return count, err
+}
+
+func (s *queuePDUsStatements) SelectQueuePDUs(
+	ctx context.Context, txn *sql.Tx,
+	serverName gomatrixserverlib.ServerName,
+	limit int,
+) ([]int64, error) {
+	stmt := sqlutil.TxStmt(txn, s.selectQueuePDUsStmt)
+	rows, err := stmt.QueryContext(ctx, serverName, limit)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "queueFromStmt: rows.close() failed")
+	var result []int64
+	for rows.Next() {
+		var nid int64
+		if err = rows.Scan(&nid); err != nil {
+			return nil, err
+		}
+		result = append(result, nid)
+	}
+
+	return result, rows.Err()
+}
+
+func (s *queuePDUsStatements) SelectQueuePDUServerNames(
+	ctx context.Context, txn *sql.Tx,
+) ([]gomatrixserverlib.ServerName, error) {
+	stmt := sqlutil.TxStmt(txn, s.selectQueueServerNamesStmt)
+	rows, err := stmt.QueryContext(ctx)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "queueFromStmt: rows.close() failed")
+	var result []gomatrixserverlib.ServerName
+	for rows.Next() {
+		var serverName gomatrixserverlib.ServerName
+		if err = rows.Scan(&serverName); err != nil {
+			return nil, err
+		}
+		result = append(result, serverName)
+	}
+
+	return result, rows.Err()
+}

federationsender/storage/cosmosdb/storage.go

@@ -0,0 +1,95 @@
+// Copyright 2017-2018 New Vector Ltd
+// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"database/sql"
+
+	_ "github.com/mattn/go-sqlite3"
+
+	"github.com/matrix-org/dendrite/federationsender/storage/shared"
+	"github.com/matrix-org/dendrite/federationsender/storage/sqlite3/deltas"
+	"github.com/matrix-org/dendrite/internal/caching"
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/setup/config"
+)
+
+// Database stores information needed by the federation sender
+type Database struct {
+	shared.Database
+	sqlutil.PartitionOffsetStatements
+	db     *sql.DB
+	writer sqlutil.Writer
+}
+
+// NewDatabase opens a new database
+func NewDatabase(dbProperties *config.DatabaseOptions, cache caching.FederationSenderCache) (*Database, error) {
+	var d Database
+	var err error
+	if d.db, err = sqlutil.Open(dbProperties); err != nil {
+		return nil, err
+	}
+	d.writer = sqlutil.NewExclusiveWriter()
+	joinedHosts, err := NewSQLiteJoinedHostsTable(d.db)
+	if err != nil {
+		return nil, err
+	}
+	queuePDUs, err := NewSQLiteQueuePDUsTable(d.db)
+	if err != nil {
+		return nil, err
+	}
+	queueEDUs, err := NewSQLiteQueueEDUsTable(d.db)
+	if err != nil {
+		return nil, err
+	}
+	queueJSON, err := NewSQLiteQueueJSONTable(d.db)
+	if err != nil {
+		return nil, err
+	}
+	blacklist, err := NewSQLiteBlacklistTable(d.db)
+	if err != nil {
+		return nil, err
+	}
+	outboundPeeks, err := NewSQLiteOutboundPeeksTable(d.db)
+	if err != nil {
+		return nil, err
+	}
+	inboundPeeks, err := NewSQLiteInboundPeeksTable(d.db)
+	if err != nil {
+		return nil, err
+	}
+	m := sqlutil.NewMigrations()
+	deltas.LoadRemoveRoomsTable(m)
+	if err = m.RunDeltas(d.db, dbProperties); err != nil {
+		return nil, err
+	}
+	d.Database = shared.Database{
+		DB:                            d.db,
+		Cache:                         cache,
+		Writer:                        d.writer,
+		FederationSenderJoinedHosts:   joinedHosts,
+		FederationSenderQueuePDUs:     queuePDUs,
+		FederationSenderQueueEDUs:     queueEDUs,
+		FederationSenderQueueJSON:     queueJSON,
+		FederationSenderBlacklist:     blacklist,
+		FederationSenderOutboundPeeks: outboundPeeks,
+		FederationSenderInboundPeeks:  inboundPeeks,
+	}
+	if err = d.PartitionOffsetStatements.Prepare(d.db, d.writer, "federationsender"); err != nil {
+		return nil, err
+	}
+	return &d, nil
+}

federationsender/storage/storage.go

@@ -21,6 +21,7 @@ import (
 
 	"github.com/matrix-org/dendrite/federationsender/storage/postgres"
 	"github.com/matrix-org/dendrite/federationsender/storage/sqlite3"
+	"github.com/matrix-org/dendrite/federationsender/storage/cosmosdb"
 	"github.com/matrix-org/dendrite/internal/caching"
 	"github.com/matrix-org/dendrite/setup/config"
 )
@@ -28,6 +29,8 @@ import (
 // NewDatabase opens a new database
 func NewDatabase(dbProperties *config.DatabaseOptions, cache caching.FederationSenderCache) (Database, error) {
 	switch {
+	case dbProperties.ConnectionString.IsCosmosDB():
+		return cosmosdb.NewDatabase(dbProperties, cache)
 	case dbProperties.ConnectionString.IsSQLite():
 		return sqlite3.NewDatabase(dbProperties, cache)
 	case dbProperties.ConnectionString.IsPostgres():

federationsender/storage/storage_wasm.go

@@ -25,6 +25,8 @@ import (
 // NewDatabase opens a new database
 func NewDatabase(dbProperties *config.DatabaseOptions, cache caching.FederationSenderCache) (Database, error) {
 	switch {
+	case dbProperties.ConnectionString.IsCosmosDB():
+		return nil, fmt.Errorf("can't use CosmosDB implementation")
 	case dbProperties.ConnectionString.IsSQLite():
 		return sqlite3.NewDatabase(dbProperties, cache)
 	case dbProperties.ConnectionString.IsPostgres():

internal/cosmosdbutil/connection.go

@@ -0,0 +1,12 @@
+package cosmosdbutil
+
+import (
+	"github.com/matrix-org/dendrite/setup/config"
+	"strings"
+)
+
+func GetConnectionString(d *config.DataSource) config.DataSource {
+	var connString string
+	connString = string(*d)
+	return config.DataSource(strings.Replace(connString, "cosmosdb:", "file:", 1))
+}

internal/sqlutil/migrate.go

@@ -48,10 +48,15 @@ func (m *Migrations) RunDeltas(db *sql.DB, props *config.DatabaseOptions) error
 	if err != nil {
 		return fmt.Errorf("RunDeltas: Failed to collect migrations: %w", err)
 	}
-	if props.ConnectionString.IsPostgres() {
+	if props.ConnectionString.IsCosmosDB() {
 		if err = goose.SetDialect("postgres"); err != nil {
 			return err
 		}
+	} else if props.ConnectionString.IsPostgres() {
+		//HACK: Not supported
+		if err = goose.SetDialect("cosmosdb"); err != nil {
+			return err
+		}
 	} else if props.ConnectionString.IsSQLite() {
 		if err = goose.SetDialect("sqlite3"); err != nil {
 			return err

internal/sqlutil/trace.go

@@ -103,6 +103,11 @@ func Open(dbProperties *config.DatabaseOptions) (*sql.DB, error) {
 	var err error
 	var driverName, dsn string
 	switch {
+	case dbProperties.ConnectionString.IsCosmosDB():
+		//HACK: Not supported
+		driverName = "cosmosdb"
+		dsn = string(dbProperties.ConnectionString)
+		return nil, fmt.Errorf("CosmosDB %q", dbProperties.ConnectionString)
 	case dbProperties.ConnectionString.IsSQLite():
 		driverName = SQLiteDriverName()
 		dsn, err = ParseFileURI(dbProperties.ConnectionString)

keyserver/storage/cosmosdb/device_keys_table.go

@@ -0,0 +1,199 @@
+// Copyright 2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+	"strings"
+	"time"
+
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/keyserver/api"
+	"github.com/matrix-org/dendrite/keyserver/storage/tables"
+)
+
+var deviceKeysSchema = `
+-- Stores device keys for users
+CREATE TABLE IF NOT EXISTS keyserver_device_keys (
+    user_id TEXT NOT NULL,
+	device_id TEXT NOT NULL,
+	ts_added_secs BIGINT NOT NULL,
+	key_json TEXT NOT NULL,
+	stream_id BIGINT NOT NULL,
+	display_name TEXT,
+	-- Clobber based on tuple of user/device.
+    UNIQUE (user_id, device_id)
+);
+`
+
+const upsertDeviceKeysSQL = "" +
+	"INSERT INTO keyserver_device_keys (user_id, device_id, ts_added_secs, key_json, stream_id, display_name)" +
+	" VALUES ($1, $2, $3, $4, $5, $6)" +
+	" ON CONFLICT (user_id, device_id)" +
+	" DO UPDATE SET key_json = $4, stream_id = $5, display_name = $6"
+
+const selectDeviceKeysSQL = "" +
+	"SELECT key_json, stream_id, display_name FROM keyserver_device_keys WHERE user_id=$1 AND device_id=$2"
+
+const selectBatchDeviceKeysSQL = "" +
+	"SELECT device_id, key_json, stream_id, display_name FROM keyserver_device_keys WHERE user_id=$1 AND key_json <> ''"
+
+const selectMaxStreamForUserSQL = "" +
+	"SELECT MAX(stream_id) FROM keyserver_device_keys WHERE user_id=$1"
+
+const countStreamIDsForUserSQL = "" +
+	"SELECT COUNT(*) FROM keyserver_device_keys WHERE user_id=$1 AND stream_id IN ($2)"
+
+const deleteAllDeviceKeysSQL = "" +
+	"DELETE FROM keyserver_device_keys WHERE user_id=$1"
+
+type deviceKeysStatements struct {
+	db                         *sql.DB
+	upsertDeviceKeysStmt       *sql.Stmt
+	selectDeviceKeysStmt       *sql.Stmt
+	selectBatchDeviceKeysStmt  *sql.Stmt
+	selectMaxStreamForUserStmt *sql.Stmt
+	deleteAllDeviceKeysStmt    *sql.Stmt
+}
+
+func NewSqliteDeviceKeysTable(db *sql.DB) (tables.DeviceKeys, error) {
+	s := &deviceKeysStatements{
+		db: db,
+	}
+	_, err := db.Exec(deviceKeysSchema)
+	if err != nil {
+		return nil, err
+	}
+	if s.upsertDeviceKeysStmt, err = db.Prepare(upsertDeviceKeysSQL); err != nil {
+		return nil, err
+	}
+	if s.selectDeviceKeysStmt, err = db.Prepare(selectDeviceKeysSQL); err != nil {
+		return nil, err
+	}
+	if s.selectBatchDeviceKeysStmt, err = db.Prepare(selectBatchDeviceKeysSQL); err != nil {
+		return nil, err
+	}
+	if s.selectMaxStreamForUserStmt, err = db.Prepare(selectMaxStreamForUserSQL); err != nil {
+		return nil, err
+	}
+	if s.deleteAllDeviceKeysStmt, err = db.Prepare(deleteAllDeviceKeysSQL); err != nil {
+		return nil, err
+	}
+	return s, nil
+}
+
+func (s *deviceKeysStatements) DeleteAllDeviceKeys(ctx context.Context, txn *sql.Tx, userID string) error {
+	_, err := sqlutil.TxStmt(txn, s.deleteAllDeviceKeysStmt).ExecContext(ctx, userID)
+	return err
+}
+
+func (s *deviceKeysStatements) SelectBatchDeviceKeys(ctx context.Context, userID string, deviceIDs []string) ([]api.DeviceMessage, error) {
+	deviceIDMap := make(map[string]bool)
+	for _, d := range deviceIDs {
+		deviceIDMap[d] = true
+	}
+	rows, err := s.selectBatchDeviceKeysStmt.QueryContext(ctx, userID)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "selectBatchDeviceKeysStmt: rows.close() failed")
+	var result []api.DeviceMessage
+	for rows.Next() {
+		var dk api.DeviceMessage
+		dk.UserID = userID
+		var keyJSON string
+		var streamID int
+		var displayName sql.NullString
+		if err := rows.Scan(&dk.DeviceID, &keyJSON, &streamID, &displayName); err != nil {
+			return nil, err
+		}
+		dk.KeyJSON = []byte(keyJSON)
+		dk.StreamID = streamID
+		if displayName.Valid {
+			dk.DisplayName = displayName.String
+		}
+		// include the key if we want all keys (no device) or it was asked
+		if deviceIDMap[dk.DeviceID] || len(deviceIDs) == 0 {
+			result = append(result, dk)
+		}
+	}
+	return result, rows.Err()
+}
+
+func (s *deviceKeysStatements) SelectDeviceKeysJSON(ctx context.Context, keys []api.DeviceMessage) error {
+	for i, key := range keys {
+		var keyJSONStr string
+		var streamID int
+		var displayName sql.NullString
+		err := s.selectDeviceKeysStmt.QueryRowContext(ctx, key.UserID, key.DeviceID).Scan(&keyJSONStr, &streamID, &displayName)
+		if err != nil && err != sql.ErrNoRows {
+			return err
+		}
+		// this will be '' when there is no device
+		keys[i].KeyJSON = []byte(keyJSONStr)
+		keys[i].StreamID = streamID
+		if displayName.Valid {
+			keys[i].DisplayName = displayName.String
+		}
+	}
+	return nil
+}
+
+func (s *deviceKeysStatements) SelectMaxStreamIDForUser(ctx context.Context, txn *sql.Tx, userID string) (streamID int32, err error) {
+	// nullable if there are no results
+	var nullStream sql.NullInt32
+	err = sqlutil.TxStmt(txn, s.selectMaxStreamForUserStmt).QueryRowContext(ctx, userID).Scan(&nullStream)
+	if err == sql.ErrNoRows {
+		err = nil
+	}
+	if nullStream.Valid {
+		streamID = nullStream.Int32
+	}
+	return
+}
+
+func (s *deviceKeysStatements) CountStreamIDsForUser(ctx context.Context, userID string, streamIDs []int64) (int, error) {
+	iStreamIDs := make([]interface{}, len(streamIDs)+1)
+	iStreamIDs[0] = userID
+	for i := range streamIDs {
+		iStreamIDs[i+1] = streamIDs[i]
+	}
+	query := strings.Replace(countStreamIDsForUserSQL, "($2)", sqlutil.QueryVariadicOffset(len(streamIDs), 1), 1)
+	// nullable if there are no results
+	var count sql.NullInt32
+	err := s.db.QueryRowContext(ctx, query, iStreamIDs...).Scan(&count)
+	if err != nil {
+		return 0, err
+	}
+	if count.Valid {
+		return int(count.Int32), nil
+	}
+	return 0, nil
+}
+
+func (s *deviceKeysStatements) InsertDeviceKeys(ctx context.Context, txn *sql.Tx, keys []api.DeviceMessage) error {
+	for _, key := range keys {
+		now := time.Now().Unix()
+		_, err := sqlutil.TxStmt(txn, s.upsertDeviceKeysStmt).ExecContext(
+			ctx, key.UserID, key.DeviceID, now, string(key.KeyJSON), key.StreamID, key.DisplayName,
+		)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}

keyserver/storage/cosmosdb/key_changes_table.go

@@ -0,0 +1,104 @@
+// Copyright 2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+	"math"
+
+	"github.com/Shopify/sarama"
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/keyserver/storage/tables"
+)
+
+var keyChangesSchema = `
+-- Stores key change information about users. Used to determine when to send updated device lists to clients.
+CREATE TABLE IF NOT EXISTS keyserver_key_changes (
+	partition BIGINT NOT NULL,
+	offset BIGINT NOT NULL,
+	-- The key owner
+	user_id TEXT NOT NULL,
+	UNIQUE (partition, offset)
+);
+`
+
+// Replace based on partition|offset - we should never insert duplicates unless the kafka logs are wiped.
+// Rather than falling over, just overwrite (though this will mean clients with an existing sync token will
+// miss out on updates). TODO: Ideally we would detect when kafka logs are purged then purge this table too.
+const upsertKeyChangeSQL = "" +
+	"INSERT INTO keyserver_key_changes (partition, offset, user_id)" +
+	" VALUES ($1, $2, $3)" +
+	" ON CONFLICT (partition, offset)" +
+	" DO UPDATE SET user_id = $3"
+
+// select the highest offset for each user in the range. The grouping by user gives distinct entries and then we just
+// take the max offset value as the latest offset.
+const selectKeyChangesSQL = "" +
+	"SELECT user_id, MAX(offset) FROM keyserver_key_changes WHERE partition = $1 AND offset > $2 AND offset <= $3 GROUP BY user_id"
+
+type keyChangesStatements struct {
+	db                   *sql.DB
+	upsertKeyChangeStmt  *sql.Stmt
+	selectKeyChangesStmt *sql.Stmt
+}
+
+func NewSqliteKeyChangesTable(db *sql.DB) (tables.KeyChanges, error) {
+	s := &keyChangesStatements{
+		db: db,
+	}
+	_, err := db.Exec(keyChangesSchema)
+	if err != nil {
+		return nil, err
+	}
+	if s.upsertKeyChangeStmt, err = db.Prepare(upsertKeyChangeSQL); err != nil {
+		return nil, err
+	}
+	if s.selectKeyChangesStmt, err = db.Prepare(selectKeyChangesSQL); err != nil {
+		return nil, err
+	}
+	return s, nil
+}
+
+func (s *keyChangesStatements) InsertKeyChange(ctx context.Context, partition int32, offset int64, userID string) error {
+	_, err := s.upsertKeyChangeStmt.ExecContext(ctx, partition, offset, userID)
+	return err
+}
+
+func (s *keyChangesStatements) SelectKeyChanges(
+	ctx context.Context, partition int32, fromOffset, toOffset int64,
+) (userIDs []string, latestOffset int64, err error) {
+	if toOffset == sarama.OffsetNewest {
+		toOffset = math.MaxInt64
+	}
+	latestOffset = fromOffset
+	rows, err := s.selectKeyChangesStmt.QueryContext(ctx, partition, fromOffset, toOffset)
+	if err != nil {
+		return nil, 0, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "selectKeyChangesStmt: rows.close() failed")
+	for rows.Next() {
+		var userID string
+		var offset int64
+		if err := rows.Scan(&userID, &offset); err != nil {
+			return nil, 0, err
+		}
+		if offset > latestOffset {
+			latestOffset = offset
+		}
+		userIDs = append(userIDs, userID)
+	}
+	return
+}

keyserver/storage/cosmosdb/one_time_keys_table.go

@@ -0,0 +1,203 @@
+// Copyright 2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+	"encoding/json"
+	"time"
+
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/keyserver/api"
+	"github.com/matrix-org/dendrite/keyserver/storage/tables"
+)
+
+var oneTimeKeysSchema = `
+-- Stores one-time public keys for users
+CREATE TABLE IF NOT EXISTS keyserver_one_time_keys (
+    user_id TEXT NOT NULL,
+	device_id TEXT NOT NULL,
+	key_id TEXT NOT NULL,
+	algorithm TEXT NOT NULL,
+	ts_added_secs BIGINT NOT NULL,
+	key_json TEXT NOT NULL,
+	-- Clobber based on 4-uple of user/device/key/algorithm.
+    UNIQUE (user_id, device_id, key_id, algorithm)
+);
+`
+
+const upsertKeysSQL = "" +
+	"INSERT INTO keyserver_one_time_keys (user_id, device_id, key_id, algorithm, ts_added_secs, key_json)" +
+	" VALUES ($1, $2, $3, $4, $5, $6)" +
+	" ON CONFLICT (user_id, device_id, key_id, algorithm)" +
+	" DO UPDATE SET key_json = $6"
+
+const selectKeysSQL = "" +
+	"SELECT key_id, algorithm, key_json FROM keyserver_one_time_keys WHERE user_id=$1 AND device_id=$2"
+
+const selectKeysCountSQL = "" +
+	"SELECT algorithm, COUNT(key_id) FROM keyserver_one_time_keys WHERE user_id=$1 AND device_id=$2 GROUP BY algorithm"
+
+const deleteOneTimeKeySQL = "" +
+	"DELETE FROM keyserver_one_time_keys WHERE user_id = $1 AND device_id = $2 AND algorithm = $3 AND key_id = $4"
+
+const selectKeyByAlgorithmSQL = "" +
+	"SELECT key_id, key_json FROM keyserver_one_time_keys WHERE user_id = $1 AND device_id = $2 AND algorithm = $3 LIMIT 1"
+
+type oneTimeKeysStatements struct {
+	db                       *sql.DB
+	upsertKeysStmt           *sql.Stmt
+	selectKeysStmt           *sql.Stmt
+	selectKeysCountStmt      *sql.Stmt
+	selectKeyByAlgorithmStmt *sql.Stmt
+	deleteOneTimeKeyStmt     *sql.Stmt
+}
+
+func NewSqliteOneTimeKeysTable(db *sql.DB) (tables.OneTimeKeys, error) {
+	s := &oneTimeKeysStatements{
+		db: db,
+	}
+	_, err := db.Exec(oneTimeKeysSchema)
+	if err != nil {
+		return nil, err
+	}
+	if s.upsertKeysStmt, err = db.Prepare(upsertKeysSQL); err != nil {
+		return nil, err
+	}
+	if s.selectKeysStmt, err = db.Prepare(selectKeysSQL); err != nil {
+		return nil, err
+	}
+	if s.selectKeysCountStmt, err = db.Prepare(selectKeysCountSQL); err != nil {
+		return nil, err
+	}
+	if s.selectKeyByAlgorithmStmt, err = db.Prepare(selectKeyByAlgorithmSQL); err != nil {
+		return nil, err
+	}
+	if s.deleteOneTimeKeyStmt, err = db.Prepare(deleteOneTimeKeySQL); err != nil {
+		return nil, err
+	}
+	return s, nil
+}
+
+func (s *oneTimeKeysStatements) SelectOneTimeKeys(ctx context.Context, userID, deviceID string, keyIDsWithAlgorithms []string) (map[string]json.RawMessage, error) {
+	rows, err := s.selectKeysStmt.QueryContext(ctx, userID, deviceID)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "selectKeysStmt: rows.close() failed")
+
+	wantSet := make(map[string]bool, len(keyIDsWithAlgorithms))
+	for _, ka := range keyIDsWithAlgorithms {
+		wantSet[ka] = true
+	}
+
+	result := make(map[string]json.RawMessage)
+	for rows.Next() {
+		var keyID string
+		var algorithm string
+		var keyJSONStr string
+		if err := rows.Scan(&keyID, &algorithm, &keyJSONStr); err != nil {
+			return nil, err
+		}
+		keyIDWithAlgo := algorithm + ":" + keyID
+		if wantSet[keyIDWithAlgo] {
+			result[keyIDWithAlgo] = json.RawMessage(keyJSONStr)
+		}
+	}
+	return result, rows.Err()
+}
+
+func (s *oneTimeKeysStatements) CountOneTimeKeys(ctx context.Context, userID, deviceID string) (*api.OneTimeKeysCount, error) {
+	counts := &api.OneTimeKeysCount{
+		DeviceID: deviceID,
+		UserID:   userID,
+		KeyCount: make(map[string]int),
+	}
+	rows, err := s.selectKeysCountStmt.QueryContext(ctx, userID, deviceID)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "selectKeysCountStmt: rows.close() failed")
+	for rows.Next() {
+		var algorithm string
+		var count int
+		if err = rows.Scan(&algorithm, &count); err != nil {
+			return nil, err
+		}
+		counts.KeyCount[algorithm] = count
+	}
+	return counts, nil
+}
+
+func (s *oneTimeKeysStatements) InsertOneTimeKeys(
+	ctx context.Context, txn *sql.Tx, keys api.OneTimeKeys,
+) (*api.OneTimeKeysCount, error) {
+	now := time.Now().Unix()
+	counts := &api.OneTimeKeysCount{
+		DeviceID: keys.DeviceID,
+		UserID:   keys.UserID,
+		KeyCount: make(map[string]int),
+	}
+	for keyIDWithAlgo, keyJSON := range keys.KeyJSON {
+		algo, keyID := keys.Split(keyIDWithAlgo)
+		_, err := sqlutil.TxStmt(txn, s.upsertKeysStmt).ExecContext(
+			ctx, keys.UserID, keys.DeviceID, keyID, algo, now, string(keyJSON),
+		)
+		if err != nil {
+			return nil, err
+		}
+	}
+	rows, err := sqlutil.TxStmt(txn, s.selectKeysCountStmt).QueryContext(ctx, keys.UserID, keys.DeviceID)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "selectKeysCountStmt: rows.close() failed")
+	for rows.Next() {
+		var algorithm string
+		var count int
+		if err = rows.Scan(&algorithm, &count); err != nil {
+			return nil, err
+		}
+		counts.KeyCount[algorithm] = count
+	}
+
+	return counts, rows.Err()
+}
+
+func (s *oneTimeKeysStatements) SelectAndDeleteOneTimeKey(
+	ctx context.Context, txn *sql.Tx, userID, deviceID, algorithm string,
+) (map[string]json.RawMessage, error) {
+	var keyID string
+	var keyJSON string
+	err := sqlutil.TxStmtContext(ctx, txn, s.selectKeyByAlgorithmStmt).QueryRowContext(ctx, userID, deviceID, algorithm).Scan(&keyID, &keyJSON)
+	if err != nil {
+		if err == sql.ErrNoRows {
+			return nil, nil
+		}
+		return nil, err
+	}
+	_, err = sqlutil.TxStmtContext(ctx, txn, s.deleteOneTimeKeyStmt).ExecContext(ctx, userID, deviceID, algorithm, keyID)
+	if err != nil {
+		return nil, err
+	}
+	if keyJSON == "" {
+		return nil, nil
+	}
+	return map[string]json.RawMessage{
+		algorithm + ":" + keyID: json.RawMessage(keyJSON),
+	}, err
+}

keyserver/storage/cosmosdb/stale_device_lists.go

@@ -0,0 +1,121 @@
+// Copyright 2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+	"time"
+
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/keyserver/storage/tables"
+	"github.com/matrix-org/gomatrixserverlib"
+)
+
+var staleDeviceListsSchema = `
+-- Stores whether a user's device lists are stale or not.
+CREATE TABLE IF NOT EXISTS keyserver_stale_device_lists (
+    user_id TEXT PRIMARY KEY NOT NULL,
+	domain TEXT NOT NULL,
+	is_stale BOOLEAN NOT NULL,
+	ts_added_secs BIGINT NOT NULL
+);
+
+CREATE INDEX IF NOT EXISTS keyserver_stale_device_lists_idx ON keyserver_stale_device_lists (domain, is_stale);
+`
+
+const upsertStaleDeviceListSQL = "" +
+	"INSERT INTO keyserver_stale_device_lists (user_id, domain, is_stale, ts_added_secs)" +
+	" VALUES ($1, $2, $3, $4)" +
+	" ON CONFLICT (user_id)" +
+	" DO UPDATE SET is_stale = $3, ts_added_secs = $4"
+
+const selectStaleDeviceListsWithDomainsSQL = "" +
+	"SELECT user_id FROM keyserver_stale_device_lists WHERE is_stale = $1 AND domain = $2"
+
+const selectStaleDeviceListsSQL = "" +
+	"SELECT user_id FROM keyserver_stale_device_lists WHERE is_stale = $1"
+
+type staleDeviceListsStatements struct {
+	db                                    *sql.DB
+	upsertStaleDeviceListStmt             *sql.Stmt
+	selectStaleDeviceListsWithDomainsStmt *sql.Stmt
+	selectStaleDeviceListsStmt            *sql.Stmt
+}
+
+func NewSqliteStaleDeviceListsTable(db *sql.DB) (tables.StaleDeviceLists, error) {
+	s := &staleDeviceListsStatements{
+		db: db,
+	}
+	_, err := db.Exec(staleDeviceListsSchema)
+	if err != nil {
+		return nil, err
+	}
+	if s.upsertStaleDeviceListStmt, err = db.Prepare(upsertStaleDeviceListSQL); err != nil {
+		return nil, err
+	}
+	if s.selectStaleDeviceListsStmt, err = db.Prepare(selectStaleDeviceListsSQL); err != nil {
+		return nil, err
+	}
+	if s.selectStaleDeviceListsWithDomainsStmt, err = db.Prepare(selectStaleDeviceListsWithDomainsSQL); err != nil {
+		return nil, err
+	}
+	return s, nil
+}
+
+func (s *staleDeviceListsStatements) InsertStaleDeviceList(ctx context.Context, userID string, isStale bool) error {
+	_, domain, err := gomatrixserverlib.SplitID('@', userID)
+	if err != nil {
+		return err
+	}
+	_, err = s.upsertStaleDeviceListStmt.ExecContext(ctx, userID, string(domain), isStale, time.Now().Unix())
+	return err
+}
+
+func (s *staleDeviceListsStatements) SelectUserIDsWithStaleDeviceLists(ctx context.Context, domains []gomatrixserverlib.ServerName) ([]string, error) {
+	// we only query for 1 domain or all domains so optimise for those use cases
+	if len(domains) == 0 {
+		rows, err := s.selectStaleDeviceListsStmt.QueryContext(ctx, true)
+		if err != nil {
+			return nil, err
+		}
+		return rowsToUserIDs(ctx, rows)
+	}
+	var result []string
+	for _, domain := range domains {
+		rows, err := s.selectStaleDeviceListsWithDomainsStmt.QueryContext(ctx, true, string(domain))
+		if err != nil {
+			return nil, err
+		}
+		userIDs, err := rowsToUserIDs(ctx, rows)
+		if err != nil {
+			return nil, err
+		}
+		result = append(result, userIDs...)
+	}
+	return result, nil
+}
+
+func rowsToUserIDs(ctx context.Context, rows *sql.Rows) (result []string, err error) {
+	defer internal.CloseAndLogIfError(ctx, rows, "closing rowsToUserIDs failed")
+	for rows.Next() {
+		var userID string
+		if err := rows.Scan(&userID); err != nil {
+			return nil, err
+		}
+		result = append(result, userID)
+	}
+	return result, rows.Err()
+}

keyserver/storage/cosmosdb/storage.go

@@ -0,0 +1,52 @@
+// Copyright 2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/keyserver/storage/shared"
+	"github.com/matrix-org/dendrite/setup/config"
+)
+
+func NewDatabase(dbProperties *config.DatabaseOptions) (*shared.Database, error) {
+	db, err := sqlutil.Open(dbProperties)
+	if err != nil {
+		return nil, err
+	}
+	otk, err := NewSqliteOneTimeKeysTable(db)
+	if err != nil {
+		return nil, err
+	}
+	dk, err := NewSqliteDeviceKeysTable(db)
+	if err != nil {
+		return nil, err
+	}
+	kc, err := NewSqliteKeyChangesTable(db)
+	if err != nil {
+		return nil, err
+	}
+	sdl, err := NewSqliteStaleDeviceListsTable(db)
+	if err != nil {
+		return nil, err
+	}
+	return &shared.Database{
+		DB:                    db,
+		Writer:                sqlutil.NewExclusiveWriter(),
+		OneTimeKeysTable:      otk,
+		DeviceKeysTable:       dk,
+		KeyChangesTable:       kc,
+		StaleDeviceListsTable: sdl,
+	}, nil
+}

keyserver/storage/storage.go

@@ -19,6 +19,7 @@ package storage
 import (
 	"fmt"
 
+	"github.com/matrix-org/dendrite/keyserver/storage/cosmosdb"
 	"github.com/matrix-org/dendrite/keyserver/storage/postgres"
 	"github.com/matrix-org/dendrite/keyserver/storage/sqlite3"
 	"github.com/matrix-org/dendrite/setup/config"
@@ -28,6 +29,8 @@ import (
 // and sets postgres connection parameters
 func NewDatabase(dbProperties *config.DatabaseOptions) (Database, error) {
 	switch {
+	case dbProperties.ConnectionString.IsCosmosDB():
+		return cosmosdb.NewDatabase(dbProperties)
 	case dbProperties.ConnectionString.IsSQLite():
 		return sqlite3.NewDatabase(dbProperties)
 	case dbProperties.ConnectionString.IsPostgres():

keyserver/storage/storage_wasm.go

@@ -23,6 +23,8 @@ import (
 
 func NewDatabase(dbProperties *config.DatabaseOptions) (Database, error) {
 	switch {
+	case dbProperties.ConnectionString.IsCosmosDB():
+		return nil, fmt.Errorf("can't use CosmosDB implementation")
 	case dbProperties.ConnectionString.IsSQLite():
 		return sqlite3.NewDatabase(dbProperties)
 	case dbProperties.ConnectionString.IsPostgres():

mediaapi/storage/cosmosdb/media_repository_table.go

@@ -0,0 +1,150 @@
+// Copyright 2017-2018 New Vector Ltd
+// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+	"time"
+
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/mediaapi/types"
+	"github.com/matrix-org/gomatrixserverlib"
+)
+
+const mediaSchema = `
+-- The media_repository table holds metadata for each media file stored and accessible to the local server,
+-- the actual file is stored separately.
+CREATE TABLE IF NOT EXISTS mediaapi_media_repository (
+    -- The id used to refer to the media.
+    -- For uploads to this server this is a base64-encoded sha256 hash of the file data
+    -- For media from remote servers, this can be any unique identifier string
+    media_id TEXT NOT NULL,
+    -- The origin of the media as requested by the client. Should be a homeserver domain.
+    media_origin TEXT NOT NULL,
+    -- The MIME-type of the media file as specified when uploading.
+    content_type TEXT NOT NULL,
+    -- Size of the media file in bytes.
+    file_size_bytes INTEGER NOT NULL,
+    -- When the content was uploaded in UNIX epoch ms.
+    creation_ts INTEGER NOT NULL,
+    -- The file name with which the media was uploaded.
+    upload_name TEXT NOT NULL,
+    -- Alternate RFC 4648 unpadded base64 encoding string representation of a SHA-256 hash sum of the file data.
+    base64hash TEXT NOT NULL,
+    -- The user who uploaded the file. Should be a Matrix user ID.
+    user_id TEXT NOT NULL
+);
+CREATE UNIQUE INDEX IF NOT EXISTS mediaapi_media_repository_index ON mediaapi_media_repository (media_id, media_origin);
+`
+
+const insertMediaSQL = `
+INSERT INTO mediaapi_media_repository (media_id, media_origin, content_type, file_size_bytes, creation_ts, upload_name, base64hash, user_id)
+    VALUES ($1, $2, $3, $4, $5, $6, $7, $8)
+`
+
+const selectMediaSQL = `
+SELECT content_type, file_size_bytes, creation_ts, upload_name, base64hash, user_id FROM mediaapi_media_repository WHERE media_id = $1 AND media_origin = $2
+`
+
+const selectMediaByHashSQL = `
+SELECT content_type, file_size_bytes, creation_ts, upload_name, media_id, user_id FROM mediaapi_media_repository WHERE base64hash = $1 AND media_origin = $2
+`
+
+type mediaStatements struct {
+	db                    *sql.DB
+	writer                sqlutil.Writer
+	insertMediaStmt       *sql.Stmt
+	selectMediaStmt       *sql.Stmt
+	selectMediaByHashStmt *sql.Stmt
+}
+
+func (s *mediaStatements) prepare(db *sql.DB, writer sqlutil.Writer) (err error) {
+	s.db = db
+	s.writer = writer
+
+	_, err = db.Exec(mediaSchema)
+	if err != nil {
+		return
+	}
+
+	return statementList{
+		{&s.insertMediaStmt, insertMediaSQL},
+		{&s.selectMediaStmt, selectMediaSQL},
+		{&s.selectMediaByHashStmt, selectMediaByHashSQL},
+	}.prepare(db)
+}
+
+func (s *mediaStatements) insertMedia(
+	ctx context.Context, mediaMetadata *types.MediaMetadata,
+) error {
+	mediaMetadata.CreationTimestamp = types.UnixMs(time.Now().UnixNano() / 1000000)
+	return s.writer.Do(s.db, nil, func(txn *sql.Tx) error {
+		stmt := sqlutil.TxStmt(txn, s.insertMediaStmt)
+		_, err := stmt.ExecContext(
+			ctx,
+			mediaMetadata.MediaID,
+			mediaMetadata.Origin,
+			mediaMetadata.ContentType,
+			mediaMetadata.FileSizeBytes,
+			mediaMetadata.CreationTimestamp,
+			mediaMetadata.UploadName,
+			mediaMetadata.Base64Hash,
+			mediaMetadata.UserID,
+		)
+		return err
+	})
+}
+
+func (s *mediaStatements) selectMedia(
+	ctx context.Context, mediaID types.MediaID, mediaOrigin gomatrixserverlib.ServerName,
+) (*types.MediaMetadata, error) {
+	mediaMetadata := types.MediaMetadata{
+		MediaID: mediaID,
+		Origin:  mediaOrigin,
+	}
+	err := s.selectMediaStmt.QueryRowContext(
+		ctx, mediaMetadata.MediaID, mediaMetadata.Origin,
+	).Scan(
+		&mediaMetadata.ContentType,
+		&mediaMetadata.FileSizeBytes,
+		&mediaMetadata.CreationTimestamp,
+		&mediaMetadata.UploadName,
+		&mediaMetadata.Base64Hash,
+		&mediaMetadata.UserID,
+	)
+	return &mediaMetadata, err
+}
+
+func (s *mediaStatements) selectMediaByHash(
+	ctx context.Context, mediaHash types.Base64Hash, mediaOrigin gomatrixserverlib.ServerName,
+) (*types.MediaMetadata, error) {
+	mediaMetadata := types.MediaMetadata{
+		Base64Hash: mediaHash,
+		Origin:     mediaOrigin,
+	}
+	err := s.selectMediaStmt.QueryRowContext(
+		ctx, mediaMetadata.Base64Hash, mediaMetadata.Origin,
+	).Scan(
+		&mediaMetadata.ContentType,
+		&mediaMetadata.FileSizeBytes,
+		&mediaMetadata.CreationTimestamp,
+		&mediaMetadata.UploadName,
+		&mediaMetadata.MediaID,
+		&mediaMetadata.UserID,
+	)
+	return &mediaMetadata, err
+}

mediaapi/storage/cosmosdb/prepare.go

@@ -0,0 +1,38 @@
+// Copyright 2017-2018 New Vector Ltd
+// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// FIXME: This should be made internal!
+
+package cosmosdb
+
+import (
+	"database/sql"
+)
+
+// a statementList is a list of SQL statements to prepare and a pointer to where to store the resulting prepared statement.
+type statementList []struct {
+	statement **sql.Stmt
+	sql       string
+}
+
+// prepare the SQL for each statement in the list and assign the result to the prepared statement.
+func (s statementList) prepare(db *sql.DB) (err error) {
+	for _, statement := range s {
+		if *statement.statement, err = db.Prepare(statement.sql); err != nil {
+			return
+		}
+	}
+	return
+}

mediaapi/storage/cosmosdb/sql.go

@@ -0,0 +1,38 @@
+// Copyright 2017-2018 New Vector Ltd
+// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"database/sql"
+
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+)
+
+type statements struct {
+	media     mediaStatements
+	thumbnail thumbnailStatements
+}
+
+func (s *statements) prepare(db *sql.DB, writer sqlutil.Writer) (err error) {
+	if err = s.media.prepare(db, writer); err != nil {
+		return
+	}
+	if err = s.thumbnail.prepare(db, writer); err != nil {
+		return
+	}
+
+	return
+}

mediaapi/storage/cosmosdb/storage.go

@@ -0,0 +1,124 @@
+// Copyright 2017-2018 New Vector Ltd
+// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+
+	// Import the postgres database driver.
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/mediaapi/types"
+	"github.com/matrix-org/dendrite/setup/config"
+	"github.com/matrix-org/gomatrixserverlib"
+	_ "github.com/mattn/go-sqlite3"
+)
+
+// Database is used to store metadata about a repository of media files.
+type Database struct {
+	statements statements
+	db         *sql.DB
+	writer     sqlutil.Writer
+}
+
+// Open opens a postgres database.
+func Open(dbProperties *config.DatabaseOptions) (*Database, error) {
+	d := Database{
+		writer: sqlutil.NewExclusiveWriter(),
+	}
+	var err error
+	if d.db, err = sqlutil.Open(dbProperties); err != nil {
+		return nil, err
+	}
+	if err = d.statements.prepare(d.db, d.writer); err != nil {
+		return nil, err
+	}
+	return &d, nil
+}
+
+// StoreMediaMetadata inserts the metadata about the uploaded media into the database.
+// Returns an error if the combination of MediaID and Origin are not unique in the table.
+func (d *Database) StoreMediaMetadata(
+	ctx context.Context, mediaMetadata *types.MediaMetadata,
+) error {
+	return d.statements.media.insertMedia(ctx, mediaMetadata)
+}
+
+// GetMediaMetadata returns metadata about media stored on this server.
+// The media could have been uploaded to this server or fetched from another server and cached here.
+// Returns nil metadata if there is no metadata associated with this media.
+func (d *Database) GetMediaMetadata(
+	ctx context.Context, mediaID types.MediaID, mediaOrigin gomatrixserverlib.ServerName,
+) (*types.MediaMetadata, error) {
+	mediaMetadata, err := d.statements.media.selectMedia(ctx, mediaID, mediaOrigin)
+	if err != nil && err == sql.ErrNoRows {
+		return nil, nil
+	}
+	return mediaMetadata, err
+}
+
+// GetMediaMetadataByHash returns metadata about media stored on this server.
+// The media could have been uploaded to this server or fetched from another server and cached here.
+// Returns nil metadata if there is no metadata associated with this media.
+func (d *Database) GetMediaMetadataByHash(
+	ctx context.Context, mediaHash types.Base64Hash, mediaOrigin gomatrixserverlib.ServerName,
+) (*types.MediaMetadata, error) {
+	mediaMetadata, err := d.statements.media.selectMediaByHash(ctx, mediaHash, mediaOrigin)
+	if err != nil && err == sql.ErrNoRows {
+		return nil, nil
+	}
+	return mediaMetadata, err
+}
+
+// StoreThumbnail inserts the metadata about the thumbnail into the database.
+// Returns an error if the combination of MediaID and Origin are not unique in the table.
+func (d *Database) StoreThumbnail(
+	ctx context.Context, thumbnailMetadata *types.ThumbnailMetadata,
+) error {
+	return d.statements.thumbnail.insertThumbnail(ctx, thumbnailMetadata)
+}
+
+// GetThumbnail returns metadata about a specific thumbnail.
+// The media could have been uploaded to this server or fetched from another server and cached here.
+// Returns nil metadata if there is no metadata associated with this thumbnail.
+func (d *Database) GetThumbnail(
+	ctx context.Context,
+	mediaID types.MediaID,
+	mediaOrigin gomatrixserverlib.ServerName,
+	width, height int,
+	resizeMethod string,
+) (*types.ThumbnailMetadata, error) {
+	thumbnailMetadata, err := d.statements.thumbnail.selectThumbnail(
+		ctx, mediaID, mediaOrigin, width, height, resizeMethod,
+	)
+	if err != nil && err == sql.ErrNoRows {
+		return nil, nil
+	}
+	return thumbnailMetadata, err
+}
+
+// GetThumbnails returns metadata about all thumbnails for a specific media stored on this server.
+// The media could have been uploaded to this server or fetched from another server and cached here.
+// Returns nil metadata if there are no thumbnails associated with this media.
+func (d *Database) GetThumbnails(
+	ctx context.Context, mediaID types.MediaID, mediaOrigin gomatrixserverlib.ServerName,
+) ([]*types.ThumbnailMetadata, error) {
+	thumbnails, err := d.statements.thumbnail.selectThumbnails(ctx, mediaID, mediaOrigin)
+	if err != nil && err == sql.ErrNoRows {
+		return nil, nil
+	}
+	return thumbnails, err
+}

mediaapi/storage/cosmosdb/thumbnail_table.go

@@ -0,0 +1,171 @@
+// Copyright 2017-2018 New Vector Ltd
+// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+	"time"
+
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/mediaapi/types"
+	"github.com/matrix-org/gomatrixserverlib"
+)
+
+const thumbnailSchema = `
+-- The mediaapi_thumbnail table holds metadata for each thumbnail file stored and accessible to the local server,
+-- the actual file is stored separately.
+CREATE TABLE IF NOT EXISTS mediaapi_thumbnail (
+    media_id TEXT NOT NULL,
+    media_origin TEXT NOT NULL,
+    content_type TEXT NOT NULL,
+    file_size_bytes INTEGER NOT NULL,
+    creation_ts INTEGER NOT NULL,
+    width INTEGER NOT NULL,
+    height INTEGER NOT NULL,
+    resize_method TEXT NOT NULL
+);
+CREATE UNIQUE INDEX IF NOT EXISTS mediaapi_thumbnail_index ON mediaapi_thumbnail (media_id, media_origin, width, height, resize_method);
+`
+
+const insertThumbnailSQL = `
+INSERT INTO mediaapi_thumbnail (media_id, media_origin, content_type, file_size_bytes, creation_ts, width, height, resize_method)
+    VALUES ($1, $2, $3, $4, $5, $6, $7, $8)
+`
+
+// Note: this selects one specific thumbnail
+const selectThumbnailSQL = `
+SELECT content_type, file_size_bytes, creation_ts FROM mediaapi_thumbnail WHERE media_id = $1 AND media_origin = $2 AND width = $3 AND height = $4 AND resize_method = $5
+`
+
+// Note: this selects all thumbnails for a media_origin and media_id
+const selectThumbnailsSQL = `
+SELECT content_type, file_size_bytes, creation_ts, width, height, resize_method FROM mediaapi_thumbnail WHERE media_id = $1 AND media_origin = $2
+`
+
+type thumbnailStatements struct {
+	db                   *sql.DB
+	writer               sqlutil.Writer
+	insertThumbnailStmt  *sql.Stmt
+	selectThumbnailStmt  *sql.Stmt
+	selectThumbnailsStmt *sql.Stmt
+}
+
+func (s *thumbnailStatements) prepare(db *sql.DB, writer sqlutil.Writer) (err error) {
+	_, err = db.Exec(thumbnailSchema)
+	if err != nil {
+		return
+	}
+	s.db = db
+	s.writer = writer
+
+	return statementList{
+		{&s.insertThumbnailStmt, insertThumbnailSQL},
+		{&s.selectThumbnailStmt, selectThumbnailSQL},
+		{&s.selectThumbnailsStmt, selectThumbnailsSQL},
+	}.prepare(db)
+}
+
+func (s *thumbnailStatements) insertThumbnail(
+	ctx context.Context, thumbnailMetadata *types.ThumbnailMetadata,
+) error {
+	thumbnailMetadata.MediaMetadata.CreationTimestamp = types.UnixMs(time.Now().UnixNano() / 1000000)
+	return s.writer.Do(s.db, nil, func(txn *sql.Tx) error {
+		stmt := sqlutil.TxStmt(txn, s.insertThumbnailStmt)
+		_, err := stmt.ExecContext(
+			ctx,
+			thumbnailMetadata.MediaMetadata.MediaID,
+			thumbnailMetadata.MediaMetadata.Origin,
+			thumbnailMetadata.MediaMetadata.ContentType,
+			thumbnailMetadata.MediaMetadata.FileSizeBytes,
+			thumbnailMetadata.MediaMetadata.CreationTimestamp,
+			thumbnailMetadata.ThumbnailSize.Width,
+			thumbnailMetadata.ThumbnailSize.Height,
+			thumbnailMetadata.ThumbnailSize.ResizeMethod,
+		)
+		return err
+	})
+}
+
+func (s *thumbnailStatements) selectThumbnail(
+	ctx context.Context,
+	mediaID types.MediaID,
+	mediaOrigin gomatrixserverlib.ServerName,
+	width, height int,
+	resizeMethod string,
+) (*types.ThumbnailMetadata, error) {
+	thumbnailMetadata := types.ThumbnailMetadata{
+		MediaMetadata: &types.MediaMetadata{
+			MediaID: mediaID,
+			Origin:  mediaOrigin,
+		},
+		ThumbnailSize: types.ThumbnailSize{
+			Width:        width,
+			Height:       height,
+			ResizeMethod: resizeMethod,
+		},
+	}
+	err := s.selectThumbnailStmt.QueryRowContext(
+		ctx,
+		thumbnailMetadata.MediaMetadata.MediaID,
+		thumbnailMetadata.MediaMetadata.Origin,
+		thumbnailMetadata.ThumbnailSize.Width,
+		thumbnailMetadata.ThumbnailSize.Height,
+		thumbnailMetadata.ThumbnailSize.ResizeMethod,
+	).Scan(
+		&thumbnailMetadata.MediaMetadata.ContentType,
+		&thumbnailMetadata.MediaMetadata.FileSizeBytes,
+		&thumbnailMetadata.MediaMetadata.CreationTimestamp,
+	)
+	return &thumbnailMetadata, err
+}
+
+func (s *thumbnailStatements) selectThumbnails(
+	ctx context.Context, mediaID types.MediaID, mediaOrigin gomatrixserverlib.ServerName,
+) ([]*types.ThumbnailMetadata, error) {
+	rows, err := s.selectThumbnailsStmt.QueryContext(
+		ctx, mediaID, mediaOrigin,
+	)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "selectThumbnails: rows.close() failed")
+
+	var thumbnails []*types.ThumbnailMetadata
+	for rows.Next() {
+		thumbnailMetadata := types.ThumbnailMetadata{
+			MediaMetadata: &types.MediaMetadata{
+				MediaID: mediaID,
+				Origin:  mediaOrigin,
+			},
+		}
+		err = rows.Scan(
+			&thumbnailMetadata.MediaMetadata.ContentType,
+			&thumbnailMetadata.MediaMetadata.FileSizeBytes,
+			&thumbnailMetadata.MediaMetadata.CreationTimestamp,
+			&thumbnailMetadata.ThumbnailSize.Width,
+			&thumbnailMetadata.ThumbnailSize.Height,
+			&thumbnailMetadata.ThumbnailSize.ResizeMethod,
+		)
+		if err != nil {
+			return nil, err
+		}
+		thumbnails = append(thumbnails, &thumbnailMetadata)
+	}
+
+	return thumbnails, rows.Err()
+}

mediaapi/storage/storage.go

@@ -19,6 +19,7 @@ package storage
 import (
 	"fmt"
 
+	"github.com/matrix-org/dendrite/mediaapi/storage/cosmosdb"
 	"github.com/matrix-org/dendrite/mediaapi/storage/postgres"
 	"github.com/matrix-org/dendrite/mediaapi/storage/sqlite3"
 	"github.com/matrix-org/dendrite/setup/config"
@@ -27,6 +28,8 @@ import (
 // Open opens a postgres database.
 func Open(dbProperties *config.DatabaseOptions) (Database, error) {
 	switch {
+	case dbProperties.ConnectionString.IsCosmosDB():
+		return cosmosdb.Open(dbProperties)
 	case dbProperties.ConnectionString.IsSQLite():
 		return sqlite3.Open(dbProperties)
 	case dbProperties.ConnectionString.IsPostgres():

mediaapi/storage/storage_wasm.go

@@ -24,6 +24,8 @@ import (
 // Open opens a postgres database.
 func Open(dbProperties *config.DatabaseOptions) (Database, error) {
 	switch {
+	case dbProperties.ConnectionString.IsCosmosDB():
+		return nil, fmt.Errorf("can't use CosmosDB implementation")
 	case dbProperties.ConnectionString.IsSQLite():
 		return sqlite3.Open(dbProperties)
 	case dbProperties.ConnectionString.IsPostgres():

roomserver/storage/cosmosdb/event_json_table.go

@@ -0,0 +1,107 @@
+// Copyright 2017-2018 New Vector Ltd
+// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+	"strings"
+
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/roomserver/storage/shared"
+	"github.com/matrix-org/dendrite/roomserver/storage/tables"
+	"github.com/matrix-org/dendrite/roomserver/types"
+)
+
+const eventJSONSchema = `
+  CREATE TABLE IF NOT EXISTS roomserver_event_json (
+    event_nid INTEGER NOT NULL PRIMARY KEY,
+    event_json TEXT NOT NULL
+  );
+`
+
+const insertEventJSONSQL = `
+	INSERT OR REPLACE INTO roomserver_event_json (event_nid, event_json) VALUES ($1, $2)
+`
+
+// Bulk event JSON lookup by numeric event ID.
+// Sort by the numeric event ID.
+// This means that we can use binary search to lookup by numeric event ID.
+const bulkSelectEventJSONSQL = `
+	SELECT event_nid, event_json FROM roomserver_event_json
+	  WHERE event_nid IN ($1)
+	  ORDER BY event_nid ASC
+`
+
+type eventJSONStatements struct {
+	db                      *sql.DB
+	insertEventJSONStmt     *sql.Stmt
+	bulkSelectEventJSONStmt *sql.Stmt
+}
+
+func NewSqliteEventJSONTable(db *sql.DB) (tables.EventJSON, error) {
+	s := &eventJSONStatements{
+		db: db,
+	}
+	_, err := db.Exec(eventJSONSchema)
+	if err != nil {
+		return nil, err
+	}
+	return s, shared.StatementList{
+		{&s.insertEventJSONStmt, insertEventJSONSQL},
+		{&s.bulkSelectEventJSONStmt, bulkSelectEventJSONSQL},
+	}.Prepare(db)
+}
+
+func (s *eventJSONStatements) InsertEventJSON(
+	ctx context.Context, txn *sql.Tx, eventNID types.EventNID, eventJSON []byte,
+) error {
+	_, err := sqlutil.TxStmt(txn, s.insertEventJSONStmt).ExecContext(ctx, int64(eventNID), eventJSON)
+	return err
+}
+
+func (s *eventJSONStatements) BulkSelectEventJSON(
+	ctx context.Context, eventNIDs []types.EventNID,
+) ([]tables.EventJSONPair, error) {
+	iEventNIDs := make([]interface{}, len(eventNIDs))
+	for k, v := range eventNIDs {
+		iEventNIDs[k] = v
+	}
+	selectOrig := strings.Replace(bulkSelectEventJSONSQL, "($1)", sqlutil.QueryVariadic(len(iEventNIDs)), 1)
+
+	rows, err := s.db.QueryContext(ctx, selectOrig, iEventNIDs...)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "bulkSelectEventJSON: rows.close() failed")
+
+	// We know that we will only get as many results as event NIDs
+	// because of the unique constraint on event NIDs.
+	// So we can allocate an array of the correct size now.
+	// We might get fewer results than NIDs so we adjust the length of the slice before returning it.
+	results := make([]tables.EventJSONPair, len(eventNIDs))
+	i := 0
+	for ; rows.Next(); i++ {
+		result := &results[i]
+		var eventNID int64
+		if err := rows.Scan(&eventNID, &result.EventJSON); err != nil {
+			return nil, err
+		}
+		result.EventNID = types.EventNID(eventNID)
+	}
+	return results[:i], nil
+}

roomserver/storage/cosmosdb/event_state_keys_table.go

@@ -0,0 +1,163 @@
+// Copyright 2017-2018 New Vector Ltd
+// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+	"strings"
+
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/roomserver/storage/shared"
+	"github.com/matrix-org/dendrite/roomserver/storage/tables"
+	"github.com/matrix-org/dendrite/roomserver/types"
+)
+
+const eventStateKeysSchema = `
+	CREATE TABLE IF NOT EXISTS roomserver_event_state_keys (
+    event_state_key_nid INTEGER PRIMARY KEY AUTOINCREMENT,
+    event_state_key TEXT NOT NULL UNIQUE
+	);
+	INSERT INTO roomserver_event_state_keys (event_state_key_nid, event_state_key)
+		VALUES (1, '')
+		ON CONFLICT DO NOTHING;
+`
+
+// Same as insertEventTypeNIDSQL
+const insertEventStateKeyNIDSQL = `
+	INSERT INTO roomserver_event_state_keys (event_state_key) VALUES ($1)
+	  ON CONFLICT DO NOTHING;
+`
+
+const selectEventStateKeyNIDSQL = `
+	SELECT event_state_key_nid FROM roomserver_event_state_keys
+	  WHERE event_state_key = $1
+`
+
+// Bulk lookup from string state key to numeric ID for that state key.
+// Takes an array of strings as the query parameter.
+const bulkSelectEventStateKeySQL = `
+	SELECT event_state_key, event_state_key_nid FROM roomserver_event_state_keys
+	  WHERE event_state_key IN ($1)
+`
+
+// Bulk lookup from numeric ID to string state key for that state key.
+// Takes an array of strings as the query parameter.
+const bulkSelectEventStateKeyNIDSQL = `
+	SELECT event_state_key, event_state_key_nid FROM roomserver_event_state_keys
+	  WHERE event_state_key_nid IN ($1)
+`
+
+type eventStateKeyStatements struct {
+	db                             *sql.DB
+	insertEventStateKeyNIDStmt     *sql.Stmt
+	selectEventStateKeyNIDStmt     *sql.Stmt
+	bulkSelectEventStateKeyNIDStmt *sql.Stmt
+	bulkSelectEventStateKeyStmt    *sql.Stmt
+}
+
+func NewSqliteEventStateKeysTable(db *sql.DB) (tables.EventStateKeys, error) {
+	s := &eventStateKeyStatements{
+		db: db,
+	}
+	_, err := db.Exec(eventStateKeysSchema)
+	if err != nil {
+		return nil, err
+	}
+	return s, shared.StatementList{
+		{&s.insertEventStateKeyNIDStmt, insertEventStateKeyNIDSQL},
+		{&s.selectEventStateKeyNIDStmt, selectEventStateKeyNIDSQL},
+		{&s.bulkSelectEventStateKeyNIDStmt, bulkSelectEventStateKeyNIDSQL},
+		{&s.bulkSelectEventStateKeyStmt, bulkSelectEventStateKeySQL},
+	}.Prepare(db)
+}
+
+func (s *eventStateKeyStatements) InsertEventStateKeyNID(
+	ctx context.Context, txn *sql.Tx, eventStateKey string,
+) (types.EventStateKeyNID, error) {
+	insertStmt := sqlutil.TxStmt(txn, s.insertEventStateKeyNIDStmt)
+	res, err := insertStmt.ExecContext(ctx, eventStateKey)
+	if err != nil {
+		return 0, err
+	}
+	eventStateKeyNID, err := res.LastInsertId()
+	if err != nil {
+		return 0, err
+	}
+	return types.EventStateKeyNID(eventStateKeyNID), err
+}
+
+func (s *eventStateKeyStatements) SelectEventStateKeyNID(
+	ctx context.Context, txn *sql.Tx, eventStateKey string,
+) (types.EventStateKeyNID, error) {
+	var eventStateKeyNID int64
+	stmt := sqlutil.TxStmt(txn, s.selectEventStateKeyNIDStmt)
+	err := stmt.QueryRowContext(ctx, eventStateKey).Scan(&eventStateKeyNID)
+	return types.EventStateKeyNID(eventStateKeyNID), err
+}
+
+func (s *eventStateKeyStatements) BulkSelectEventStateKeyNID(
+	ctx context.Context, eventStateKeys []string,
+) (map[string]types.EventStateKeyNID, error) {
+	iEventStateKeys := make([]interface{}, len(eventStateKeys))
+	for k, v := range eventStateKeys {
+		iEventStateKeys[k] = v
+	}
+	selectOrig := strings.Replace(bulkSelectEventStateKeySQL, "($1)", sqlutil.QueryVariadic(len(eventStateKeys)), 1)
+
+	rows, err := s.db.QueryContext(ctx, selectOrig, iEventStateKeys...)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "bulkSelectEventStateKeyNID: rows.close() failed")
+	result := make(map[string]types.EventStateKeyNID, len(eventStateKeys))
+	for rows.Next() {
+		var stateKey string
+		var stateKeyNID int64
+		if err := rows.Scan(&stateKey, &stateKeyNID); err != nil {
+			return nil, err
+		}
+		result[stateKey] = types.EventStateKeyNID(stateKeyNID)
+	}
+	return result, nil
+}
+
+func (s *eventStateKeyStatements) BulkSelectEventStateKey(
+	ctx context.Context, eventStateKeyNIDs []types.EventStateKeyNID,
+) (map[types.EventStateKeyNID]string, error) {
+	iEventStateKeyNIDs := make([]interface{}, len(eventStateKeyNIDs))
+	for k, v := range eventStateKeyNIDs {
+		iEventStateKeyNIDs[k] = v
+	}
+	selectOrig := strings.Replace(bulkSelectEventStateKeyNIDSQL, "($1)", sqlutil.QueryVariadic(len(eventStateKeyNIDs)), 1)
+
+	rows, err := s.db.QueryContext(ctx, selectOrig, iEventStateKeyNIDs...)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "bulkSelectEventStateKey: rows.close() failed")
+	result := make(map[types.EventStateKeyNID]string, len(eventStateKeyNIDs))
+	for rows.Next() {
+		var stateKey string
+		var stateKeyNID int64
+		if err := rows.Scan(&stateKey, &stateKeyNID); err != nil {
+			return nil, err
+		}
+		result[types.EventStateKeyNID(stateKeyNID)] = stateKey
+	}
+	return result, nil
+}

roomserver/storage/cosmosdb/event_types_table.go

@@ -0,0 +1,161 @@
+// Copyright 2017-2018 New Vector Ltd
+// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+	"strings"
+
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/roomserver/storage/shared"
+	"github.com/matrix-org/dendrite/roomserver/storage/tables"
+	"github.com/matrix-org/dendrite/roomserver/types"
+)
+
+const eventTypesSchema = `
+  CREATE TABLE IF NOT EXISTS roomserver_event_types (
+    event_type_nid INTEGER PRIMARY KEY AUTOINCREMENT,
+    event_type TEXT NOT NULL UNIQUE
+  );
+  INSERT INTO roomserver_event_types (event_type_nid, event_type) VALUES
+    (1, 'm.room.create'),
+    (2, 'm.room.power_levels'),
+    (3, 'm.room.join_rules'),
+    (4, 'm.room.third_party_invite'),
+    (5, 'm.room.member'),
+    (6, 'm.room.redaction'),
+    (7, 'm.room.history_visibility') ON CONFLICT DO NOTHING;
+`
+
+// Assign a new numeric event type ID.
+// The usual case is that the event type is not in the database.
+// In that case the ID will be assigned using the next value from the sequence.
+// We use `RETURNING` to tell postgres to return the assigned ID.
+// But it's possible that the type was added in a query that raced with us.
+// This will result in a conflict on the event_type_unique constraint, in this
+// case we do nothing. Postgresql won't return a row in that case so we rely on
+// the caller catching the sql.ErrNoRows error and running a select to get the row.
+// We could get postgresql to return the row on a conflict by updating the row
+// but it doesn't seem like a good idea to modify the rows just to make postgresql
+// return it. Modifying the rows will cause postgres to assign a new tuple for the
+// row even though the data doesn't change resulting in unncesssary modifications
+// to the indexes.
+const insertEventTypeNIDSQL = `
+	INSERT INTO roomserver_event_types (event_type) VALUES ($1)
+	  ON CONFLICT DO NOTHING;
+`
+
+const insertEventTypeNIDResultSQL = `
+	SELECT event_type_nid FROM roomserver_event_types
+		WHERE rowid = last_insert_rowid();
+`
+
+const selectEventTypeNIDSQL = `
+	SELECT event_type_nid FROM roomserver_event_types WHERE event_type = $1
+`
+
+// Bulk lookup from string event type to numeric ID for that event type.
+// Takes an array of strings as the query parameter.
+const bulkSelectEventTypeNIDSQL = `
+	SELECT event_type, event_type_nid FROM roomserver_event_types
+	  WHERE event_type IN ($1)
+`
+
+type eventTypeStatements struct {
+	db                           *sql.DB
+	insertEventTypeNIDStmt       *sql.Stmt
+	insertEventTypeNIDResultStmt *sql.Stmt
+	selectEventTypeNIDStmt       *sql.Stmt
+	bulkSelectEventTypeNIDStmt   *sql.Stmt
+}
+
+func NewSqliteEventTypesTable(db *sql.DB) (tables.EventTypes, error) {
+	s := &eventTypeStatements{
+		db: db,
+	}
+	_, err := db.Exec(eventTypesSchema)
+	if err != nil {
+		return nil, err
+	}
+
+	return s, shared.StatementList{
+		{&s.insertEventTypeNIDStmt, insertEventTypeNIDSQL},
+		{&s.insertEventTypeNIDResultStmt, insertEventTypeNIDResultSQL},
+		{&s.selectEventTypeNIDStmt, selectEventTypeNIDSQL},
+		{&s.bulkSelectEventTypeNIDStmt, bulkSelectEventTypeNIDSQL},
+	}.Prepare(db)
+}
+
+func (s *eventTypeStatements) InsertEventTypeNID(
+	ctx context.Context, txn *sql.Tx, eventType string,
+) (types.EventTypeNID, error) {
+	var eventTypeNID int64
+	insertStmt := sqlutil.TxStmt(txn, s.insertEventTypeNIDStmt)
+	resultStmt := sqlutil.TxStmt(txn, s.insertEventTypeNIDResultStmt)
+	_, err := insertStmt.ExecContext(ctx, eventType)
+	if err != nil {
+		return 0, fmt.Errorf("insertStmt.ExecContext: %w", err)
+	}
+	if err = resultStmt.QueryRowContext(ctx).Scan(&eventTypeNID); err != nil {
+		return 0, fmt.Errorf("resultStmt.QueryRowContext.Scan: %w", err)
+	}
+	return types.EventTypeNID(eventTypeNID), err
+}
+
+func (s *eventTypeStatements) SelectEventTypeNID(
+	ctx context.Context, tx *sql.Tx, eventType string,
+) (types.EventTypeNID, error) {
+	var eventTypeNID int64
+	selectStmt := sqlutil.TxStmt(tx, s.selectEventTypeNIDStmt)
+	err := selectStmt.QueryRowContext(ctx, eventType).Scan(&eventTypeNID)
+	return types.EventTypeNID(eventTypeNID), err
+}
+
+func (s *eventTypeStatements) BulkSelectEventTypeNID(
+	ctx context.Context, eventTypes []string,
+) (map[string]types.EventTypeNID, error) {
+	///////////////
+	iEventTypes := make([]interface{}, len(eventTypes))
+	for k, v := range eventTypes {
+		iEventTypes[k] = v
+	}
+	selectOrig := strings.Replace(bulkSelectEventTypeNIDSQL, "($1)", sqlutil.QueryVariadic(len(iEventTypes)), 1)
+	selectPrep, err := s.db.Prepare(selectOrig)
+	if err != nil {
+		return nil, err
+	}
+	///////////////
+
+	rows, err := selectPrep.QueryContext(ctx, iEventTypes...)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "bulkSelectEventTypeNID: rows.close() failed")
+
+	result := make(map[string]types.EventTypeNID, len(eventTypes))
+	for rows.Next() {
+		var eventType string
+		var eventTypeNID int64
+		if err := rows.Scan(&eventType, &eventTypeNID); err != nil {
+			return nil, err
+		}
+		result[eventType] = types.EventTypeNID(eventTypeNID)
+	}
+	return result, nil
+}

roomserver/storage/cosmosdb/events_table.go

@@ -0,0 +1,515 @@
+// Copyright 2017-2018 New Vector Ltd
+// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+	"encoding/json"
+	"fmt"
+	"strings"
+
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/roomserver/storage/shared"
+	"github.com/matrix-org/dendrite/roomserver/storage/tables"
+	"github.com/matrix-org/dendrite/roomserver/types"
+	"github.com/matrix-org/gomatrixserverlib"
+)
+
+const eventsSchema = `
+  CREATE TABLE IF NOT EXISTS roomserver_events (
+    event_nid INTEGER PRIMARY KEY AUTOINCREMENT,
+    room_nid INTEGER NOT NULL,
+    event_type_nid INTEGER NOT NULL,
+    event_state_key_nid INTEGER NOT NULL,
+    sent_to_output BOOLEAN NOT NULL DEFAULT FALSE,
+    state_snapshot_nid INTEGER NOT NULL DEFAULT 0,
+    depth INTEGER NOT NULL,
+    event_id TEXT NOT NULL UNIQUE,
+    reference_sha256 BLOB NOT NULL,
+	auth_event_nids TEXT NOT NULL DEFAULT '[]',
+	is_rejected BOOLEAN NOT NULL DEFAULT FALSE
+  );
+`
+
+const insertEventSQL = `
+	INSERT INTO roomserver_events (room_nid, event_type_nid, event_state_key_nid, event_id, reference_sha256, auth_event_nids, depth, is_rejected)
+	  VALUES ($1, $2, $3, $4, $5, $6, $7, $8)
+	  ON CONFLICT DO NOTHING;
+`
+
+const selectEventSQL = "" +
+	"SELECT event_nid, state_snapshot_nid FROM roomserver_events WHERE event_id = $1"
+
+// Bulk lookup of events by string ID.
+// Sort by the numeric IDs for event type and state key.
+// This means we can use binary search to lookup entries by type and state key.
+const bulkSelectStateEventByIDSQL = "" +
+	"SELECT event_type_nid, event_state_key_nid, event_nid FROM roomserver_events" +
+	" WHERE event_id IN ($1)" +
+	" ORDER BY event_type_nid, event_state_key_nid ASC"
+
+const bulkSelectStateAtEventByIDSQL = "" +
+	"SELECT event_type_nid, event_state_key_nid, event_nid, state_snapshot_nid, is_rejected FROM roomserver_events" +
+	" WHERE event_id IN ($1)"
+
+const updateEventStateSQL = "" +
+	"UPDATE roomserver_events SET state_snapshot_nid = $1 WHERE event_nid = $2"
+
+const selectEventSentToOutputSQL = "" +
+	"SELECT sent_to_output FROM roomserver_events WHERE event_nid = $1"
+
+const updateEventSentToOutputSQL = "" +
+	"UPDATE roomserver_events SET sent_to_output = TRUE WHERE event_nid = $1"
+
+const selectEventIDSQL = "" +
+	"SELECT event_id FROM roomserver_events WHERE event_nid = $1"
+
+const bulkSelectStateAtEventAndReferenceSQL = "" +
+	"SELECT event_type_nid, event_state_key_nid, event_nid, state_snapshot_nid, event_id, reference_sha256" +
+	" FROM roomserver_events WHERE event_nid IN ($1)"
+
+const bulkSelectEventReferenceSQL = "" +
+	"SELECT event_id, reference_sha256 FROM roomserver_events WHERE event_nid IN ($1)"
+
+const bulkSelectEventIDSQL = "" +
+	"SELECT event_nid, event_id FROM roomserver_events WHERE event_nid IN ($1)"
+
+const bulkSelectEventNIDSQL = "" +
+	"SELECT event_id, event_nid FROM roomserver_events WHERE event_id IN ($1)"
+
+const selectMaxEventDepthSQL = "" +
+	"SELECT COALESCE(MAX(depth) + 1, 0) FROM roomserver_events WHERE event_nid IN ($1)"
+
+const selectRoomNIDsForEventNIDsSQL = "" +
+	"SELECT event_nid, room_nid FROM roomserver_events WHERE event_nid IN ($1)"
+
+type eventStatements struct {
+	db                                     *sql.DB
+	insertEventStmt                        *sql.Stmt
+	selectEventStmt                        *sql.Stmt
+	bulkSelectStateEventByIDStmt           *sql.Stmt
+	bulkSelectStateAtEventByIDStmt         *sql.Stmt
+	updateEventStateStmt                   *sql.Stmt
+	selectEventSentToOutputStmt            *sql.Stmt
+	updateEventSentToOutputStmt            *sql.Stmt
+	selectEventIDStmt                      *sql.Stmt
+	bulkSelectStateAtEventAndReferenceStmt *sql.Stmt
+	bulkSelectEventReferenceStmt           *sql.Stmt
+	bulkSelectEventIDStmt                  *sql.Stmt
+	bulkSelectEventNIDStmt                 *sql.Stmt
+	//selectRoomNIDsForEventNIDsStmt           *sql.Stmt
+}
+
+func NewSqliteEventsTable(db *sql.DB) (tables.Events, error) {
+	s := &eventStatements{
+		db: db,
+	}
+	_, err := db.Exec(eventsSchema)
+	if err != nil {
+		return nil, err
+	}
+
+	return s, shared.StatementList{
+		{&s.insertEventStmt, insertEventSQL},
+		{&s.selectEventStmt, selectEventSQL},
+		{&s.bulkSelectStateEventByIDStmt, bulkSelectStateEventByIDSQL},
+		{&s.bulkSelectStateAtEventByIDStmt, bulkSelectStateAtEventByIDSQL},
+		{&s.updateEventStateStmt, updateEventStateSQL},
+		{&s.updateEventSentToOutputStmt, updateEventSentToOutputSQL},
+		{&s.selectEventSentToOutputStmt, selectEventSentToOutputSQL},
+		{&s.selectEventIDStmt, selectEventIDSQL},
+		{&s.bulkSelectStateAtEventAndReferenceStmt, bulkSelectStateAtEventAndReferenceSQL},
+		{&s.bulkSelectEventReferenceStmt, bulkSelectEventReferenceSQL},
+		{&s.bulkSelectEventIDStmt, bulkSelectEventIDSQL},
+		{&s.bulkSelectEventNIDStmt, bulkSelectEventNIDSQL},
+		//{&s.selectRoomNIDForEventNIDStmt, selectRoomNIDForEventNIDSQL},
+	}.Prepare(db)
+}
+
+func (s *eventStatements) InsertEvent(
+	ctx context.Context,
+	txn *sql.Tx,
+	roomNID types.RoomNID,
+	eventTypeNID types.EventTypeNID,
+	eventStateKeyNID types.EventStateKeyNID,
+	eventID string,
+	referenceSHA256 []byte,
+	authEventNIDs []types.EventNID,
+	depth int64,
+	isRejected bool,
+) (types.EventNID, types.StateSnapshotNID, error) {
+	// attempt to insert: the last_row_id is the event NID
+	var eventNID int64
+	insertStmt := sqlutil.TxStmt(txn, s.insertEventStmt)
+	result, err := insertStmt.ExecContext(
+		ctx, int64(roomNID), int64(eventTypeNID), int64(eventStateKeyNID),
+		eventID, referenceSHA256, eventNIDsAsArray(authEventNIDs), depth, isRejected,
+	)
+	if err != nil {
+		return 0, 0, err
+	}
+	modified, err := result.RowsAffected()
+	if modified == 0 && err == nil {
+		return 0, 0, sql.ErrNoRows
+	}
+	eventNID, err = result.LastInsertId()
+	return types.EventNID(eventNID), 0, err
+}
+
+func (s *eventStatements) SelectEvent(
+	ctx context.Context, txn *sql.Tx, eventID string,
+) (types.EventNID, types.StateSnapshotNID, error) {
+	var eventNID int64
+	var stateNID int64
+	selectStmt := sqlutil.TxStmt(txn, s.selectEventStmt)
+	err := selectStmt.QueryRowContext(ctx, eventID).Scan(&eventNID, &stateNID)
+	return types.EventNID(eventNID), types.StateSnapshotNID(stateNID), err
+}
+
+// bulkSelectStateEventByID lookups a list of state events by event ID.
+// If any of the requested events are missing from the database it returns a types.MissingEventError
+func (s *eventStatements) BulkSelectStateEventByID(
+	ctx context.Context, eventIDs []string,
+) ([]types.StateEntry, error) {
+	///////////////
+	iEventIDs := make([]interface{}, len(eventIDs))
+	for k, v := range eventIDs {
+		iEventIDs[k] = v
+	}
+	selectOrig := strings.Replace(bulkSelectStateEventByIDSQL, "($1)", sqlutil.QueryVariadic(len(iEventIDs)), 1)
+	selectStmt, err := s.db.Prepare(selectOrig)
+	if err != nil {
+		return nil, err
+	}
+	///////////////
+
+	rows, err := selectStmt.QueryContext(ctx, iEventIDs...)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "bulkSelectStateEventByID: rows.close() failed")
+	// We know that we will only get as many results as event IDs
+	// because of the unique constraint on event IDs.
+	// So we can allocate an array of the correct size now.
+	// We might get fewer results than IDs so we adjust the length of the slice before returning it.
+	results := make([]types.StateEntry, len(eventIDs))
+	i := 0
+	for ; rows.Next(); i++ {
+		result := &results[i]
+		if err = rows.Scan(
+			&result.EventTypeNID,
+			&result.EventStateKeyNID,
+			&result.EventNID,
+		); err != nil {
+			return nil, err
+		}
+	}
+	if i != len(eventIDs) {
+		// If there are fewer rows returned than IDs then we were asked to lookup event IDs we don't have.
+		// We don't know which ones were missing because we don't return the string IDs in the query.
+		// However it should be possible debug this by replaying queries or entries from the input kafka logs.
+		// If this turns out to be impossible and we do need the debug information here, it would be better
+		// to do it as a separate query rather than slowing down/complicating the internal case.
+		return nil, types.MissingEventError(
+			fmt.Sprintf("storage: state event IDs missing from the database (%d != %d)", i, len(eventIDs)),
+		)
+	}
+	return results, err
+}
+
+// bulkSelectStateAtEventByID lookups the state at a list of events by event ID.
+// If any of the requested events are missing from the database it returns a types.MissingEventError.
+// If we do not have the state for any of the requested events it returns a types.MissingEventError.
+func (s *eventStatements) BulkSelectStateAtEventByID(
+	ctx context.Context, eventIDs []string,
+) ([]types.StateAtEvent, error) {
+	///////////////
+	iEventIDs := make([]interface{}, len(eventIDs))
+	for k, v := range eventIDs {
+		iEventIDs[k] = v
+	}
+	selectOrig := strings.Replace(bulkSelectStateAtEventByIDSQL, "($1)", sqlutil.QueryVariadic(len(iEventIDs)), 1)
+	selectStmt, err := s.db.Prepare(selectOrig)
+	if err != nil {
+		return nil, err
+	}
+	///////////////
+	rows, err := selectStmt.QueryContext(ctx, iEventIDs...)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "bulkSelectStateAtEventByID: rows.close() failed")
+	results := make([]types.StateAtEvent, len(eventIDs))
+	i := 0
+	for ; rows.Next(); i++ {
+		result := &results[i]
+		if err = rows.Scan(
+			&result.EventTypeNID,
+			&result.EventStateKeyNID,
+			&result.EventNID,
+			&result.BeforeStateSnapshotNID,
+			&result.IsRejected,
+		); err != nil {
+			return nil, err
+		}
+		if result.BeforeStateSnapshotNID == 0 {
+			return nil, types.MissingEventError(
+				fmt.Sprintf("storage: missing state for event NID %d", result.EventNID),
+			)
+		}
+	}
+	if i != len(eventIDs) {
+		return nil, types.MissingEventError(
+			fmt.Sprintf("storage: event IDs missing from the database (%d != %d)", i, len(eventIDs)),
+		)
+	}
+	return results, err
+}
+
+func (s *eventStatements) UpdateEventState(
+	ctx context.Context, txn *sql.Tx, eventNID types.EventNID, stateNID types.StateSnapshotNID,
+) error {
+	stmt := sqlutil.TxStmt(txn, s.updateEventStateStmt)
+	_, err := stmt.ExecContext(ctx, int64(stateNID), int64(eventNID))
+	return err
+}
+
+func (s *eventStatements) SelectEventSentToOutput(
+	ctx context.Context, txn *sql.Tx, eventNID types.EventNID,
+) (sentToOutput bool, err error) {
+	selectStmt := sqlutil.TxStmt(txn, s.selectEventSentToOutputStmt)
+	err = selectStmt.QueryRowContext(ctx, int64(eventNID)).Scan(&sentToOutput)
+	return
+}
+
+func (s *eventStatements) UpdateEventSentToOutput(ctx context.Context, txn *sql.Tx, eventNID types.EventNID) error {
+	updateStmt := sqlutil.TxStmt(txn, s.updateEventSentToOutputStmt)
+	_, err := updateStmt.ExecContext(ctx, int64(eventNID))
+	return err
+}
+
+func (s *eventStatements) SelectEventID(
+	ctx context.Context, txn *sql.Tx, eventNID types.EventNID,
+) (eventID string, err error) {
+	selectStmt := sqlutil.TxStmt(txn, s.selectEventIDStmt)
+	err = selectStmt.QueryRowContext(ctx, int64(eventNID)).Scan(&eventID)
+	return
+}
+
+func (s *eventStatements) BulkSelectStateAtEventAndReference(
+	ctx context.Context, txn *sql.Tx, eventNIDs []types.EventNID,
+) ([]types.StateAtEventAndReference, error) {
+	///////////////
+	iEventNIDs := make([]interface{}, len(eventNIDs))
+	for k, v := range eventNIDs {
+		iEventNIDs[k] = v
+	}
+	selectOrig := strings.Replace(bulkSelectStateAtEventAndReferenceSQL, "($1)", sqlutil.QueryVariadic(len(iEventNIDs)), 1)
+	selectPrep, err := s.db.Prepare(selectOrig)
+	if err != nil {
+		return nil, err
+	}
+	//////////////
+
+	rows, err := sqlutil.TxStmt(txn, selectPrep).QueryContext(ctx, iEventNIDs...)
+	if err != nil {
+		return nil, fmt.Errorf("sqlutil.TxStmt.QueryContext: %w", err)
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "bulkSelectStateAtEventAndReference: rows.close() failed")
+	results := make([]types.StateAtEventAndReference, len(eventNIDs))
+	i := 0
+	for ; rows.Next(); i++ {
+		var (
+			eventTypeNID     int64
+			eventStateKeyNID int64
+			eventNID         int64
+			stateSnapshotNID int64
+			eventID          string
+			eventSHA256      []byte
+		)
+		if err = rows.Scan(
+			&eventTypeNID, &eventStateKeyNID, &eventNID, &stateSnapshotNID, &eventID, &eventSHA256,
+		); err != nil {
+			return nil, err
+		}
+		result := &results[i]
+		result.EventTypeNID = types.EventTypeNID(eventTypeNID)
+		result.EventStateKeyNID = types.EventStateKeyNID(eventStateKeyNID)
+		result.EventNID = types.EventNID(eventNID)
+		result.BeforeStateSnapshotNID = types.StateSnapshotNID(stateSnapshotNID)
+		result.EventID = eventID
+		result.EventSHA256 = eventSHA256
+	}
+	if i != len(eventNIDs) {
+		return nil, fmt.Errorf("storage: event NIDs missing from the database (%d != %d)", i, len(eventNIDs))
+	}
+	return results, nil
+}
+
+func (s *eventStatements) BulkSelectEventReference(
+	ctx context.Context, txn *sql.Tx, eventNIDs []types.EventNID,
+) ([]gomatrixserverlib.EventReference, error) {
+	///////////////
+	iEventNIDs := make([]interface{}, len(eventNIDs))
+	for k, v := range eventNIDs {
+		iEventNIDs[k] = v
+	}
+	selectOrig := strings.Replace(bulkSelectEventReferenceSQL, "($1)", sqlutil.QueryVariadic(len(iEventNIDs)), 1)
+	selectPrep, err := s.db.Prepare(selectOrig)
+	if err != nil {
+		return nil, err
+	}
+	///////////////
+
+	selectStmt := sqlutil.TxStmt(txn, selectPrep)
+	rows, err := selectStmt.QueryContext(ctx, iEventNIDs...)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "bulkSelectEventReference: rows.close() failed")
+	results := make([]gomatrixserverlib.EventReference, len(eventNIDs))
+	i := 0
+	for ; rows.Next(); i++ {
+		result := &results[i]
+		if err = rows.Scan(&result.EventID, &result.EventSHA256); err != nil {
+			return nil, err
+		}
+	}
+	if i != len(eventNIDs) {
+		return nil, fmt.Errorf("storage: event NIDs missing from the database (%d != %d)", i, len(eventNIDs))
+	}
+	return results, nil
+}
+
+// bulkSelectEventID returns a map from numeric event ID to string event ID.
+func (s *eventStatements) BulkSelectEventID(ctx context.Context, eventNIDs []types.EventNID) (map[types.EventNID]string, error) {
+	///////////////
+	iEventNIDs := make([]interface{}, len(eventNIDs))
+	for k, v := range eventNIDs {
+		iEventNIDs[k] = v
+	}
+	selectOrig := strings.Replace(bulkSelectEventIDSQL, "($1)", sqlutil.QueryVariadic(len(iEventNIDs)), 1)
+	selectStmt, err := s.db.Prepare(selectOrig)
+	if err != nil {
+		return nil, err
+	}
+	///////////////
+
+	rows, err := selectStmt.QueryContext(ctx, iEventNIDs...)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "bulkSelectEventID: rows.close() failed")
+	results := make(map[types.EventNID]string, len(eventNIDs))
+	i := 0
+	for ; rows.Next(); i++ {
+		var eventNID int64
+		var eventID string
+		if err = rows.Scan(&eventNID, &eventID); err != nil {
+			return nil, err
+		}
+		results[types.EventNID(eventNID)] = eventID
+	}
+	if i != len(eventNIDs) {
+		return nil, fmt.Errorf("storage: event NIDs missing from the database (%d != %d)", i, len(eventNIDs))
+	}
+	return results, nil
+}
+
+// bulkSelectEventNIDs returns a map from string event ID to numeric event ID.
+// If an event ID is not in the database then it is omitted from the map.
+func (s *eventStatements) BulkSelectEventNID(ctx context.Context, eventIDs []string) (map[string]types.EventNID, error) {
+	///////////////
+	iEventIDs := make([]interface{}, len(eventIDs))
+	for k, v := range eventIDs {
+		iEventIDs[k] = v
+	}
+	selectOrig := strings.Replace(bulkSelectEventNIDSQL, "($1)", sqlutil.QueryVariadic(len(iEventIDs)), 1)
+	selectStmt, err := s.db.Prepare(selectOrig)
+	if err != nil {
+		return nil, err
+	}
+	///////////////
+	rows, err := selectStmt.QueryContext(ctx, iEventIDs...)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "bulkSelectEventNID: rows.close() failed")
+	results := make(map[string]types.EventNID, len(eventIDs))
+	for rows.Next() {
+		var eventID string
+		var eventNID int64
+		if err = rows.Scan(&eventID, &eventNID); err != nil {
+			return nil, err
+		}
+		results[eventID] = types.EventNID(eventNID)
+	}
+	return results, nil
+}
+
+func (s *eventStatements) SelectMaxEventDepth(ctx context.Context, txn *sql.Tx, eventNIDs []types.EventNID) (int64, error) {
+	var result int64
+	iEventIDs := make([]interface{}, len(eventNIDs))
+	for i, v := range eventNIDs {
+		iEventIDs[i] = v
+	}
+	sqlStr := strings.Replace(selectMaxEventDepthSQL, "($1)", sqlutil.QueryVariadic(len(iEventIDs)), 1)
+	sqlPrep, err := s.db.Prepare(sqlStr)
+	if err != nil {
+		return 0, err
+	}
+	err = sqlutil.TxStmt(txn, sqlPrep).QueryRowContext(ctx, iEventIDs...).Scan(&result)
+	if err != nil {
+		return 0, fmt.Errorf("sqlutil.TxStmt.QueryRowContext: %w", err)
+	}
+	return result, nil
+}
+
+func (s *eventStatements) SelectRoomNIDsForEventNIDs(
+	ctx context.Context, eventNIDs []types.EventNID,
+) (map[types.EventNID]types.RoomNID, error) {
+	sqlStr := strings.Replace(selectRoomNIDsForEventNIDsSQL, "($1)", sqlutil.QueryVariadic(len(eventNIDs)), 1)
+	sqlPrep, err := s.db.Prepare(sqlStr)
+	if err != nil {
+		return nil, err
+	}
+	iEventNIDs := make([]interface{}, len(eventNIDs))
+	for i, v := range eventNIDs {
+		iEventNIDs[i] = v
+	}
+	rows, err := sqlPrep.QueryContext(ctx, iEventNIDs...)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "selectRoomNIDsForEventNIDsStmt: rows.close() failed")
+	result := make(map[types.EventNID]types.RoomNID)
+	for rows.Next() {
+		var eventNID types.EventNID
+		var roomNID types.RoomNID
+		if err = rows.Scan(&eventNID, &roomNID); err != nil {
+			return nil, err
+		}
+		result[eventNID] = roomNID
+	}
+	return result, nil
+}
+
+func eventNIDsAsArray(eventNIDs []types.EventNID) string {
+	b, _ := json.Marshal(eventNIDs)
+	return string(b)
+}

roomserver/storage/cosmosdb/invite_table.go

@@ -0,0 +1,159 @@
+// Copyright 2017-2018 New Vector Ltd
+// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/roomserver/storage/shared"
+	"github.com/matrix-org/dendrite/roomserver/storage/tables"
+	"github.com/matrix-org/dendrite/roomserver/types"
+)
+
+const inviteSchema = `
+	CREATE TABLE IF NOT EXISTS roomserver_invites (
+		invite_event_id TEXT PRIMARY KEY,
+		room_nid INTEGER NOT NULL,
+		target_nid INTEGER NOT NULL,
+		sender_nid INTEGER NOT NULL DEFAULT 0,
+		retired BOOLEAN NOT NULL DEFAULT FALSE,
+		invite_event_json TEXT NOT NULL
+	);
+
+	CREATE INDEX IF NOT EXISTS roomserver_invites_active_idx ON roomserver_invites (target_nid, room_nid)
+		WHERE NOT retired;
+`
+const insertInviteEventSQL = "" +
+	"INSERT INTO roomserver_invites (invite_event_id, room_nid, target_nid," +
+	" sender_nid, invite_event_json) VALUES ($1, $2, $3, $4, $5)" +
+	" ON CONFLICT DO NOTHING"
+
+const selectInviteActiveForUserInRoomSQL = "" +
+	"SELECT invite_event_id, sender_nid FROM roomserver_invites" +
+	" WHERE target_nid = $1 AND room_nid = $2" +
+	" AND NOT retired"
+
+// Retire every active invite for a user in a room.
+// Ideally we'd know which invite events were retired by a given update so we
+// wouldn't need to remove every active invite.
+// However the matrix protocol doesn't give us a way to reliably identify the
+// invites that were retired, so we are forced to retire all of them.
+const updateInviteRetiredSQL = `
+	UPDATE roomserver_invites SET retired = TRUE WHERE room_nid = $1 AND target_nid = $2 AND NOT retired
+`
+
+const selectInvitesAboutToRetireSQL = `
+SELECT invite_event_id FROM roomserver_invites WHERE room_nid = $1 AND target_nid = $2 AND NOT retired
+`
+
+type inviteStatements struct {
+	db                                  *sql.DB
+	insertInviteEventStmt               *sql.Stmt
+	selectInviteActiveForUserInRoomStmt *sql.Stmt
+	updateInviteRetiredStmt             *sql.Stmt
+	selectInvitesAboutToRetireStmt      *sql.Stmt
+}
+
+func NewSqliteInvitesTable(db *sql.DB) (tables.Invites, error) {
+	s := &inviteStatements{
+		db: db,
+	}
+	_, err := db.Exec(inviteSchema)
+	if err != nil {
+		return nil, err
+	}
+
+	return s, shared.StatementList{
+		{&s.insertInviteEventStmt, insertInviteEventSQL},
+		{&s.selectInviteActiveForUserInRoomStmt, selectInviteActiveForUserInRoomSQL},
+		{&s.updateInviteRetiredStmt, updateInviteRetiredSQL},
+		{&s.selectInvitesAboutToRetireStmt, selectInvitesAboutToRetireSQL},
+	}.Prepare(db)
+}
+
+func (s *inviteStatements) InsertInviteEvent(
+	ctx context.Context,
+	txn *sql.Tx, inviteEventID string, roomNID types.RoomNID,
+	targetUserNID, senderUserNID types.EventStateKeyNID,
+	inviteEventJSON []byte,
+) (bool, error) {
+	var count int64
+	stmt := sqlutil.TxStmt(txn, s.insertInviteEventStmt)
+	result, err := stmt.ExecContext(
+		ctx, inviteEventID, roomNID, targetUserNID, senderUserNID, inviteEventJSON,
+	)
+	if err != nil {
+		return false, err
+	}
+	count, err = result.RowsAffected()
+	if err != nil {
+		return false, err
+	}
+	return count != 0, err
+}
+
+func (s *inviteStatements) UpdateInviteRetired(
+	ctx context.Context,
+	txn *sql.Tx, roomNID types.RoomNID, targetUserNID types.EventStateKeyNID,
+) (eventIDs []string, err error) {
+	// gather all the event IDs we will retire
+	stmt := sqlutil.TxStmt(txn, s.selectInvitesAboutToRetireStmt)
+	rows, err := stmt.QueryContext(ctx, roomNID, targetUserNID)
+	if err != nil {
+		return
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "UpdateInviteRetired: rows.close() failed")
+	for rows.Next() {
+		var inviteEventID string
+		if err = rows.Scan(&inviteEventID); err != nil {
+			return
+		}
+		eventIDs = append(eventIDs, inviteEventID)
+	}
+	// now retire the invites
+	stmt = sqlutil.TxStmt(txn, s.updateInviteRetiredStmt)
+	_, err = stmt.ExecContext(ctx, roomNID, targetUserNID)
+	return
+}
+
+// selectInviteActiveForUserInRoom returns a list of sender state key NIDs
+func (s *inviteStatements) SelectInviteActiveForUserInRoom(
+	ctx context.Context,
+	targetUserNID types.EventStateKeyNID, roomNID types.RoomNID,
+) ([]types.EventStateKeyNID, []string, error) {
+	rows, err := s.selectInviteActiveForUserInRoomStmt.QueryContext(
+		ctx, targetUserNID, roomNID,
+	)
+	if err != nil {
+		return nil, nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "selectInviteActiveForUserInRoom: rows.close() failed")
+	var result []types.EventStateKeyNID
+	var eventIDs []string
+	for rows.Next() {
+		var eventID string
+		var senderUserNID int64
+		if err := rows.Scan(&eventID, &senderUserNID); err != nil {
+			return nil, nil, err
+		}
+		result = append(result, types.EventStateKeyNID(senderUserNID))
+		eventIDs = append(eventIDs, eventID)
+	}
+	return result, eventIDs, nil
+}

roomserver/storage/cosmosdb/membership_table.go

@@ -0,0 +1,306 @@
+// Copyright 2017-2018 New Vector Ltd
+// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+	"strings"
+
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/roomserver/storage/shared"
+	"github.com/matrix-org/dendrite/roomserver/storage/tables"
+	"github.com/matrix-org/dendrite/roomserver/types"
+)
+
+const membershipSchema = `
+	CREATE TABLE IF NOT EXISTS roomserver_membership (
+		room_nid INTEGER NOT NULL,
+		target_nid INTEGER NOT NULL,
+		sender_nid INTEGER NOT NULL DEFAULT 0,
+		membership_nid INTEGER NOT NULL DEFAULT 1,
+		event_nid INTEGER NOT NULL DEFAULT 0,
+		target_local BOOLEAN NOT NULL DEFAULT false,
+		forgotten BOOLEAN NOT NULL DEFAULT false,
+		UNIQUE (room_nid, target_nid)
+	);
+`
+
+var selectJoinedUsersSetForRoomsSQL = "" +
+	"SELECT target_nid, COUNT(room_nid) FROM roomserver_membership WHERE room_nid IN ($1) AND" +
+	" membership_nid = " + fmt.Sprintf("%d", tables.MembershipStateJoin) + " and forgotten = false" +
+	" GROUP BY target_nid"
+
+// Insert a row in to membership table so that it can be locked by the
+// SELECT FOR UPDATE
+const insertMembershipSQL = "" +
+	"INSERT INTO roomserver_membership (room_nid, target_nid, target_local)" +
+	" VALUES ($1, $2, $3)" +
+	" ON CONFLICT DO NOTHING"
+
+const selectMembershipFromRoomAndTargetSQL = "" +
+	"SELECT membership_nid, event_nid, forgotten FROM roomserver_membership" +
+	" WHERE room_nid = $1 AND target_nid = $2"
+
+const selectMembershipsFromRoomAndMembershipSQL = "" +
+	"SELECT event_nid FROM roomserver_membership" +
+	" WHERE room_nid = $1 AND membership_nid = $2 and forgotten = false"
+
+const selectLocalMembershipsFromRoomAndMembershipSQL = "" +
+	"SELECT event_nid FROM roomserver_membership" +
+	" WHERE room_nid = $1 AND membership_nid = $2" +
+	" AND target_local = true and forgotten = false"
+
+const selectMembershipsFromRoomSQL = "" +
+	"SELECT event_nid FROM roomserver_membership" +
+	" WHERE room_nid = $1 and forgotten = false"
+
+const selectLocalMembershipsFromRoomSQL = "" +
+	"SELECT event_nid FROM roomserver_membership" +
+	" WHERE room_nid = $1" +
+	" AND target_local = true and forgotten = false"
+
+const selectMembershipForUpdateSQL = "" +
+	"SELECT membership_nid FROM roomserver_membership" +
+	" WHERE room_nid = $1 AND target_nid = $2"
+
+const updateMembershipSQL = "" +
+	"UPDATE roomserver_membership SET sender_nid = $1, membership_nid = $2, event_nid = $3, forgotten = $4" +
+	" WHERE room_nid = $5 AND target_nid = $6"
+
+const updateMembershipForgetRoom = "" +
+	"UPDATE roomserver_membership SET forgotten = $1" +
+	" WHERE room_nid = $2 AND target_nid = $3"
+
+const selectRoomsWithMembershipSQL = "" +
+	"SELECT room_nid FROM roomserver_membership WHERE membership_nid = $1 AND target_nid = $2 and forgotten = false"
+
+// selectKnownUsersSQL uses a sub-select statement here to find rooms that the user is
+// joined to. Since this information is used to populate the user directory, we will
+// only return users that the user would ordinarily be able to see anyway.
+var selectKnownUsersSQL = "" +
+	"SELECT DISTINCT event_state_key FROM roomserver_membership INNER JOIN roomserver_event_state_keys ON " +
+	"roomserver_membership.target_nid = roomserver_event_state_keys.event_state_key_nid" +
+	" WHERE room_nid IN (" +
+	"  SELECT DISTINCT room_nid FROM roomserver_membership WHERE target_nid=$1 AND membership_nid = " + fmt.Sprintf("%d", tables.MembershipStateJoin) +
+	") AND membership_nid = " + fmt.Sprintf("%d", tables.MembershipStateJoin) + " AND event_state_key LIKE $2 LIMIT $3"
+
+type membershipStatements struct {
+	db                                              *sql.DB
+	insertMembershipStmt                            *sql.Stmt
+	selectMembershipForUpdateStmt                   *sql.Stmt
+	selectMembershipFromRoomAndTargetStmt           *sql.Stmt
+	selectMembershipsFromRoomAndMembershipStmt      *sql.Stmt
+	selectLocalMembershipsFromRoomAndMembershipStmt *sql.Stmt
+	selectMembershipsFromRoomStmt                   *sql.Stmt
+	selectLocalMembershipsFromRoomStmt              *sql.Stmt
+	selectRoomsWithMembershipStmt                   *sql.Stmt
+	updateMembershipStmt                            *sql.Stmt
+	selectKnownUsersStmt                            *sql.Stmt
+	updateMembershipForgetRoomStmt                  *sql.Stmt
+}
+
+func NewSqliteMembershipTable(db *sql.DB) (tables.Membership, error) {
+	s := &membershipStatements{
+		db: db,
+	}
+
+	return s, shared.StatementList{
+		{&s.insertMembershipStmt, insertMembershipSQL},
+		{&s.selectMembershipForUpdateStmt, selectMembershipForUpdateSQL},
+		{&s.selectMembershipFromRoomAndTargetStmt, selectMembershipFromRoomAndTargetSQL},
+		{&s.selectMembershipsFromRoomAndMembershipStmt, selectMembershipsFromRoomAndMembershipSQL},
+		{&s.selectLocalMembershipsFromRoomAndMembershipStmt, selectLocalMembershipsFromRoomAndMembershipSQL},
+		{&s.selectMembershipsFromRoomStmt, selectMembershipsFromRoomSQL},
+		{&s.selectLocalMembershipsFromRoomStmt, selectLocalMembershipsFromRoomSQL},
+		{&s.updateMembershipStmt, updateMembershipSQL},
+		{&s.selectRoomsWithMembershipStmt, selectRoomsWithMembershipSQL},
+		{&s.selectKnownUsersStmt, selectKnownUsersSQL},
+		{&s.updateMembershipForgetRoomStmt, updateMembershipForgetRoom},
+	}.Prepare(db)
+}
+
+func (s *membershipStatements) execSchema(db *sql.DB) error {
+	_, err := db.Exec(membershipSchema)
+	return err
+}
+
+func (s *membershipStatements) InsertMembership(
+	ctx context.Context, txn *sql.Tx,
+	roomNID types.RoomNID, targetUserNID types.EventStateKeyNID,
+	localTarget bool,
+) error {
+	stmt := sqlutil.TxStmt(txn, s.insertMembershipStmt)
+	_, err := stmt.ExecContext(ctx, roomNID, targetUserNID, localTarget)
+	return err
+}
+
+func (s *membershipStatements) SelectMembershipForUpdate(
+	ctx context.Context, txn *sql.Tx,
+	roomNID types.RoomNID, targetUserNID types.EventStateKeyNID,
+) (membership tables.MembershipState, err error) {
+	stmt := sqlutil.TxStmt(txn, s.selectMembershipForUpdateStmt)
+	err = stmt.QueryRowContext(
+		ctx, roomNID, targetUserNID,
+	).Scan(&membership)
+	return
+}
+
+func (s *membershipStatements) SelectMembershipFromRoomAndTarget(
+	ctx context.Context,
+	roomNID types.RoomNID, targetUserNID types.EventStateKeyNID,
+) (eventNID types.EventNID, membership tables.MembershipState, forgotten bool, err error) {
+	err = s.selectMembershipFromRoomAndTargetStmt.QueryRowContext(
+		ctx, roomNID, targetUserNID,
+	).Scan(&membership, &eventNID, &forgotten)
+	return
+}
+
+func (s *membershipStatements) SelectMembershipsFromRoom(
+	ctx context.Context,
+	roomNID types.RoomNID, localOnly bool,
+) (eventNIDs []types.EventNID, err error) {
+	var selectStmt *sql.Stmt
+	if localOnly {
+		selectStmt = s.selectLocalMembershipsFromRoomStmt
+	} else {
+		selectStmt = s.selectMembershipsFromRoomStmt
+	}
+	rows, err := selectStmt.QueryContext(ctx, roomNID)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "selectMembershipsFromRoom: rows.close() failed")
+
+	for rows.Next() {
+		var eNID types.EventNID
+		if err = rows.Scan(&eNID); err != nil {
+			return
+		}
+		eventNIDs = append(eventNIDs, eNID)
+	}
+	return
+}
+
+func (s *membershipStatements) SelectMembershipsFromRoomAndMembership(
+	ctx context.Context,
+	roomNID types.RoomNID, membership tables.MembershipState, localOnly bool,
+) (eventNIDs []types.EventNID, err error) {
+	var stmt *sql.Stmt
+	if localOnly {
+		stmt = s.selectLocalMembershipsFromRoomAndMembershipStmt
+	} else {
+		stmt = s.selectMembershipsFromRoomAndMembershipStmt
+	}
+	rows, err := stmt.QueryContext(ctx, roomNID, membership)
+	if err != nil {
+		return
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "selectMembershipsFromRoomAndMembership: rows.close() failed")
+
+	for rows.Next() {
+		var eNID types.EventNID
+		if err = rows.Scan(&eNID); err != nil {
+			return
+		}
+		eventNIDs = append(eventNIDs, eNID)
+	}
+	return
+}
+
+func (s *membershipStatements) UpdateMembership(
+	ctx context.Context, txn *sql.Tx,
+	roomNID types.RoomNID, targetUserNID types.EventStateKeyNID, senderUserNID types.EventStateKeyNID, membership tables.MembershipState,
+	eventNID types.EventNID, forgotten bool,
+) error {
+	stmt := sqlutil.TxStmt(txn, s.updateMembershipStmt)
+	_, err := stmt.ExecContext(
+		ctx, senderUserNID, membership, eventNID, forgotten, roomNID, targetUserNID,
+	)
+	return err
+}
+
+func (s *membershipStatements) SelectRoomsWithMembership(
+	ctx context.Context, userID types.EventStateKeyNID, membershipState tables.MembershipState,
+) ([]types.RoomNID, error) {
+	rows, err := s.selectRoomsWithMembershipStmt.QueryContext(ctx, membershipState, userID)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "SelectRoomsWithMembership: rows.close() failed")
+	var roomNIDs []types.RoomNID
+	for rows.Next() {
+		var roomNID types.RoomNID
+		if err := rows.Scan(&roomNID); err != nil {
+			return nil, err
+		}
+		roomNIDs = append(roomNIDs, roomNID)
+	}
+	return roomNIDs, nil
+}
+
+func (s *membershipStatements) SelectJoinedUsersSetForRooms(ctx context.Context, roomNIDs []types.RoomNID) (map[types.EventStateKeyNID]int, error) {
+	iRoomNIDs := make([]interface{}, len(roomNIDs))
+	for i, v := range roomNIDs {
+		iRoomNIDs[i] = v
+	}
+	query := strings.Replace(selectJoinedUsersSetForRoomsSQL, "($1)", sqlutil.QueryVariadic(len(iRoomNIDs)), 1)
+	rows, err := s.db.QueryContext(ctx, query, iRoomNIDs...)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "selectJoinedUsersSetForRooms: rows.close() failed")
+	result := make(map[types.EventStateKeyNID]int)
+	for rows.Next() {
+		var userID types.EventStateKeyNID
+		var count int
+		if err := rows.Scan(&userID, &count); err != nil {
+			return nil, err
+		}
+		result[userID] = count
+	}
+	return result, rows.Err()
+}
+
+func (s *membershipStatements) SelectKnownUsers(ctx context.Context, userID types.EventStateKeyNID, searchString string, limit int) ([]string, error) {
+	rows, err := s.selectKnownUsersStmt.QueryContext(ctx, userID, fmt.Sprintf("%%%s%%", searchString), limit)
+	if err != nil {
+		return nil, err
+	}
+	result := []string{}
+	defer internal.CloseAndLogIfError(ctx, rows, "SelectKnownUsers: rows.close() failed")
+	for rows.Next() {
+		var userID string
+		if err := rows.Scan(&userID); err != nil {
+			return nil, err
+		}
+		result = append(result, userID)
+	}
+	return result, rows.Err()
+}
+
+func (s *membershipStatements) UpdateForgetMembership(
+	ctx context.Context,
+	txn *sql.Tx, roomNID types.RoomNID, targetUserNID types.EventStateKeyNID,
+	forget bool,
+) error {
+	_, err := sqlutil.TxStmt(txn, s.updateMembershipForgetRoomStmt).ExecContext(
+		ctx, forget, roomNID, targetUserNID,
+	)
+	return err
+}

roomserver/storage/cosmosdb/previous_events_table.go

@@ -0,0 +1,131 @@
+// Copyright 2017-2018 New Vector Ltd
+// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+	"strings"
+
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/roomserver/storage/shared"
+	"github.com/matrix-org/dendrite/roomserver/storage/tables"
+	"github.com/matrix-org/dendrite/roomserver/types"
+)
+
+// TODO: previous_reference_sha256 was NOT NULL before but it broke sytest because
+// sytest sends no SHA256 sums in the prev_events references in the soft-fail tests.
+// In Postgres an empty BYTEA field is not NULL so it's fine there. In SQLite it
+// seems to care that it's empty and therefore hits a NOT NULL constraint on insert.
+// We should really work out what the right thing to do here is.
+const previousEventSchema = `
+  CREATE TABLE IF NOT EXISTS roomserver_previous_events (
+    previous_event_id TEXT NOT NULL,
+    previous_reference_sha256 BLOB,
+    event_nids TEXT NOT NULL,
+    UNIQUE (previous_event_id, previous_reference_sha256)
+  );
+`
+
+// Insert an entry into the previous_events table.
+// If there is already an entry indicating that an event references that previous event then
+// add the event NID to the list to indicate that this event references that previous event as well.
+// This should only be modified while holding a "FOR UPDATE" lock on the row in the rooms table for this room.
+// The lock is necessary to avoid data races when checking whether an event is already referenced by another event.
+const insertPreviousEventSQL = `
+	INSERT OR REPLACE INTO roomserver_previous_events
+	  (previous_event_id, previous_reference_sha256, event_nids)
+	  VALUES ($1, $2, $3)
+`
+
+const selectPreviousEventNIDsSQL = `
+	SELECT event_nids FROM roomserver_previous_events
+	  WHERE previous_event_id = $1 AND previous_reference_sha256 = $2
+`
+
+// Check if the event is referenced by another event in the table.
+// This should only be done while holding a "FOR UPDATE" lock on the row in the rooms table for this room.
+const selectPreviousEventExistsSQL = `
+	SELECT 1 FROM roomserver_previous_events
+	  WHERE previous_event_id = $1 AND previous_reference_sha256 = $2
+`
+
+type previousEventStatements struct {
+	db                            *sql.DB
+	insertPreviousEventStmt       *sql.Stmt
+	selectPreviousEventNIDsStmt   *sql.Stmt
+	selectPreviousEventExistsStmt *sql.Stmt
+}
+
+func NewSqlitePrevEventsTable(db *sql.DB) (tables.PreviousEvents, error) {
+	s := &previousEventStatements{
+		db: db,
+	}
+	_, err := db.Exec(previousEventSchema)
+	if err != nil {
+		return nil, err
+	}
+
+	return s, shared.StatementList{
+		{&s.insertPreviousEventStmt, insertPreviousEventSQL},
+		{&s.selectPreviousEventNIDsStmt, selectPreviousEventNIDsSQL},
+		{&s.selectPreviousEventExistsStmt, selectPreviousEventExistsSQL},
+	}.Prepare(db)
+}
+
+func (s *previousEventStatements) InsertPreviousEvent(
+	ctx context.Context,
+	txn *sql.Tx,
+	previousEventID string,
+	previousEventReferenceSHA256 []byte,
+	eventNID types.EventNID,
+) error {
+	var eventNIDs string
+	eventNIDAsString := fmt.Sprintf("%d", eventNID)
+	selectStmt := sqlutil.TxStmt(txn, s.selectPreviousEventExistsStmt)
+	err := selectStmt.QueryRowContext(ctx, previousEventID, previousEventReferenceSHA256).Scan(&eventNIDs)
+	if err != nil && err != sql.ErrNoRows {
+		return fmt.Errorf("selectStmt.QueryRowContext.Scan: %w", err)
+	}
+	var nids []string
+	if eventNIDs != "" {
+		nids = strings.Split(eventNIDs, ",")
+		for _, nid := range nids {
+			if nid == eventNIDAsString {
+				return nil
+			}
+		}
+		eventNIDs = strings.Join(append(nids, eventNIDAsString), ",")
+	} else {
+		eventNIDs = eventNIDAsString
+	}
+	insertStmt := sqlutil.TxStmt(txn, s.insertPreviousEventStmt)
+	_, err = insertStmt.ExecContext(
+		ctx, previousEventID, previousEventReferenceSHA256, eventNIDs,
+	)
+	return err
+}
+
+// Check if the event reference exists
+// Returns sql.ErrNoRows if the event reference doesn't exist.
+func (s *previousEventStatements) SelectPreviousEventExists(
+	ctx context.Context, txn *sql.Tx, eventID string, eventReferenceSHA256 []byte,
+) error {
+	var ok int64
+	stmt := sqlutil.TxStmt(txn, s.selectPreviousEventExistsStmt)
+	return stmt.QueryRowContext(ctx, eventID, eventReferenceSHA256).Scan(&ok)
+}

roomserver/storage/cosmosdb/published_table.go

@@ -0,0 +1,105 @@
+// Copyright 2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/roomserver/storage/shared"
+	"github.com/matrix-org/dendrite/roomserver/storage/tables"
+)
+
+const publishedSchema = `
+-- Stores which rooms are published in the room directory
+CREATE TABLE IF NOT EXISTS roomserver_published (
+    -- The room ID of the room
+    room_id TEXT NOT NULL PRIMARY KEY,
+    -- Whether it is published or not
+    published BOOLEAN NOT NULL DEFAULT false
+);
+`
+
+const upsertPublishedSQL = "" +
+	"INSERT OR REPLACE INTO roomserver_published (room_id, published) VALUES ($1, $2)"
+
+const selectAllPublishedSQL = "" +
+	"SELECT room_id FROM roomserver_published WHERE published = $1 ORDER BY room_id ASC"
+
+const selectPublishedSQL = "" +
+	"SELECT published FROM roomserver_published WHERE room_id = $1"
+
+type publishedStatements struct {
+	db                     *sql.DB
+	upsertPublishedStmt    *sql.Stmt
+	selectAllPublishedStmt *sql.Stmt
+	selectPublishedStmt    *sql.Stmt
+}
+
+func NewSqlitePublishedTable(db *sql.DB) (tables.Published, error) {
+	s := &publishedStatements{
+		db: db,
+	}
+	_, err := db.Exec(publishedSchema)
+	if err != nil {
+		return nil, err
+	}
+	return s, shared.StatementList{
+		{&s.upsertPublishedStmt, upsertPublishedSQL},
+		{&s.selectAllPublishedStmt, selectAllPublishedSQL},
+		{&s.selectPublishedStmt, selectPublishedSQL},
+	}.Prepare(db)
+}
+
+func (s *publishedStatements) UpsertRoomPublished(
+	ctx context.Context, txn *sql.Tx, roomID string, published bool,
+) error {
+	stmt := sqlutil.TxStmt(txn, s.upsertPublishedStmt)
+	_, err := stmt.ExecContext(ctx, roomID, published)
+	return err
+}
+
+func (s *publishedStatements) SelectPublishedFromRoomID(
+	ctx context.Context, roomID string,
+) (published bool, err error) {
+	err = s.selectPublishedStmt.QueryRowContext(ctx, roomID).Scan(&published)
+	if err == sql.ErrNoRows {
+		return false, nil
+	}
+	return
+}
+
+func (s *publishedStatements) SelectAllPublishedRooms(
+	ctx context.Context, published bool,
+) ([]string, error) {
+	rows, err := s.selectAllPublishedStmt.QueryContext(ctx, published)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "selectAllPublishedStmt: rows.close() failed")
+
+	var roomIDs []string
+	for rows.Next() {
+		var roomID string
+		if err = rows.Scan(&roomID); err != nil {
+			return nil, err
+		}
+
+		roomIDs = append(roomIDs, roomID)
+	}
+	return roomIDs, rows.Err()
+}

roomserver/storage/cosmosdb/redactions_table.go

@@ -0,0 +1,123 @@
+// Copyright 2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/roomserver/storage/shared"
+	"github.com/matrix-org/dendrite/roomserver/storage/tables"
+)
+
+const redactionsSchema = `
+-- Stores information about the redacted state of events.
+-- We need to track redactions rather than blindly updating the event JSON table on receipt of a redaction
+-- because we might receive the redaction BEFORE we receive the event which it redacts (think backfill).
+CREATE TABLE IF NOT EXISTS roomserver_redactions (
+    redaction_event_id TEXT PRIMARY KEY,
+	redacts_event_id TEXT NOT NULL,
+	-- Initially FALSE, set to TRUE when the redaction has been validated according to rooms v3+ spec
+	-- https://matrix.org/docs/spec/rooms/v3#authorization-rules-for-events
+	validated BOOLEAN NOT NULL
+);
+`
+
+const insertRedactionSQL = "" +
+	"INSERT OR IGNORE INTO roomserver_redactions (redaction_event_id, redacts_event_id, validated)" +
+	" VALUES ($1, $2, $3)"
+
+const selectRedactionInfoByRedactionEventIDSQL = "" +
+	"SELECT redaction_event_id, redacts_event_id, validated FROM roomserver_redactions" +
+	" WHERE redaction_event_id = $1"
+
+const selectRedactionInfoByEventBeingRedactedSQL = "" +
+	"SELECT redaction_event_id, redacts_event_id, validated FROM roomserver_redactions" +
+	" WHERE redacts_event_id = $1"
+
+const markRedactionValidatedSQL = "" +
+	" UPDATE roomserver_redactions SET validated = $2 WHERE redaction_event_id = $1"
+
+type redactionStatements struct {
+	db                                          *sql.DB
+	insertRedactionStmt                         *sql.Stmt
+	selectRedactionInfoByRedactionEventIDStmt   *sql.Stmt
+	selectRedactionInfoByEventBeingRedactedStmt *sql.Stmt
+	markRedactionValidatedStmt                  *sql.Stmt
+}
+
+func NewSqliteRedactionsTable(db *sql.DB) (tables.Redactions, error) {
+	s := &redactionStatements{
+		db: db,
+	}
+	_, err := db.Exec(redactionsSchema)
+	if err != nil {
+		return nil, err
+	}
+
+	return s, shared.StatementList{
+		{&s.insertRedactionStmt, insertRedactionSQL},
+		{&s.selectRedactionInfoByRedactionEventIDStmt, selectRedactionInfoByRedactionEventIDSQL},
+		{&s.selectRedactionInfoByEventBeingRedactedStmt, selectRedactionInfoByEventBeingRedactedSQL},
+		{&s.markRedactionValidatedStmt, markRedactionValidatedSQL},
+	}.Prepare(db)
+}
+
+func (s *redactionStatements) InsertRedaction(
+	ctx context.Context, txn *sql.Tx, info tables.RedactionInfo,
+) error {
+	stmt := sqlutil.TxStmt(txn, s.insertRedactionStmt)
+	_, err := stmt.ExecContext(ctx, info.RedactionEventID, info.RedactsEventID, info.Validated)
+	return err
+}
+
+func (s *redactionStatements) SelectRedactionInfoByRedactionEventID(
+	ctx context.Context, txn *sql.Tx, redactionEventID string,
+) (info *tables.RedactionInfo, err error) {
+	info = &tables.RedactionInfo{}
+	stmt := sqlutil.TxStmt(txn, s.selectRedactionInfoByRedactionEventIDStmt)
+	err = stmt.QueryRowContext(ctx, redactionEventID).Scan(
+		&info.RedactionEventID, &info.RedactsEventID, &info.Validated,
+	)
+	if err == sql.ErrNoRows {
+		info = nil
+		err = nil
+	}
+	return
+}
+
+func (s *redactionStatements) SelectRedactionInfoByEventBeingRedacted(
+	ctx context.Context, txn *sql.Tx, eventID string,
+) (info *tables.RedactionInfo, err error) {
+	info = &tables.RedactionInfo{}
+	stmt := sqlutil.TxStmt(txn, s.selectRedactionInfoByEventBeingRedactedStmt)
+	err = stmt.QueryRowContext(ctx, eventID).Scan(
+		&info.RedactionEventID, &info.RedactsEventID, &info.Validated,
+	)
+	if err == sql.ErrNoRows {
+		info = nil
+		err = nil
+	}
+	return
+}
+
+func (s *redactionStatements) MarkRedactionValidated(
+	ctx context.Context, txn *sql.Tx, redactionEventID string, validated bool,
+) error {
+	stmt := sqlutil.TxStmt(txn, s.markRedactionValidatedStmt)
+	_, err := stmt.ExecContext(ctx, redactionEventID, validated)
+	return err
+}

roomserver/storage/cosmosdb/room_aliases_table.go

@@ -0,0 +1,141 @@
+// Copyright 2017-2018 New Vector Ltd
+// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/roomserver/storage/shared"
+	"github.com/matrix-org/dendrite/roomserver/storage/tables"
+)
+
+const roomAliasesSchema = `
+  CREATE TABLE IF NOT EXISTS roomserver_room_aliases (
+    alias TEXT NOT NULL PRIMARY KEY,
+    room_id TEXT NOT NULL,
+    creator_id TEXT NOT NULL
+  );
+
+  CREATE INDEX IF NOT EXISTS roomserver_room_id_idx ON roomserver_room_aliases(room_id);
+`
+
+const insertRoomAliasSQL = `
+	INSERT INTO roomserver_room_aliases (alias, room_id, creator_id) VALUES ($1, $2, $3)
+`
+
+const selectRoomIDFromAliasSQL = `
+	SELECT room_id FROM roomserver_room_aliases WHERE alias = $1
+`
+
+const selectAliasesFromRoomIDSQL = `
+	SELECT alias FROM roomserver_room_aliases WHERE room_id = $1
+`
+
+const selectCreatorIDFromAliasSQL = `
+	SELECT creator_id FROM roomserver_room_aliases WHERE alias = $1
+`
+
+const deleteRoomAliasSQL = `
+	DELETE FROM roomserver_room_aliases WHERE alias = $1
+`
+
+type roomAliasesStatements struct {
+	db                           *sql.DB
+	insertRoomAliasStmt          *sql.Stmt
+	selectRoomIDFromAliasStmt    *sql.Stmt
+	selectAliasesFromRoomIDStmt  *sql.Stmt
+	selectCreatorIDFromAliasStmt *sql.Stmt
+	deleteRoomAliasStmt          *sql.Stmt
+}
+
+func NewSqliteRoomAliasesTable(db *sql.DB) (tables.RoomAliases, error) {
+	s := &roomAliasesStatements{
+		db: db,
+	}
+	_, err := db.Exec(roomAliasesSchema)
+	if err != nil {
+		return nil, err
+	}
+	return s, shared.StatementList{
+		{&s.insertRoomAliasStmt, insertRoomAliasSQL},
+		{&s.selectRoomIDFromAliasStmt, selectRoomIDFromAliasSQL},
+		{&s.selectAliasesFromRoomIDStmt, selectAliasesFromRoomIDSQL},
+		{&s.selectCreatorIDFromAliasStmt, selectCreatorIDFromAliasSQL},
+		{&s.deleteRoomAliasStmt, deleteRoomAliasSQL},
+	}.Prepare(db)
+}
+
+func (s *roomAliasesStatements) InsertRoomAlias(
+	ctx context.Context, txn *sql.Tx, alias string, roomID string, creatorUserID string,
+) error {
+	stmt := sqlutil.TxStmt(txn, s.insertRoomAliasStmt)
+	_, err := stmt.ExecContext(ctx, alias, roomID, creatorUserID)
+	return err
+}
+
+func (s *roomAliasesStatements) SelectRoomIDFromAlias(
+	ctx context.Context, alias string,
+) (roomID string, err error) {
+	err = s.selectRoomIDFromAliasStmt.QueryRowContext(ctx, alias).Scan(&roomID)
+	if err == sql.ErrNoRows {
+		return "", nil
+	}
+	return
+}
+
+func (s *roomAliasesStatements) SelectAliasesFromRoomID(
+	ctx context.Context, roomID string,
+) (aliases []string, err error) {
+	aliases = []string{}
+	rows, err := s.selectAliasesFromRoomIDStmt.QueryContext(ctx, roomID)
+	if err != nil {
+		return
+	}
+
+	defer internal.CloseAndLogIfError(ctx, rows, "selectAliasesFromRoomID: rows.close() failed")
+
+	for rows.Next() {
+		var alias string
+		if err = rows.Scan(&alias); err != nil {
+			return
+		}
+
+		aliases = append(aliases, alias)
+	}
+
+	return
+}
+
+func (s *roomAliasesStatements) SelectCreatorIDFromAlias(
+	ctx context.Context, alias string,
+) (creatorID string, err error) {
+	err = s.selectCreatorIDFromAliasStmt.QueryRowContext(ctx, alias).Scan(&creatorID)
+	if err == sql.ErrNoRows {
+		return "", nil
+	}
+	return
+}
+
+func (s *roomAliasesStatements) DeleteRoomAlias(
+	ctx context.Context, txn *sql.Tx, alias string,
+) error {
+	stmt := sqlutil.TxStmt(txn, s.deleteRoomAliasStmt)
+	_, err := stmt.ExecContext(ctx, alias)
+	return err
+}

roomserver/storage/cosmosdb/rooms_table.go

@@ -0,0 +1,296 @@
+// Copyright 2017-2018 New Vector Ltd
+// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+	"encoding/json"
+	"fmt"
+	"strings"
+
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/roomserver/storage/shared"
+	"github.com/matrix-org/dendrite/roomserver/storage/tables"
+	"github.com/matrix-org/dendrite/roomserver/types"
+	"github.com/matrix-org/gomatrixserverlib"
+)
+
+const roomsSchema = `
+  CREATE TABLE IF NOT EXISTS roomserver_rooms (
+    room_nid INTEGER PRIMARY KEY AUTOINCREMENT,
+    room_id TEXT NOT NULL UNIQUE,
+    latest_event_nids TEXT NOT NULL DEFAULT '[]',
+    last_event_sent_nid INTEGER NOT NULL DEFAULT 0,
+    state_snapshot_nid INTEGER NOT NULL DEFAULT 0,
+    room_version TEXT NOT NULL
+  );
+`
+
+// Same as insertEventTypeNIDSQL
+const insertRoomNIDSQL = `
+	INSERT INTO roomserver_rooms (room_id, room_version) VALUES ($1, $2)
+	  ON CONFLICT DO NOTHING;
+`
+
+const selectRoomNIDSQL = "" +
+	"SELECT room_nid FROM roomserver_rooms WHERE room_id = $1"
+
+const selectLatestEventNIDsSQL = "" +
+	"SELECT latest_event_nids, state_snapshot_nid FROM roomserver_rooms WHERE room_nid = $1"
+
+const selectLatestEventNIDsForUpdateSQL = "" +
+	"SELECT latest_event_nids, last_event_sent_nid, state_snapshot_nid FROM roomserver_rooms WHERE room_nid = $1"
+
+const updateLatestEventNIDsSQL = "" +
+	"UPDATE roomserver_rooms SET latest_event_nids = $1, last_event_sent_nid = $2, state_snapshot_nid = $3 WHERE room_nid = $4"
+
+const selectRoomVersionsForRoomNIDsSQL = "" +
+	"SELECT room_nid, room_version FROM roomserver_rooms WHERE room_nid IN ($1)"
+
+const selectRoomInfoSQL = "" +
+	"SELECT room_version, room_nid, state_snapshot_nid, latest_event_nids FROM roomserver_rooms WHERE room_id = $1"
+
+const selectRoomIDsSQL = "" +
+	"SELECT room_id FROM roomserver_rooms"
+
+const bulkSelectRoomIDsSQL = "" +
+	"SELECT room_id FROM roomserver_rooms WHERE room_nid IN ($1)"
+
+const bulkSelectRoomNIDsSQL = "" +
+	"SELECT room_nid FROM roomserver_rooms WHERE room_id IN ($1)"
+
+type roomStatements struct {
+	db                                 *sql.DB
+	insertRoomNIDStmt                  *sql.Stmt
+	selectRoomNIDStmt                  *sql.Stmt
+	selectLatestEventNIDsStmt          *sql.Stmt
+	selectLatestEventNIDsForUpdateStmt *sql.Stmt
+	updateLatestEventNIDsStmt          *sql.Stmt
+	//selectRoomVersionForRoomNIDStmt    *sql.Stmt
+	selectRoomInfoStmt *sql.Stmt
+	selectRoomIDsStmt  *sql.Stmt
+}
+
+func NewSqliteRoomsTable(db *sql.DB) (tables.Rooms, error) {
+	s := &roomStatements{
+		db: db,
+	}
+	_, err := db.Exec(roomsSchema)
+	if err != nil {
+		return nil, err
+	}
+	return s, shared.StatementList{
+		{&s.insertRoomNIDStmt, insertRoomNIDSQL},
+		{&s.selectRoomNIDStmt, selectRoomNIDSQL},
+		{&s.selectLatestEventNIDsStmt, selectLatestEventNIDsSQL},
+		{&s.selectLatestEventNIDsForUpdateStmt, selectLatestEventNIDsForUpdateSQL},
+		{&s.updateLatestEventNIDsStmt, updateLatestEventNIDsSQL},
+		//{&s.selectRoomVersionForRoomNIDsStmt, selectRoomVersionForRoomNIDsSQL},
+		{&s.selectRoomInfoStmt, selectRoomInfoSQL},
+		{&s.selectRoomIDsStmt, selectRoomIDsSQL},
+	}.Prepare(db)
+}
+
+func (s *roomStatements) SelectRoomIDs(ctx context.Context) ([]string, error) {
+	rows, err := s.selectRoomIDsStmt.QueryContext(ctx)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "selectRoomIDsStmt: rows.close() failed")
+	var roomIDs []string
+	for rows.Next() {
+		var roomID string
+		if err = rows.Scan(&roomID); err != nil {
+			return nil, err
+		}
+		roomIDs = append(roomIDs, roomID)
+	}
+	return roomIDs, nil
+}
+
+func (s *roomStatements) SelectRoomInfo(ctx context.Context, roomID string) (*types.RoomInfo, error) {
+	var info types.RoomInfo
+	var latestNIDsJSON string
+	err := s.selectRoomInfoStmt.QueryRowContext(ctx, roomID).Scan(
+		&info.RoomVersion, &info.RoomNID, &info.StateSnapshotNID, &latestNIDsJSON,
+	)
+	if err != nil {
+		if err == sql.ErrNoRows {
+			return nil, nil
+		}
+		return nil, err
+	}
+	var latestNIDs []int64
+	if err = json.Unmarshal([]byte(latestNIDsJSON), &latestNIDs); err != nil {
+		return nil, err
+	}
+	info.IsStub = len(latestNIDs) == 0
+	return &info, err
+}
+
+func (s *roomStatements) InsertRoomNID(
+	ctx context.Context, txn *sql.Tx,
+	roomID string, roomVersion gomatrixserverlib.RoomVersion,
+) (roomNID types.RoomNID, err error) {
+	insertStmt := sqlutil.TxStmt(txn, s.insertRoomNIDStmt)
+	_, err = insertStmt.ExecContext(ctx, roomID, roomVersion)
+	if err != nil {
+		return 0, fmt.Errorf("insertStmt.ExecContext: %w", err)
+	}
+	roomNID, err = s.SelectRoomNID(ctx, txn, roomID)
+	if err != nil {
+		return 0, fmt.Errorf("s.SelectRoomNID: %w", err)
+	}
+	return
+}
+
+func (s *roomStatements) SelectRoomNID(
+	ctx context.Context, txn *sql.Tx, roomID string,
+) (types.RoomNID, error) {
+	var roomNID int64
+	stmt := sqlutil.TxStmt(txn, s.selectRoomNIDStmt)
+	err := stmt.QueryRowContext(ctx, roomID).Scan(&roomNID)
+	return types.RoomNID(roomNID), err
+}
+
+func (s *roomStatements) SelectLatestEventNIDs(
+	ctx context.Context, txn *sql.Tx, roomNID types.RoomNID,
+) ([]types.EventNID, types.StateSnapshotNID, error) {
+	var eventNIDs []types.EventNID
+	var nidsJSON string
+	var stateSnapshotNID int64
+	stmt := sqlutil.TxStmt(txn, s.selectLatestEventNIDsStmt)
+	err := stmt.QueryRowContext(ctx, int64(roomNID)).Scan(&nidsJSON, &stateSnapshotNID)
+	if err != nil {
+		return nil, 0, err
+	}
+	if err := json.Unmarshal([]byte(nidsJSON), &eventNIDs); err != nil {
+		return nil, 0, err
+	}
+	return eventNIDs, types.StateSnapshotNID(stateSnapshotNID), nil
+}
+
+func (s *roomStatements) SelectLatestEventsNIDsForUpdate(
+	ctx context.Context, txn *sql.Tx, roomNID types.RoomNID,
+) ([]types.EventNID, types.EventNID, types.StateSnapshotNID, error) {
+	var eventNIDs []types.EventNID
+	var nidsJSON string
+	var lastEventSentNID int64
+	var stateSnapshotNID int64
+	stmt := sqlutil.TxStmt(txn, s.selectLatestEventNIDsForUpdateStmt)
+	err := stmt.QueryRowContext(ctx, int64(roomNID)).Scan(&nidsJSON, &lastEventSentNID, &stateSnapshotNID)
+	if err != nil {
+		return nil, 0, 0, err
+	}
+	if err := json.Unmarshal([]byte(nidsJSON), &eventNIDs); err != nil {
+		return nil, 0, 0, err
+	}
+	return eventNIDs, types.EventNID(lastEventSentNID), types.StateSnapshotNID(stateSnapshotNID), nil
+}
+
+func (s *roomStatements) UpdateLatestEventNIDs(
+	ctx context.Context,
+	txn *sql.Tx,
+	roomNID types.RoomNID,
+	eventNIDs []types.EventNID,
+	lastEventSentNID types.EventNID,
+	stateSnapshotNID types.StateSnapshotNID,
+) error {
+	stmt := sqlutil.TxStmt(txn, s.updateLatestEventNIDsStmt)
+	_, err := stmt.ExecContext(
+		ctx,
+		eventNIDsAsArray(eventNIDs),
+		int64(lastEventSentNID),
+		int64(stateSnapshotNID),
+		roomNID,
+	)
+	return err
+}
+
+func (s *roomStatements) SelectRoomVersionsForRoomNIDs(
+	ctx context.Context, roomNIDs []types.RoomNID,
+) (map[types.RoomNID]gomatrixserverlib.RoomVersion, error) {
+	sqlStr := strings.Replace(selectRoomVersionsForRoomNIDsSQL, "($1)", sqlutil.QueryVariadic(len(roomNIDs)), 1)
+	sqlPrep, err := s.db.Prepare(sqlStr)
+	if err != nil {
+		return nil, err
+	}
+	iRoomNIDs := make([]interface{}, len(roomNIDs))
+	for i, v := range roomNIDs {
+		iRoomNIDs[i] = v
+	}
+	rows, err := sqlPrep.QueryContext(ctx, iRoomNIDs...)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "selectRoomVersionsForRoomNIDsStmt: rows.close() failed")
+	result := make(map[types.RoomNID]gomatrixserverlib.RoomVersion)
+	for rows.Next() {
+		var roomNID types.RoomNID
+		var roomVersion gomatrixserverlib.RoomVersion
+		if err = rows.Scan(&roomNID, &roomVersion); err != nil {
+			return nil, err
+		}
+		result[roomNID] = roomVersion
+	}
+	return result, nil
+}
+
+func (s *roomStatements) BulkSelectRoomIDs(ctx context.Context, roomNIDs []types.RoomNID) ([]string, error) {
+	iRoomNIDs := make([]interface{}, len(roomNIDs))
+	for i, v := range roomNIDs {
+		iRoomNIDs[i] = v
+	}
+	sqlQuery := strings.Replace(bulkSelectRoomIDsSQL, "($1)", sqlutil.QueryVariadic(len(roomNIDs)), 1)
+	rows, err := s.db.QueryContext(ctx, sqlQuery, iRoomNIDs...)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "bulkSelectRoomIDsStmt: rows.close() failed")
+	var roomIDs []string
+	for rows.Next() {
+		var roomID string
+		if err = rows.Scan(&roomID); err != nil {
+			return nil, err
+		}
+		roomIDs = append(roomIDs, roomID)
+	}
+	return roomIDs, nil
+}
+
+func (s *roomStatements) BulkSelectRoomNIDs(ctx context.Context, roomIDs []string) ([]types.RoomNID, error) {
+	iRoomIDs := make([]interface{}, len(roomIDs))
+	for i, v := range roomIDs {
+		iRoomIDs[i] = v
+	}
+	sqlQuery := strings.Replace(bulkSelectRoomNIDsSQL, "($1)", sqlutil.QueryVariadic(len(roomIDs)), 1)
+	rows, err := s.db.QueryContext(ctx, sqlQuery, iRoomIDs...)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "bulkSelectRoomNIDsStmt: rows.close() failed")
+	var roomNIDs []types.RoomNID
+	for rows.Next() {
+		var roomNID types.RoomNID
+		if err = rows.Scan(&roomNID); err != nil {
+			return nil, err
+		}
+		roomNIDs = append(roomNIDs, roomNID)
+	}
+	return roomNIDs, nil
+}

roomserver/storage/cosmosdb/state_block_table.go

@@ -0,0 +1,289 @@
+// Copyright 2017-2018 New Vector Ltd
+// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+	"sort"
+	"strings"
+
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/roomserver/storage/shared"
+	"github.com/matrix-org/dendrite/roomserver/storage/tables"
+	"github.com/matrix-org/dendrite/roomserver/types"
+	"github.com/matrix-org/util"
+)
+
+const stateDataSchema = `
+  CREATE TABLE IF NOT EXISTS roomserver_state_block (
+    state_block_nid INTEGER NOT NULL,
+    event_type_nid INTEGER NOT NULL,
+    event_state_key_nid INTEGER NOT NULL,
+    event_nid INTEGER NOT NULL,
+    UNIQUE (state_block_nid, event_type_nid, event_state_key_nid)
+  );
+`
+
+const insertStateDataSQL = "" +
+	"INSERT INTO roomserver_state_block (state_block_nid, event_type_nid, event_state_key_nid, event_nid)" +
+	" VALUES ($1, $2, $3, $4)"
+
+const selectNextStateBlockNIDSQL = `
+SELECT IFNULL(MAX(state_block_nid), 0) + 1 FROM roomserver_state_block
+`
+
+// Bulk state lookup by numeric state block ID.
+// Sort by the state_block_nid, event_type_nid, event_state_key_nid
+// This means that all the entries for a given state_block_nid will appear
+// together in the list and those entries will sorted by event_type_nid
+// and event_state_key_nid. This property makes it easier to merge two
+// state data blocks together.
+const bulkSelectStateBlockEntriesSQL = "" +
+	"SELECT state_block_nid, event_type_nid, event_state_key_nid, event_nid" +
+	" FROM roomserver_state_block WHERE state_block_nid IN ($1)" +
+	" ORDER BY state_block_nid, event_type_nid, event_state_key_nid"
+
+// Bulk state lookup by numeric state block ID.
+// Filters the rows in each block to the requested types and state keys.
+// We would like to restrict to particular type state key pairs but we are
+// restricted by the query language to pull the cross product of a list
+// of types and a list state_keys. So we have to filter the result in the
+// application to restrict it to the list of event types and state keys we
+// actually wanted.
+const bulkSelectFilteredStateBlockEntriesSQL = "" +
+	"SELECT state_block_nid, event_type_nid, event_state_key_nid, event_nid" +
+	" FROM roomserver_state_block WHERE state_block_nid IN ($1)" +
+	" AND event_type_nid IN ($2) AND event_state_key_nid IN ($3)" +
+	" ORDER BY state_block_nid, event_type_nid, event_state_key_nid"
+
+type stateBlockStatements struct {
+	db                                      *sql.DB
+	insertStateDataStmt                     *sql.Stmt
+	selectNextStateBlockNIDStmt             *sql.Stmt
+	bulkSelectStateBlockEntriesStmt         *sql.Stmt
+	bulkSelectFilteredStateBlockEntriesStmt *sql.Stmt
+}
+
+func NewSqliteStateBlockTable(db *sql.DB) (tables.StateBlock, error) {
+	s := &stateBlockStatements{
+		db: db,
+	}
+	_, err := db.Exec(stateDataSchema)
+	if err != nil {
+		return nil, err
+	}
+
+	return s, shared.StatementList{
+		{&s.insertStateDataStmt, insertStateDataSQL},
+		{&s.selectNextStateBlockNIDStmt, selectNextStateBlockNIDSQL},
+		{&s.bulkSelectStateBlockEntriesStmt, bulkSelectStateBlockEntriesSQL},
+		{&s.bulkSelectFilteredStateBlockEntriesStmt, bulkSelectFilteredStateBlockEntriesSQL},
+	}.Prepare(db)
+}
+
+func (s *stateBlockStatements) BulkInsertStateData(
+	ctx context.Context, txn *sql.Tx,
+	entries []types.StateEntry,
+) (types.StateBlockNID, error) {
+	if len(entries) == 0 {
+		return 0, nil
+	}
+	var stateBlockNID types.StateBlockNID
+	err := sqlutil.TxStmt(txn, s.selectNextStateBlockNIDStmt).QueryRowContext(ctx).Scan(&stateBlockNID)
+	if err != nil {
+		return 0, err
+	}
+	for _, entry := range entries {
+		_, err = sqlutil.TxStmt(txn, s.insertStateDataStmt).ExecContext(
+			ctx,
+			int64(stateBlockNID),
+			int64(entry.EventTypeNID),
+			int64(entry.EventStateKeyNID),
+			int64(entry.EventNID),
+		)
+		if err != nil {
+			return 0, err
+		}
+	}
+	return stateBlockNID, err
+}
+
+func (s *stateBlockStatements) BulkSelectStateBlockEntries(
+	ctx context.Context, stateBlockNIDs []types.StateBlockNID,
+) ([]types.StateEntryList, error) {
+	nids := make([]interface{}, len(stateBlockNIDs))
+	for k, v := range stateBlockNIDs {
+		nids[k] = v
+	}
+	selectOrig := strings.Replace(bulkSelectStateBlockEntriesSQL, "($1)", sqlutil.QueryVariadic(len(nids)), 1)
+	selectStmt, err := s.db.Prepare(selectOrig)
+	if err != nil {
+		return nil, err
+	}
+	rows, err := selectStmt.QueryContext(ctx, nids...)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "bulkSelectStateBlockEntries: rows.close() failed")
+
+	results := make([]types.StateEntryList, len(stateBlockNIDs))
+	// current is a pointer to the StateEntryList to append the state entries to.
+	var current *types.StateEntryList
+	i := 0
+	for rows.Next() {
+		var (
+			stateBlockNID    int64
+			eventTypeNID     int64
+			eventStateKeyNID int64
+			eventNID         int64
+			entry            types.StateEntry
+		)
+		if err := rows.Scan(
+			&stateBlockNID, &eventTypeNID, &eventStateKeyNID, &eventNID,
+		); err != nil {
+			return nil, err
+		}
+		entry.EventTypeNID = types.EventTypeNID(eventTypeNID)
+		entry.EventStateKeyNID = types.EventStateKeyNID(eventStateKeyNID)
+		entry.EventNID = types.EventNID(eventNID)
+		if current == nil || types.StateBlockNID(stateBlockNID) != current.StateBlockNID {
+			// The state entry row is for a different state data block to the current one.
+			// So we start appending to the next entry in the list.
+			current = &results[i]
+			current.StateBlockNID = types.StateBlockNID(stateBlockNID)
+			i++
+		}
+		current.StateEntries = append(current.StateEntries, entry)
+	}
+	if i != len(nids) {
+		return nil, fmt.Errorf("storage: state data NIDs missing from the database (%d != %d)", i, len(nids))
+	}
+	return results, nil
+}
+
+func (s *stateBlockStatements) BulkSelectFilteredStateBlockEntries(
+	ctx context.Context,
+	stateBlockNIDs []types.StateBlockNID,
+	stateKeyTuples []types.StateKeyTuple,
+) ([]types.StateEntryList, error) {
+	tuples := stateKeyTupleSorter(stateKeyTuples)
+	// Sort the tuples so that we can run binary search against them as we filter the rows returned by the db.
+	sort.Sort(tuples)
+
+	eventTypeNIDArray, eventStateKeyNIDArray := tuples.typesAndStateKeysAsArrays()
+	sqlStatement := strings.Replace(bulkSelectFilteredStateBlockEntriesSQL, "($1)", sqlutil.QueryVariadic(len(stateBlockNIDs)), 1)
+	sqlStatement = strings.Replace(sqlStatement, "($2)", sqlutil.QueryVariadicOffset(len(eventTypeNIDArray), len(stateBlockNIDs)), 1)
+	sqlStatement = strings.Replace(sqlStatement, "($3)", sqlutil.QueryVariadicOffset(len(eventStateKeyNIDArray), len(stateBlockNIDs)+len(eventTypeNIDArray)), 1)
+
+	var params []interface{}
+	for _, val := range stateBlockNIDs {
+		params = append(params, int64(val))
+	}
+	for _, val := range eventTypeNIDArray {
+		params = append(params, val)
+	}
+	for _, val := range eventStateKeyNIDArray {
+		params = append(params, val)
+	}
+
+	rows, err := s.db.QueryContext(
+		ctx,
+		sqlStatement,
+		params...,
+	)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "bulkSelectFilteredStateBlockEntries: rows.close() failed")
+
+	var results []types.StateEntryList
+	var current types.StateEntryList
+	for rows.Next() {
+		var (
+			stateBlockNID    int64
+			eventTypeNID     int64
+			eventStateKeyNID int64
+			eventNID         int64
+			entry            types.StateEntry
+		)
+		if err := rows.Scan(
+			&stateBlockNID, &eventTypeNID, &eventStateKeyNID, &eventNID,
+		); err != nil {
+			return nil, err
+		}
+		entry.EventTypeNID = types.EventTypeNID(eventTypeNID)
+		entry.EventStateKeyNID = types.EventStateKeyNID(eventStateKeyNID)
+		entry.EventNID = types.EventNID(eventNID)
+
+		// We can use binary search here because we sorted the tuples earlier
+		if !tuples.contains(entry.StateKeyTuple) {
+			// The select will return the cross product of types and state keys.
+			// So we need to check if type of the entry is in the list.
+			continue
+		}
+
+		if types.StateBlockNID(stateBlockNID) != current.StateBlockNID {
+			// The state entry row is for a different state data block to the current one.
+			// So we append the current entry to the results and start adding to a new one.
+			// The first time through the loop current will be empty.
+			if current.StateEntries != nil {
+				results = append(results, current)
+			}
+			current = types.StateEntryList{StateBlockNID: types.StateBlockNID(stateBlockNID)}
+		}
+		current.StateEntries = append(current.StateEntries, entry)
+	}
+	// Add the last entry to the list if it is not empty.
+	if current.StateEntries != nil {
+		results = append(results, current)
+	}
+	return results, nil
+}
+
+type stateKeyTupleSorter []types.StateKeyTuple
+
+func (s stateKeyTupleSorter) Len() int           { return len(s) }
+func (s stateKeyTupleSorter) Less(i, j int) bool { return s[i].LessThan(s[j]) }
+func (s stateKeyTupleSorter) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
+
+// Check whether a tuple is in the list. Assumes that the list is sorted.
+func (s stateKeyTupleSorter) contains(value types.StateKeyTuple) bool {
+	i := sort.Search(len(s), func(i int) bool { return !s[i].LessThan(value) })
+	return i < len(s) && s[i] == value
+}
+
+// List the unique eventTypeNIDs and eventStateKeyNIDs.
+// Assumes that the list is sorted.
+func (s stateKeyTupleSorter) typesAndStateKeysAsArrays() (eventTypeNIDs []int64, eventStateKeyNIDs []int64) {
+	eventTypeNIDs = make([]int64, len(s))
+	eventStateKeyNIDs = make([]int64, len(s))
+	for i := range s {
+		eventTypeNIDs[i] = int64(s[i].EventTypeNID)
+		eventStateKeyNIDs[i] = int64(s[i].EventStateKeyNID)
+	}
+	eventTypeNIDs = eventTypeNIDs[:util.SortAndUnique(int64Sorter(eventTypeNIDs))]
+	eventStateKeyNIDs = eventStateKeyNIDs[:util.SortAndUnique(int64Sorter(eventStateKeyNIDs))]
+	return
+}
+
+type int64Sorter []int64
+
+func (s int64Sorter) Len() int           { return len(s) }
+func (s int64Sorter) Less(i, j int) bool { return s[i] < s[j] }
+func (s int64Sorter) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }

roomserver/storage/cosmosdb/state_block_table_test.go

@@ -0,0 +1,86 @@
+// Copyright 2017-2018 New Vector Ltd
+// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"sort"
+	"testing"
+
+	"github.com/matrix-org/dendrite/roomserver/types"
+)
+
+func TestStateKeyTupleSorter(t *testing.T) {
+	input := stateKeyTupleSorter{
+		{EventTypeNID: 1, EventStateKeyNID: 2},
+		{EventTypeNID: 1, EventStateKeyNID: 4},
+		{EventTypeNID: 2, EventStateKeyNID: 2},
+		{EventTypeNID: 1, EventStateKeyNID: 1},
+	}
+	want := []types.StateKeyTuple{
+		{EventTypeNID: 1, EventStateKeyNID: 1},
+		{EventTypeNID: 1, EventStateKeyNID: 2},
+		{EventTypeNID: 1, EventStateKeyNID: 4},
+		{EventTypeNID: 2, EventStateKeyNID: 2},
+	}
+	doNotWant := []types.StateKeyTuple{
+		{EventTypeNID: 0, EventStateKeyNID: 0},
+		{EventTypeNID: 1, EventStateKeyNID: 3},
+		{EventTypeNID: 2, EventStateKeyNID: 1},
+		{EventTypeNID: 3, EventStateKeyNID: 1},
+	}
+	wantTypeNIDs := []int64{1, 2}
+	wantStateKeyNIDs := []int64{1, 2, 4}
+
+	// Sort the input and check it's in the right order.
+	sort.Sort(input)
+	gotTypeNIDs, gotStateKeyNIDs := input.typesAndStateKeysAsArrays()
+
+	for i := range want {
+		if input[i] != want[i] {
+			t.Errorf("Wanted %#v at index %d got %#v", want[i], i, input[i])
+		}
+
+		if !input.contains(want[i]) {
+			t.Errorf("Wanted %#v.contains(%#v) to be true but got false", input, want[i])
+		}
+	}
+
+	for i := range doNotWant {
+		if input.contains(doNotWant[i]) {
+			t.Errorf("Wanted %#v.contains(%#v) to be false but got true", input, doNotWant[i])
+		}
+	}
+
+	if len(wantTypeNIDs) != len(gotTypeNIDs) {
+		t.Fatalf("Wanted type NIDs %#v got %#v", wantTypeNIDs, gotTypeNIDs)
+	}
+
+	for i := range wantTypeNIDs {
+		if wantTypeNIDs[i] != gotTypeNIDs[i] {
+			t.Fatalf("Wanted type NIDs %#v got %#v", wantTypeNIDs, gotTypeNIDs)
+		}
+	}
+
+	if len(wantStateKeyNIDs) != len(gotStateKeyNIDs) {
+		t.Fatalf("Wanted state key NIDs %#v got %#v", wantStateKeyNIDs, gotStateKeyNIDs)
+	}
+
+	for i := range wantStateKeyNIDs {
+		if wantStateKeyNIDs[i] != gotStateKeyNIDs[i] {
+			t.Fatalf("Wanted type NIDs %#v got %#v", wantTypeNIDs, gotTypeNIDs)
+		}
+	}
+}

roomserver/storage/cosmosdb/state_snapshot_table.go

@@ -0,0 +1,126 @@
+// Copyright 2017-2018 New Vector Ltd
+// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+	"encoding/json"
+	"fmt"
+	"strings"
+
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/roomserver/storage/shared"
+	"github.com/matrix-org/dendrite/roomserver/storage/tables"
+	"github.com/matrix-org/dendrite/roomserver/types"
+)
+
+const stateSnapshotSchema = `
+  CREATE TABLE IF NOT EXISTS roomserver_state_snapshots (
+    state_snapshot_nid INTEGER PRIMARY KEY AUTOINCREMENT,
+    room_nid INTEGER NOT NULL,
+    state_block_nids TEXT NOT NULL DEFAULT '[]'
+  );
+`
+
+const insertStateSQL = `
+	INSERT INTO roomserver_state_snapshots (room_nid, state_block_nids)
+	  VALUES ($1, $2);`
+
+// Bulk state data NID lookup.
+// Sorting by state_snapshot_nid means we can use binary search over the result
+// to lookup the state data NIDs for a state snapshot NID.
+const bulkSelectStateBlockNIDsSQL = "" +
+	"SELECT state_snapshot_nid, state_block_nids FROM roomserver_state_snapshots" +
+	" WHERE state_snapshot_nid IN ($1) ORDER BY state_snapshot_nid ASC"
+
+type stateSnapshotStatements struct {
+	db                           *sql.DB
+	insertStateStmt              *sql.Stmt
+	bulkSelectStateBlockNIDsStmt *sql.Stmt
+}
+
+func NewSqliteStateSnapshotTable(db *sql.DB) (tables.StateSnapshot, error) {
+	s := &stateSnapshotStatements{
+		db: db,
+	}
+	_, err := db.Exec(stateSnapshotSchema)
+	if err != nil {
+		return nil, err
+	}
+
+	return s, shared.StatementList{
+		{&s.insertStateStmt, insertStateSQL},
+		{&s.bulkSelectStateBlockNIDsStmt, bulkSelectStateBlockNIDsSQL},
+	}.Prepare(db)
+}
+
+func (s *stateSnapshotStatements) InsertState(
+	ctx context.Context, txn *sql.Tx, roomNID types.RoomNID, stateBlockNIDs []types.StateBlockNID,
+) (stateNID types.StateSnapshotNID, err error) {
+	stateBlockNIDsJSON, err := json.Marshal(stateBlockNIDs)
+	if err != nil {
+		return
+	}
+	insertStmt := sqlutil.TxStmt(txn, s.insertStateStmt)
+	res, err := insertStmt.ExecContext(ctx, int64(roomNID), string(stateBlockNIDsJSON))
+	if err != nil {
+		return 0, err
+	}
+	lastRowID, err := res.LastInsertId()
+	if err != nil {
+		return 0, err
+	}
+	stateNID = types.StateSnapshotNID(lastRowID)
+	return
+}
+
+func (s *stateSnapshotStatements) BulkSelectStateBlockNIDs(
+	ctx context.Context, stateNIDs []types.StateSnapshotNID,
+) ([]types.StateBlockNIDList, error) {
+	nids := make([]interface{}, len(stateNIDs))
+	for k, v := range stateNIDs {
+		nids[k] = v
+	}
+	selectOrig := strings.Replace(bulkSelectStateBlockNIDsSQL, "($1)", sqlutil.QueryVariadic(len(nids)), 1)
+	selectStmt, err := s.db.Prepare(selectOrig)
+	if err != nil {
+		return nil, err
+	}
+
+	rows, err := selectStmt.QueryContext(ctx, nids...)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "bulkSelectStateBlockNIDs: rows.close() failed")
+	results := make([]types.StateBlockNIDList, len(stateNIDs))
+	i := 0
+	for ; rows.Next(); i++ {
+		result := &results[i]
+		var stateBlockNIDsJSON string
+		if err := rows.Scan(&result.StateSnapshotNID, &stateBlockNIDsJSON); err != nil {
+			return nil, err
+		}
+		if err := json.Unmarshal([]byte(stateBlockNIDsJSON), &result.StateBlockNIDs); err != nil {
+			return nil, err
+		}
+	}
+	if i != len(stateNIDs) {
+		return nil, fmt.Errorf("storage: state NIDs missing from the database (%d != %d)", i, len(stateNIDs))
+	}
+	return results, nil
+}

roomserver/storage/cosmosdb/storage.go

@@ -0,0 +1,187 @@
+// Copyright 2017-2018 New Vector Ltd
+// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+
+	_ "github.com/mattn/go-sqlite3"
+
+	"github.com/matrix-org/dendrite/internal/caching"
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/roomserver/storage/shared"
+	"github.com/matrix-org/dendrite/roomserver/storage/sqlite3/deltas"
+	"github.com/matrix-org/dendrite/roomserver/types"
+	"github.com/matrix-org/dendrite/setup/config"
+	"github.com/matrix-org/gomatrixserverlib"
+)
+
+// A Database is used to store room events and stream offsets.
+type Database struct {
+	shared.Database
+}
+
+// Open a sqlite database.
+func Open(dbProperties *config.DatabaseOptions, cache caching.RoomServerCaches) (*Database, error) {
+	var d Database
+	var db *sql.DB
+	var err error
+	if db, err = sqlutil.Open(dbProperties); err != nil {
+		return nil, err
+	}
+
+	//db.Exec("PRAGMA journal_mode=WAL;")
+	//db.Exec("PRAGMA read_uncommitted = true;")
+
+	// FIXME: We are leaking connections somewhere. Setting this to 2 will eventually
+	// cause the roomserver to be unresponsive to new events because something will
+	// acquire the global mutex and never unlock it because it is waiting for a connection
+	// which it will never obtain.
+	db.SetMaxOpenConns(20)
+
+	// Create tables before executing migrations so we don't fail if the table is missing,
+	// and THEN prepare statements so we don't fail due to referencing new columns
+	ms := membershipStatements{}
+	if err := ms.execSchema(db); err != nil {
+		return nil, err
+	}
+	m := sqlutil.NewMigrations()
+	deltas.LoadAddForgottenColumn(m)
+	if err := m.RunDeltas(db, dbProperties); err != nil {
+		return nil, err
+	}
+	if err := d.prepare(db, cache); err != nil {
+		return nil, err
+	}
+
+	return &d, nil
+}
+
+// nolint: gocyclo
+func (d *Database) prepare(db *sql.DB, cache caching.RoomServerCaches) error {
+	var err error
+	eventStateKeys, err := NewSqliteEventStateKeysTable(db)
+	if err != nil {
+		return err
+	}
+	eventTypes, err := NewSqliteEventTypesTable(db)
+	if err != nil {
+		return err
+	}
+	eventJSON, err := NewSqliteEventJSONTable(db)
+	if err != nil {
+		return err
+	}
+	events, err := NewSqliteEventsTable(db)
+	if err != nil {
+		return err
+	}
+	rooms, err := NewSqliteRoomsTable(db)
+	if err != nil {
+		return err
+	}
+	transactions, err := NewSqliteTransactionsTable(db)
+	if err != nil {
+		return err
+	}
+	stateBlock, err := NewSqliteStateBlockTable(db)
+	if err != nil {
+		return err
+	}
+	stateSnapshot, err := NewSqliteStateSnapshotTable(db)
+	if err != nil {
+		return err
+	}
+	prevEvents, err := NewSqlitePrevEventsTable(db)
+	if err != nil {
+		return err
+	}
+	roomAliases, err := NewSqliteRoomAliasesTable(db)
+	if err != nil {
+		return err
+	}
+	invites, err := NewSqliteInvitesTable(db)
+	if err != nil {
+		return err
+	}
+	membership, err := NewSqliteMembershipTable(db)
+	if err != nil {
+		return err
+	}
+	published, err := NewSqlitePublishedTable(db)
+	if err != nil {
+		return err
+	}
+	redactions, err := NewSqliteRedactionsTable(db)
+	if err != nil {
+		return err
+	}
+	d.Database = shared.Database{
+		DB:                         db,
+		Cache:                      cache,
+		Writer:                     sqlutil.NewExclusiveWriter(),
+		EventsTable:                events,
+		EventTypesTable:            eventTypes,
+		EventStateKeysTable:        eventStateKeys,
+		EventJSONTable:             eventJSON,
+		RoomsTable:                 rooms,
+		TransactionsTable:          transactions,
+		StateBlockTable:            stateBlock,
+		StateSnapshotTable:         stateSnapshot,
+		PrevEventsTable:            prevEvents,
+		RoomAliasesTable:           roomAliases,
+		InvitesTable:               invites,
+		MembershipTable:            membership,
+		PublishedTable:             published,
+		RedactionsTable:            redactions,
+		GetLatestEventsForUpdateFn: d.GetLatestEventsForUpdate,
+	}
+	return nil
+}
+
+func (d *Database) SupportsConcurrentRoomInputs() bool {
+	// This isn't supported in SQLite mode yet because of issues with
+	// database locks.
+	// TODO: Look at this again - the problem is probably to do with
+	// the membership updaters and latest events updaters.
+	return false
+}
+
+func (d *Database) GetLatestEventsForUpdate(
+	ctx context.Context, roomInfo types.RoomInfo,
+) (*shared.LatestEventsUpdater, error) {
+	// TODO: Do not use transactions. We should be holding open this transaction but we cannot have
+	// multiple write transactions on sqlite. The code will perform additional
+	// write transactions independent of this one which will consistently cause
+	// 'database is locked' errors. As sqlite doesn't support multi-process on the
+	// same DB anyway, and we only execute updates sequentially, the only worries
+	// are for rolling back when things go wrong. (atomicity)
+	return shared.NewLatestEventsUpdater(ctx, &d.Database, nil, roomInfo)
+}
+
+func (d *Database) MembershipUpdater(
+	ctx context.Context, roomID, targetUserID string,
+	targetLocal bool, roomVersion gomatrixserverlib.RoomVersion,
+) (*shared.MembershipUpdater, error) {
+	// TODO: Do not use transactions. We should be holding open this transaction but we cannot have
+	// multiple write transactions on sqlite. The code will perform additional
+	// write transactions independent of this one which will consistently cause
+	// 'database is locked' errors. As sqlite doesn't support multi-process on the
+	// same DB anyway, and we only execute updates sequentially, the only worries
+	// are for rolling back when things go wrong. (atomicity)
+	return shared.NewMembershipUpdater(ctx, &d.Database, nil, roomID, targetUserID, targetLocal, roomVersion)
+}

roomserver/storage/cosmosdb/transactions_table.go

@@ -0,0 +1,91 @@
+// Copyright 2017-2018 New Vector Ltd
+// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/roomserver/storage/shared"
+	"github.com/matrix-org/dendrite/roomserver/storage/tables"
+)
+
+const transactionsSchema = `
+	CREATE TABLE IF NOT EXISTS roomserver_transactions (
+		transaction_id TEXT NOT NULL,
+		session_id INTEGER NOT NULL,
+		user_id TEXT NOT NULL,
+		event_id TEXT NOT NULL,
+		PRIMARY KEY (transaction_id, session_id, user_id)
+	);
+`
+const insertTransactionSQL = `
+	INSERT INTO roomserver_transactions (transaction_id, session_id, user_id, event_id)
+	  VALUES ($1, $2, $3, $4)
+`
+
+const selectTransactionEventIDSQL = `
+	SELECT event_id FROM roomserver_transactions
+	  WHERE transaction_id = $1 AND session_id = $2 AND user_id = $3
+`
+
+type transactionStatements struct {
+	db                           *sql.DB
+	insertTransactionStmt        *sql.Stmt
+	selectTransactionEventIDStmt *sql.Stmt
+}
+
+func NewSqliteTransactionsTable(db *sql.DB) (tables.Transactions, error) {
+	s := &transactionStatements{
+		db: db,
+	}
+	_, err := db.Exec(transactionsSchema)
+	if err != nil {
+		return nil, err
+	}
+
+	return s, shared.StatementList{
+		{&s.insertTransactionStmt, insertTransactionSQL},
+		{&s.selectTransactionEventIDStmt, selectTransactionEventIDSQL},
+	}.Prepare(db)
+}
+
+func (s *transactionStatements) InsertTransaction(
+	ctx context.Context, txn *sql.Tx,
+	transactionID string,
+	sessionID int64,
+	userID string,
+	eventID string,
+) error {
+	stmt := sqlutil.TxStmt(txn, s.insertTransactionStmt)
+	_, err := stmt.ExecContext(
+		ctx, transactionID, sessionID, userID, eventID,
+	)
+	return err
+}
+
+func (s *transactionStatements) SelectTransactionEventID(
+	ctx context.Context,
+	transactionID string,
+	sessionID int64,
+	userID string,
+) (eventID string, err error) {
+	err = s.selectTransactionEventIDStmt.QueryRowContext(
+		ctx, transactionID, sessionID, userID,
+	).Scan(&eventID)
+	return
+}

roomserver/storage/storage.go

@@ -20,6 +20,7 @@ import (
 	"fmt"
 
 	"github.com/matrix-org/dendrite/internal/caching"
+	"github.com/matrix-org/dendrite/roomserver/storage/cosmosdb"
 	"github.com/matrix-org/dendrite/roomserver/storage/postgres"
 	"github.com/matrix-org/dendrite/roomserver/storage/sqlite3"
 	"github.com/matrix-org/dendrite/setup/config"
@@ -28,6 +29,8 @@ import (
 // Open opens a database connection.
 func Open(dbProperties *config.DatabaseOptions, cache caching.RoomServerCaches) (Database, error) {
 	switch {
+	case dbProperties.ConnectionString.IsCosmosDB():
+		return cosmosdb.Open(dbProperties, cache)
 	case dbProperties.ConnectionString.IsSQLite():
 		return sqlite3.Open(dbProperties, cache)
 	case dbProperties.ConnectionString.IsPostgres():

roomserver/storage/storage_wasm.go

@@ -25,6 +25,8 @@ import (
 // NewPublicRoomsServerDatabase opens a database connection.
 func Open(dbProperties *config.DatabaseOptions, cache caching.RoomServerCaches) (Database, error) {
 	switch {
+	case dbProperties.ConnectionString.IsCosmosDB():
+		return nil, fmt.Errorf("can't use CosmosDB implementation")
 	case dbProperties.ConnectionString.IsSQLite():
 		return sqlite3.Open(dbProperties, cache)
 	case dbProperties.ConnectionString.IsPostgres():

setup/config/config.go

@@ -139,6 +139,11 @@ func (d DataSource) IsPostgres() bool {
 	return !d.IsSQLite()
 }
 
+func (d DataSource) IsCosmosDB() bool {
+	// commented line may not always be true?
+	return strings.HasPrefix(string(d), "cosmosdb:")
+}
+
 // A Topic in kafka.
 type Topic string
 

setup/mscs/msc2836/storage.go

@@ -59,6 +59,9 @@ type DB struct {
 
 // NewDatabase loads the database for msc2836
 func NewDatabase(dbOpts *config.DatabaseOptions) (Database, error) {
+	if dbOpts.ConnectionString.IsCosmosDB() {
+		return newCosmosDBDatabase(dbOpts)
+	}
 	if dbOpts.ConnectionString.IsPostgres() {
 		return newPostgresDatabase(dbOpts)
 	}
@@ -225,6 +228,86 @@ func newSQLiteDatabase(dbOpts *config.DatabaseOptions) (Database, error) {
 	return &d, nil
 }
 
+func newCosmosDBDatabase(dbOpts *config.DatabaseOptions) (Database, error) {
+	d := DB{
+		writer: sqlutil.NewExclusiveWriter(),
+	}
+	var err error
+	if d.db, err = sqlutil.Open(dbOpts); err != nil {
+		return nil, err
+	}
+	_, err = d.db.Exec(`
+	CREATE TABLE IF NOT EXISTS msc2836_edges (
+		parent_event_id TEXT NOT NULL,
+		child_event_id TEXT NOT NULL,
+		rel_type TEXT NOT NULL,
+		parent_room_id TEXT NOT NULL,
+		parent_servers TEXT NOT NULL,
+		UNIQUE (parent_event_id, child_event_id, rel_type)
+	);
+
+	CREATE TABLE IF NOT EXISTS msc2836_nodes (
+		event_id TEXT PRIMARY KEY NOT NULL,
+		origin_server_ts BIGINT NOT NULL,
+		room_id TEXT NOT NULL,
+		unsigned_children_count BIGINT NOT NULL,
+		unsigned_children_hash TEXT NOT NULL,
+		explored SMALLINT NOT NULL
+	);
+	`)
+	if err != nil {
+		return nil, err
+	}
+	if d.insertEdgeStmt, err = d.db.Prepare(`
+		INSERT INTO msc2836_edges(parent_event_id, child_event_id, rel_type, parent_room_id, parent_servers)
+		VALUES($1, $2, $3, $4, $5)
+		ON CONFLICT (parent_event_id, child_event_id, rel_type) DO NOTHING
+	`); err != nil {
+		return nil, err
+	}
+	if d.insertNodeStmt, err = d.db.Prepare(`
+		INSERT INTO msc2836_nodes(event_id, origin_server_ts, room_id, unsigned_children_count, unsigned_children_hash, explored)
+		VALUES($1, $2, $3, $4, $5, $6)
+		ON CONFLICT DO NOTHING
+	`); err != nil {
+		return nil, err
+	}
+	selectChildrenQuery := `
+	SELECT child_event_id, origin_server_ts, room_id FROM msc2836_edges
+	LEFT JOIN msc2836_nodes ON msc2836_edges.child_event_id = msc2836_nodes.event_id
+	WHERE parent_event_id = $1 AND rel_type = $2
+	ORDER BY origin_server_ts
+	`
+	if d.selectChildrenForParentOldestFirstStmt, err = d.db.Prepare(selectChildrenQuery + "ASC"); err != nil {
+		return nil, err
+	}
+	if d.selectChildrenForParentRecentFirstStmt, err = d.db.Prepare(selectChildrenQuery + "DESC"); err != nil {
+		return nil, err
+	}
+	if d.selectParentForChildStmt, err = d.db.Prepare(`
+		SELECT parent_event_id, parent_room_id FROM msc2836_edges
+		WHERE child_event_id = $1 AND rel_type = $2
+	`); err != nil {
+		return nil, err
+	}
+	if d.updateChildMetadataStmt, err = d.db.Prepare(`
+		UPDATE msc2836_nodes SET unsigned_children_count=$1, unsigned_children_hash=$2, explored=$3 WHERE event_id=$4
+	`); err != nil {
+		return nil, err
+	}
+	if d.selectChildMetadataStmt, err = d.db.Prepare(`
+		SELECT unsigned_children_count, unsigned_children_hash, explored FROM msc2836_nodes WHERE event_id=$1
+	`); err != nil {
+		return nil, err
+	}
+	if d.updateChildMetadataExploredStmt, err = d.db.Prepare(`
+		UPDATE msc2836_nodes SET explored=$1 WHERE event_id=$2
+	`); err != nil {
+		return nil, err
+	}
+	return &d, nil
+}
+
 func (p *DB) StoreRelation(ctx context.Context, ev *gomatrixserverlib.HeaderedEvent) error {
 	parent, child, relType := parentChildEventIDs(ev)
 	if parent == "" || child == "" {

setup/mscs/msc2946/storage.go

@@ -47,6 +47,9 @@ type DB struct {
 
 // NewDatabase loads the database for msc2836
 func NewDatabase(dbOpts *config.DatabaseOptions) (Database, error) {
+	if dbOpts.ConnectionString.IsCosmosDB() {
+		return newCosmosDBDatabase(dbOpts)
+	}
 	if dbOpts.ConnectionString.IsPostgres() {
 		return newPostgresDatabase(dbOpts)
 	}
@@ -133,6 +136,46 @@ func newSQLiteDatabase(dbOpts *config.DatabaseOptions) (Database, error) {
 	return &d, err
 }
 
+func newCosmosDBDatabase(dbOpts *config.DatabaseOptions) (Database, error) {
+	d := DB{
+		writer: sqlutil.NewExclusiveWriter(),
+	}
+	var err error
+	if d.db, err = sqlutil.Open(dbOpts); err != nil {
+		return nil, err
+	}
+	_, err = d.db.Exec(`
+	CREATE TABLE IF NOT EXISTS msc2946_edges (
+		room_version TEXT NOT NULL,
+		-- the room ID of the event, the source of the arrow
+		source_room_id TEXT NOT NULL,
+		-- the target room ID, the arrow destination
+		dest_room_id TEXT NOT NULL,
+		-- the kind of relation, either child or parent (1,2)
+		rel_type SMALLINT NOT NULL,
+		event_json TEXT NOT NULL,
+		UNIQUE (source_room_id, dest_room_id, rel_type)
+	);
+	`)
+	if err != nil {
+		return nil, err
+	}
+	if d.insertEdgeStmt, err = d.db.Prepare(`
+		INSERT INTO msc2946_edges(room_version, source_room_id, dest_room_id, rel_type, event_json)
+		VALUES($1, $2, $3, $4, $5)
+		ON CONFLICT (source_room_id, dest_room_id, rel_type) DO UPDATE SET event_json = $5
+	`); err != nil {
+		return nil, err
+	}
+	if d.selectEdgesStmt, err = d.db.Prepare(`
+		SELECT room_version, event_json FROM msc2946_edges
+		WHERE source_room_id = $1 OR dest_room_id = $2
+	`); err != nil {
+		return nil, err
+	}
+	return &d, err
+}
+
 func (d *DB) StoreReference(ctx context.Context, he *gomatrixserverlib.HeaderedEvent) error {
 	target := SpaceTarget(he)
 	if target == "" {

signingkeyserver/storage/cosmosdb/keydb.go

@@ -0,0 +1,99 @@
+// Copyright 2017-2018 New Vector Ltd
+// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+
+	"golang.org/x/crypto/ed25519"
+
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/setup/config"
+	"github.com/matrix-org/gomatrixserverlib"
+
+	_ "github.com/mattn/go-sqlite3"
+)
+
+// A Database implements gomatrixserverlib.KeyDatabase and is used to store
+// the public keys for other matrix servers.
+type Database struct {
+	writer     sqlutil.Writer
+	statements serverKeyStatements
+}
+
+// NewDatabase prepares a new key database.
+// It creates the necessary tables if they don't already exist.
+// It prepares all the SQL statements that it will use.
+// Returns an error if there was a problem talking to the database.
+func NewDatabase(
+	dbProperties *config.DatabaseOptions,
+	serverName gomatrixserverlib.ServerName,
+	serverKey ed25519.PublicKey,
+	serverKeyID gomatrixserverlib.KeyID,
+) (*Database, error) {
+	db, err := sqlutil.Open(dbProperties)
+	if err != nil {
+		return nil, err
+	}
+	d := &Database{
+		writer: sqlutil.NewExclusiveWriter(),
+	}
+	err = d.statements.prepare(db, d.writer)
+	if err != nil {
+		return nil, err
+	}
+	if err != nil {
+		return nil, err
+	}
+	return d, nil
+}
+
+// FetcherName implements KeyFetcher
+func (d Database) FetcherName() string {
+	return "SqliteKeyDatabase"
+}
+
+// FetchKeys implements gomatrixserverlib.KeyDatabase
+func (d *Database) FetchKeys(
+	ctx context.Context,
+	requests map[gomatrixserverlib.PublicKeyLookupRequest]gomatrixserverlib.Timestamp,
+) (map[gomatrixserverlib.PublicKeyLookupRequest]gomatrixserverlib.PublicKeyLookupResult, error) {
+	return d.statements.bulkSelectServerKeys(ctx, requests)
+}
+
+// StoreKeys implements gomatrixserverlib.KeyDatabase
+func (d *Database) StoreKeys(
+	ctx context.Context,
+	keyMap map[gomatrixserverlib.PublicKeyLookupRequest]gomatrixserverlib.PublicKeyLookupResult,
+) error {
+	// TODO: Inserting all the keys within a single transaction may
+	// be more efficient since the transaction overhead can be quite
+	// high for a single insert statement.
+	var lastErr error
+	for request, keys := range keyMap {
+		if err := d.statements.upsertServerKeys(ctx, request, keys); err != nil {
+			// Rather than returning immediately on error we try to insert the
+			// remaining keys.
+			// Since we are inserting the keys outside of a transaction it is
+			// possible for some of the inserts to succeed even though some
+			// of the inserts have failed.
+			// Ensuring that we always insert all the keys we can means that
+			// this behaviour won't depend on the iteration order of the map.
+			lastErr = err
+		}
+	}
+	return lastErr
+}

signingkeyserver/storage/cosmosdb/server_key_table.go

@@ -0,0 +1,159 @@
+// Copyright 2017-2018 New Vector Ltd
+// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/gomatrixserverlib"
+)
+
+const serverKeysSchema = `
+-- A cache of signing keys downloaded from remote servers.
+CREATE TABLE IF NOT EXISTS keydb_server_keys (
+	-- The name of the matrix server the key is for.
+	server_name TEXT NOT NULL,
+	-- The ID of the server key.
+	server_key_id TEXT NOT NULL,
+	-- Combined server name and key ID separated by the ASCII unit separator
+	-- to make it easier to run bulk queries.
+	server_name_and_key_id TEXT NOT NULL,
+	-- When the key is valid until as a millisecond timestamp.
+	-- 0 if this is an expired key (in which case expired_ts will be non-zero)
+	valid_until_ts BIGINT NOT NULL,
+	-- When the key expired as a millisecond timestamp.
+	-- 0 if this is an active key (in which case valid_until_ts will be non-zero)
+	expired_ts BIGINT NOT NULL,
+	-- The base64-encoded public key.
+	server_key TEXT NOT NULL,
+	UNIQUE (server_name, server_key_id)
+);
+
+CREATE INDEX IF NOT EXISTS keydb_server_name_and_key_id ON keydb_server_keys (server_name_and_key_id);
+`
+
+const bulkSelectServerKeysSQL = "" +
+	"SELECT server_name, server_key_id, valid_until_ts, expired_ts, " +
+	"   server_key FROM keydb_server_keys" +
+	" WHERE server_name_and_key_id IN ($1)"
+
+const upsertServerKeysSQL = "" +
+	"INSERT INTO keydb_server_keys (server_name, server_key_id," +
+	" server_name_and_key_id, valid_until_ts, expired_ts, server_key)" +
+	" VALUES ($1, $2, $3, $4, $5, $6)" +
+	" ON CONFLICT (server_name, server_key_id)" +
+	" DO UPDATE SET valid_until_ts = $4, expired_ts = $5, server_key = $6"
+
+type serverKeyStatements struct {
+	db                       *sql.DB
+	writer                   sqlutil.Writer
+	bulkSelectServerKeysStmt *sql.Stmt
+	upsertServerKeysStmt     *sql.Stmt
+}
+
+func (s *serverKeyStatements) prepare(db *sql.DB, writer sqlutil.Writer) (err error) {
+	s.db = db
+	s.writer = writer
+	_, err = db.Exec(serverKeysSchema)
+	if err != nil {
+		return
+	}
+	if s.bulkSelectServerKeysStmt, err = db.Prepare(bulkSelectServerKeysSQL); err != nil {
+		return
+	}
+	if s.upsertServerKeysStmt, err = db.Prepare(upsertServerKeysSQL); err != nil {
+		return
+	}
+	return
+}
+
+func (s *serverKeyStatements) bulkSelectServerKeys(
+	ctx context.Context,
+	requests map[gomatrixserverlib.PublicKeyLookupRequest]gomatrixserverlib.Timestamp,
+) (map[gomatrixserverlib.PublicKeyLookupRequest]gomatrixserverlib.PublicKeyLookupResult, error) {
+	nameAndKeyIDs := make([]string, 0, len(requests))
+	for request := range requests {
+		nameAndKeyIDs = append(nameAndKeyIDs, nameAndKeyID(request))
+	}
+	results := make(map[gomatrixserverlib.PublicKeyLookupRequest]gomatrixserverlib.PublicKeyLookupResult, len(requests))
+	iKeyIDs := make([]interface{}, len(nameAndKeyIDs))
+	for i, v := range nameAndKeyIDs {
+		iKeyIDs[i] = v
+	}
+
+	err := sqlutil.RunLimitedVariablesQuery(
+		ctx, bulkSelectServerKeysSQL, s.db, iKeyIDs, sqlutil.SQLite3MaxVariables,
+		func(rows *sql.Rows) error {
+			for rows.Next() {
+				var serverName string
+				var keyID string
+				var key string
+				var validUntilTS int64
+				var expiredTS int64
+				if err := rows.Scan(&serverName, &keyID, &validUntilTS, &expiredTS, &key); err != nil {
+					return fmt.Errorf("bulkSelectServerKeys: %v", err)
+				}
+				r := gomatrixserverlib.PublicKeyLookupRequest{
+					ServerName: gomatrixserverlib.ServerName(serverName),
+					KeyID:      gomatrixserverlib.KeyID(keyID),
+				}
+				vk := gomatrixserverlib.VerifyKey{}
+				err := vk.Key.Decode(key)
+				if err != nil {
+					return fmt.Errorf("bulkSelectServerKeys: %v", err)
+				}
+				results[r] = gomatrixserverlib.PublicKeyLookupResult{
+					VerifyKey:    vk,
+					ValidUntilTS: gomatrixserverlib.Timestamp(validUntilTS),
+					ExpiredTS:    gomatrixserverlib.Timestamp(expiredTS),
+				}
+			}
+			return nil
+		},
+	)
+
+	if err != nil {
+		return nil, err
+	}
+	return results, nil
+}
+
+func (s *serverKeyStatements) upsertServerKeys(
+	ctx context.Context,
+	request gomatrixserverlib.PublicKeyLookupRequest,
+	key gomatrixserverlib.PublicKeyLookupResult,
+) error {
+	return s.writer.Do(s.db, nil, func(txn *sql.Tx) error {
+		stmt := sqlutil.TxStmt(txn, s.upsertServerKeysStmt)
+		_, err := stmt.ExecContext(
+			ctx,
+			string(request.ServerName),
+			string(request.KeyID),
+			nameAndKeyID(request),
+			key.ValidUntilTS,
+			key.ExpiredTS,
+			key.Key.Encode(),
+		)
+		return err
+	})
+}
+
+func nameAndKeyID(request gomatrixserverlib.PublicKeyLookupRequest) string {
+	return string(request.ServerName) + "\x1F" + string(request.KeyID)
+}

signingkeyserver/storage/keydb.go

@@ -22,6 +22,7 @@ import (
 	"golang.org/x/crypto/ed25519"
 
 	"github.com/matrix-org/dendrite/setup/config"
+	"github.com/matrix-org/dendrite/signingkeyserver/storage/cosmosdb"
 	"github.com/matrix-org/dendrite/signingkeyserver/storage/postgres"
 	"github.com/matrix-org/dendrite/signingkeyserver/storage/sqlite3"
 	"github.com/matrix-org/gomatrixserverlib"
@@ -35,6 +36,8 @@ func NewDatabase(
 	serverKeyID gomatrixserverlib.KeyID,
 ) (Database, error) {
 	switch {
+	case dbProperties.ConnectionString.IsCosmosDB():
+		return cosmosdb.NewDatabase(dbProperties, serverName, serverKey, serverKeyID)
 	case dbProperties.ConnectionString.IsSQLite():
 		return sqlite3.NewDatabase(dbProperties, serverName, serverKey, serverKeyID)
 	case dbProperties.ConnectionString.IsPostgres():

syncapi/storage/cosmosdb/account_data_table.go

@@ -0,0 +1,156 @@
+// Copyright 2017-2018 New Vector Ltd
+// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/syncapi/storage/tables"
+	"github.com/matrix-org/dendrite/syncapi/types"
+	"github.com/matrix-org/gomatrixserverlib"
+)
+
+const accountDataSchema = `
+CREATE TABLE IF NOT EXISTS syncapi_account_data_type (
+    id INTEGER PRIMARY KEY,
+    user_id TEXT NOT NULL,
+    room_id TEXT NOT NULL,
+    type TEXT NOT NULL,
+    UNIQUE (user_id, room_id, type)
+);
+`
+
+const insertAccountDataSQL = "" +
+	"INSERT INTO syncapi_account_data_type (id, user_id, room_id, type) VALUES ($1, $2, $3, $4)" +
+	" ON CONFLICT (user_id, room_id, type) DO UPDATE" +
+	" SET id = $5"
+
+const selectAccountDataInRangeSQL = "" +
+	"SELECT room_id, type FROM syncapi_account_data_type" +
+	" WHERE user_id = $1 AND id > $2 AND id <= $3" +
+	" ORDER BY id ASC"
+
+const selectMaxAccountDataIDSQL = "" +
+	"SELECT MAX(id) FROM syncapi_account_data_type"
+
+type accountDataStatements struct {
+	db                           *sql.DB
+	streamIDStatements           *streamIDStatements
+	insertAccountDataStmt        *sql.Stmt
+	selectMaxAccountDataIDStmt   *sql.Stmt
+	selectAccountDataInRangeStmt *sql.Stmt
+}
+
+func NewSqliteAccountDataTable(db *sql.DB, streamID *streamIDStatements) (tables.AccountData, error) {
+	s := &accountDataStatements{
+		db:                 db,
+		streamIDStatements: streamID,
+	}
+	_, err := db.Exec(accountDataSchema)
+	if err != nil {
+		return nil, err
+	}
+	if s.insertAccountDataStmt, err = db.Prepare(insertAccountDataSQL); err != nil {
+		return nil, err
+	}
+	if s.selectMaxAccountDataIDStmt, err = db.Prepare(selectMaxAccountDataIDSQL); err != nil {
+		return nil, err
+	}
+	if s.selectAccountDataInRangeStmt, err = db.Prepare(selectAccountDataInRangeSQL); err != nil {
+		return nil, err
+	}
+	return s, nil
+}
+
+func (s *accountDataStatements) InsertAccountData(
+	ctx context.Context, txn *sql.Tx,
+	userID, roomID, dataType string,
+) (pos types.StreamPosition, err error) {
+	pos, err = s.streamIDStatements.nextAccountDataID(ctx, txn)
+	if err != nil {
+		return
+	}
+	_, err = sqlutil.TxStmt(txn, s.insertAccountDataStmt).ExecContext(ctx, pos, userID, roomID, dataType, pos)
+	return
+}
+
+func (s *accountDataStatements) SelectAccountDataInRange(
+	ctx context.Context,
+	userID string,
+	r types.Range,
+	accountDataFilterPart *gomatrixserverlib.EventFilter,
+) (data map[string][]string, err error) {
+	data = make(map[string][]string)
+
+	rows, err := s.selectAccountDataInRangeStmt.QueryContext(ctx, userID, r.Low(), r.High())
+	if err != nil {
+		return
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "selectAccountDataInRange: rows.close() failed")
+
+	var entries int
+
+	for rows.Next() {
+		var dataType string
+		var roomID string
+
+		if err = rows.Scan(&roomID, &dataType); err != nil {
+			return
+		}
+
+		// check if we should add this by looking at the filter.
+		// It would be nice if we could do this in SQL-land, but the mix of variadic
+		// and positional parameters makes the query annoyingly hard to do, it's easier
+		// and clearer to do it in Go-land. If there are no filters for [not]types then
+		// this gets skipped.
+		for _, includeType := range accountDataFilterPart.Types {
+			if includeType != dataType { // TODO: wildcard support
+				continue
+			}
+		}
+		for _, excludeType := range accountDataFilterPart.NotTypes {
+			if excludeType == dataType { // TODO: wildcard support
+				continue
+			}
+		}
+
+		if len(data[roomID]) > 0 {
+			data[roomID] = append(data[roomID], dataType)
+		} else {
+			data[roomID] = []string{dataType}
+		}
+		entries++
+		if entries >= accountDataFilterPart.Limit {
+			break
+		}
+	}
+
+	return data, nil
+}
+
+func (s *accountDataStatements) SelectMaxAccountDataID(
+	ctx context.Context, txn *sql.Tx,
+) (id int64, err error) {
+	var nullableID sql.NullInt64
+	err = sqlutil.TxStmt(txn, s.selectMaxAccountDataIDStmt).QueryRowContext(ctx).Scan(&nullableID)
+	if nullableID.Valid {
+		id = nullableID.Int64
+	}
+	return
+}

syncapi/storage/cosmosdb/backwards_extremities_table.go

@@ -0,0 +1,125 @@
+// Copyright 2018 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/syncapi/storage/tables"
+)
+
+const backwardExtremitiesSchema = `
+-- Stores output room events received from the roomserver.
+CREATE TABLE IF NOT EXISTS syncapi_backward_extremities (
+	-- The 'room_id' key for the event.
+	room_id TEXT NOT NULL,
+	-- The event ID for the last known event. This is the backwards extremity.
+	event_id TEXT NOT NULL,
+	-- The prev_events for the last known event. This is used to update extremities.
+	prev_event_id TEXT NOT NULL,
+	PRIMARY KEY(room_id, event_id, prev_event_id)
+);
+`
+
+const insertBackwardExtremitySQL = "" +
+	"INSERT INTO syncapi_backward_extremities (room_id, event_id, prev_event_id)" +
+	" VALUES ($1, $2, $3)" +
+	" ON CONFLICT (room_id, event_id, prev_event_id) DO NOTHING"
+
+const selectBackwardExtremitiesForRoomSQL = "" +
+	"SELECT event_id, prev_event_id FROM syncapi_backward_extremities WHERE room_id = $1"
+
+const deleteBackwardExtremitySQL = "" +
+	"DELETE FROM syncapi_backward_extremities WHERE room_id = $1 AND prev_event_id = $2"
+
+const deleteBackwardExtremitiesForRoomSQL = "" +
+	"DELETE FROM syncapi_backward_extremities WHERE room_id = $1"
+
+type backwardExtremitiesStatements struct {
+	db                                   *sql.DB
+	insertBackwardExtremityStmt          *sql.Stmt
+	selectBackwardExtremitiesForRoomStmt *sql.Stmt
+	deleteBackwardExtremityStmt          *sql.Stmt
+	deleteBackwardExtremitiesForRoomStmt *sql.Stmt
+}
+
+func NewSqliteBackwardsExtremitiesTable(db *sql.DB) (tables.BackwardsExtremities, error) {
+	s := &backwardExtremitiesStatements{
+		db: db,
+	}
+	_, err := db.Exec(backwardExtremitiesSchema)
+	if err != nil {
+		return nil, err
+	}
+	if s.insertBackwardExtremityStmt, err = db.Prepare(insertBackwardExtremitySQL); err != nil {
+		return nil, err
+	}
+	if s.selectBackwardExtremitiesForRoomStmt, err = db.Prepare(selectBackwardExtremitiesForRoomSQL); err != nil {
+		return nil, err
+	}
+	if s.deleteBackwardExtremityStmt, err = db.Prepare(deleteBackwardExtremitySQL); err != nil {
+		return nil, err
+	}
+	if s.deleteBackwardExtremitiesForRoomStmt, err = db.Prepare(deleteBackwardExtremitiesForRoomSQL); err != nil {
+		return nil, err
+	}
+	return s, nil
+}
+
+func (s *backwardExtremitiesStatements) InsertsBackwardExtremity(
+	ctx context.Context, txn *sql.Tx, roomID, eventID string, prevEventID string,
+) (err error) {
+	_, err = sqlutil.TxStmt(txn, s.insertBackwardExtremityStmt).ExecContext(ctx, roomID, eventID, prevEventID)
+	return err
+}
+
+func (s *backwardExtremitiesStatements) SelectBackwardExtremitiesForRoom(
+	ctx context.Context, roomID string,
+) (bwExtrems map[string][]string, err error) {
+	rows, err := s.selectBackwardExtremitiesForRoomStmt.QueryContext(ctx, roomID)
+	if err != nil {
+		return
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "selectBackwardExtremitiesForRoom: rows.close() failed")
+
+	bwExtrems = make(map[string][]string)
+	for rows.Next() {
+		var eID string
+		var prevEventID string
+		if err = rows.Scan(&eID, &prevEventID); err != nil {
+			return
+		}
+		bwExtrems[eID] = append(bwExtrems[eID], prevEventID)
+	}
+
+	return bwExtrems, rows.Err()
+}
+
+func (s *backwardExtremitiesStatements) DeleteBackwardExtremity(
+	ctx context.Context, txn *sql.Tx, roomID, knownEventID string,
+) (err error) {
+	_, err = sqlutil.TxStmt(txn, s.deleteBackwardExtremityStmt).ExecContext(ctx, roomID, knownEventID)
+	return err
+}
+
+func (s *backwardExtremitiesStatements) DeleteBackwardExtremitiesForRoom(
+	ctx context.Context, txn *sql.Tx, roomID string,
+) (err error) {
+	_, err = sqlutil.TxStmt(txn, s.deleteBackwardExtremitiesForRoomStmt).ExecContext(ctx, roomID)
+	return err
+}

syncapi/storage/cosmosdb/current_room_state_table.go

@@ -0,0 +1,324 @@
+// Copyright 2017-2018 New Vector Ltd
+// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+	"encoding/json"
+	"fmt"
+	"strings"
+
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/syncapi/storage/tables"
+	"github.com/matrix-org/dendrite/syncapi/types"
+	"github.com/matrix-org/gomatrixserverlib"
+)
+
+const currentRoomStateSchema = `
+-- Stores the current room state for every room.
+CREATE TABLE IF NOT EXISTS syncapi_current_room_state (
+    room_id TEXT NOT NULL,
+    event_id TEXT NOT NULL,
+    type TEXT NOT NULL,
+    sender TEXT NOT NULL,
+    contains_url BOOL NOT NULL DEFAULT false,
+    state_key TEXT NOT NULL,
+    headered_event_json TEXT NOT NULL,
+    membership TEXT,
+    added_at BIGINT,
+    UNIQUE (room_id, type, state_key)
+);
+-- for event deletion
+CREATE UNIQUE INDEX IF NOT EXISTS syncapi_event_id_idx ON syncapi_current_room_state(event_id, room_id, type, sender, contains_url);
+-- for querying membership states of users
+-- CREATE INDEX IF NOT EXISTS syncapi_membership_idx ON syncapi_current_room_state(type, state_key, membership) WHERE membership IS NOT NULL AND membership != 'leave';
+-- for querying state by event IDs
+CREATE UNIQUE INDEX IF NOT EXISTS syncapi_current_room_state_eventid_idx ON syncapi_current_room_state(event_id);
+`
+
+const upsertRoomStateSQL = "" +
+	"INSERT INTO syncapi_current_room_state (room_id, event_id, type, sender, contains_url, state_key, headered_event_json, membership, added_at)" +
+	" VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9)" +
+	" ON CONFLICT (room_id, type, state_key)" +
+	" DO UPDATE SET event_id = $2, sender=$4, contains_url=$5, headered_event_json = $7, membership = $8, added_at = $9"
+
+const deleteRoomStateByEventIDSQL = "" +
+	"DELETE FROM syncapi_current_room_state WHERE event_id = $1"
+
+const DeleteRoomStateForRoomSQL = "" +
+	"DELETE FROM syncapi_current_room_state WHERE event_id = $1"
+
+const selectRoomIDsWithMembershipSQL = "" +
+	"SELECT DISTINCT room_id FROM syncapi_current_room_state WHERE type = 'm.room.member' AND state_key = $1 AND membership = $2"
+
+const selectCurrentStateSQL = "" +
+	"SELECT event_id, headered_event_json FROM syncapi_current_room_state WHERE room_id = $1"
+	// WHEN, ORDER BY and LIMIT will be added by prepareWithFilter
+
+const selectJoinedUsersSQL = "" +
+	"SELECT room_id, state_key FROM syncapi_current_room_state WHERE type = 'm.room.member' AND membership = 'join'"
+
+const selectStateEventSQL = "" +
+	"SELECT headered_event_json FROM syncapi_current_room_state WHERE room_id = $1 AND type = $2 AND state_key = $3"
+
+const selectEventsWithEventIDsSQL = "" +
+	// TODO: The session_id and transaction_id blanks are here because otherwise
+	// the rowsToStreamEvents expects there to be exactly six columns. We need to
+	// figure out if these really need to be in the DB, and if so, we need a
+	// better permanent fix for this. - neilalexander, 2 Jan 2020
+	"SELECT event_id, added_at, headered_event_json, 0 AS session_id, false AS exclude_from_sync, '' AS transaction_id" +
+	" FROM syncapi_current_room_state WHERE event_id IN ($1)"
+
+type currentRoomStateStatements struct {
+	db                              *sql.DB
+	streamIDStatements              *streamIDStatements
+	upsertRoomStateStmt             *sql.Stmt
+	deleteRoomStateByEventIDStmt    *sql.Stmt
+	DeleteRoomStateForRoomStmt      *sql.Stmt
+	selectRoomIDsWithMembershipStmt *sql.Stmt
+	selectJoinedUsersStmt           *sql.Stmt
+	selectStateEventStmt            *sql.Stmt
+}
+
+func NewSqliteCurrentRoomStateTable(db *sql.DB, streamID *streamIDStatements) (tables.CurrentRoomState, error) {
+	s := &currentRoomStateStatements{
+		db:                 db,
+		streamIDStatements: streamID,
+	}
+	_, err := db.Exec(currentRoomStateSchema)
+	if err != nil {
+		return nil, err
+	}
+	if s.upsertRoomStateStmt, err = db.Prepare(upsertRoomStateSQL); err != nil {
+		return nil, err
+	}
+	if s.deleteRoomStateByEventIDStmt, err = db.Prepare(deleteRoomStateByEventIDSQL); err != nil {
+		return nil, err
+	}
+	if s.DeleteRoomStateForRoomStmt, err = db.Prepare(DeleteRoomStateForRoomSQL); err != nil {
+		return nil, err
+	}
+	if s.selectRoomIDsWithMembershipStmt, err = db.Prepare(selectRoomIDsWithMembershipSQL); err != nil {
+		return nil, err
+	}
+	if s.selectJoinedUsersStmt, err = db.Prepare(selectJoinedUsersSQL); err != nil {
+		return nil, err
+	}
+	if s.selectStateEventStmt, err = db.Prepare(selectStateEventSQL); err != nil {
+		return nil, err
+	}
+	return s, nil
+}
+
+// JoinedMemberLists returns a map of room ID to a list of joined user IDs.
+func (s *currentRoomStateStatements) SelectJoinedUsers(
+	ctx context.Context,
+) (map[string][]string, error) {
+	rows, err := s.selectJoinedUsersStmt.QueryContext(ctx)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "selectJoinedUsers: rows.close() failed")
+
+	result := make(map[string][]string)
+	for rows.Next() {
+		var roomID string
+		var userID string
+		if err := rows.Scan(&roomID, &userID); err != nil {
+			return nil, err
+		}
+		users := result[roomID]
+		users = append(users, userID)
+		result[roomID] = users
+	}
+	return result, nil
+}
+
+// SelectRoomIDsWithMembership returns the list of room IDs which have the given user in the given membership state.
+func (s *currentRoomStateStatements) SelectRoomIDsWithMembership(
+	ctx context.Context,
+	txn *sql.Tx,
+	userID string,
+	membership string, // nolint: unparam
+) ([]string, error) {
+	stmt := sqlutil.TxStmt(txn, s.selectRoomIDsWithMembershipStmt)
+	rows, err := stmt.QueryContext(ctx, userID, membership)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "selectRoomIDsWithMembership: rows.close() failed")
+
+	var result []string
+	for rows.Next() {
+		var roomID string
+		if err := rows.Scan(&roomID); err != nil {
+			return nil, err
+		}
+		result = append(result, roomID)
+	}
+	return result, nil
+}
+
+// CurrentState returns all the current state events for the given room.
+func (s *currentRoomStateStatements) SelectCurrentState(
+	ctx context.Context, txn *sql.Tx, roomID string,
+	stateFilter *gomatrixserverlib.StateFilter,
+	excludeEventIDs []string,
+) ([]*gomatrixserverlib.HeaderedEvent, error) {
+	stmt, params, err := prepareWithFilters(
+		s.db, txn, selectCurrentStateSQL,
+		[]interface{}{
+			roomID,
+		},
+		stateFilter.Senders, stateFilter.NotSenders,
+		stateFilter.Types, stateFilter.NotTypes,
+		excludeEventIDs, stateFilter.Limit, FilterOrderNone,
+	)
+	if err != nil {
+		return nil, fmt.Errorf("s.prepareWithFilters: %w", err)
+	}
+
+	rows, err := stmt.QueryContext(ctx, params...)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "selectCurrentState: rows.close() failed")
+
+	return rowsToEvents(rows)
+}
+
+func (s *currentRoomStateStatements) DeleteRoomStateByEventID(
+	ctx context.Context, txn *sql.Tx, eventID string,
+) error {
+	stmt := sqlutil.TxStmt(txn, s.deleteRoomStateByEventIDStmt)
+	_, err := stmt.ExecContext(ctx, eventID)
+	return err
+}
+
+func (s *currentRoomStateStatements) DeleteRoomStateForRoom(
+	ctx context.Context, txn *sql.Tx, roomID string,
+) error {
+	stmt := sqlutil.TxStmt(txn, s.DeleteRoomStateForRoomStmt)
+	_, err := stmt.ExecContext(ctx, roomID)
+	return err
+}
+
+func (s *currentRoomStateStatements) UpsertRoomState(
+	ctx context.Context, txn *sql.Tx,
+	event *gomatrixserverlib.HeaderedEvent, membership *string, addedAt types.StreamPosition,
+) error {
+	// Parse content as JSON and search for an "url" key
+	containsURL := false
+	var content map[string]interface{}
+	if json.Unmarshal(event.Content(), &content) != nil {
+		// Set containsURL to true if url is present
+		_, containsURL = content["url"]
+	}
+
+	headeredJSON, err := json.Marshal(event)
+	if err != nil {
+		return err
+	}
+
+	// upsert state event
+	stmt := sqlutil.TxStmt(txn, s.upsertRoomStateStmt)
+	_, err = stmt.ExecContext(
+		ctx,
+		event.RoomID(),
+		event.EventID(),
+		event.Type(),
+		event.Sender(),
+		containsURL,
+		*event.StateKey(),
+		headeredJSON,
+		membership,
+		addedAt,
+	)
+	return err
+}
+
+func minOfInts(a, b int) int {
+	if a <= b {
+		return a
+	}
+	return b
+}
+
+func (s *currentRoomStateStatements) SelectEventsWithEventIDs(
+	ctx context.Context, txn *sql.Tx, eventIDs []string,
+) ([]types.StreamEvent, error) {
+	iEventIDs := make([]interface{}, len(eventIDs))
+	for k, v := range eventIDs {
+		iEventIDs[k] = v
+	}
+	res := make([]types.StreamEvent, 0, len(eventIDs))
+	var start int
+	for start < len(eventIDs) {
+		n := minOfInts(len(eventIDs)-start, 999)
+		query := strings.Replace(selectEventsWithEventIDsSQL, "($1)", sqlutil.QueryVariadic(n), 1)
+		rows, err := txn.QueryContext(ctx, query, iEventIDs[start:start+n]...)
+		if err != nil {
+			return nil, err
+		}
+		start = start + n
+		events, err := rowsToStreamEvents(rows)
+		internal.CloseAndLogIfError(ctx, rows, "selectEventsWithEventIDs: rows.close() failed")
+		if err != nil {
+			return nil, err
+		}
+		res = append(res, events...)
+	}
+	return res, nil
+}
+
+func rowsToEvents(rows *sql.Rows) ([]*gomatrixserverlib.HeaderedEvent, error) {
+	result := []*gomatrixserverlib.HeaderedEvent{}
+	for rows.Next() {
+		var eventID string
+		var eventBytes []byte
+		if err := rows.Scan(&eventID, &eventBytes); err != nil {
+			return nil, err
+		}
+		// TODO: Handle redacted events
+		var ev gomatrixserverlib.HeaderedEvent
+		if err := ev.UnmarshalJSONWithEventID(eventBytes, eventID); err != nil {
+			return nil, err
+		}
+		result = append(result, &ev)
+	}
+	return result, nil
+}
+
+func (s *currentRoomStateStatements) SelectStateEvent(
+	ctx context.Context, roomID, evType, stateKey string,
+) (*gomatrixserverlib.HeaderedEvent, error) {
+	stmt := s.selectStateEventStmt
+	var res []byte
+	err := stmt.QueryRowContext(ctx, roomID, evType, stateKey).Scan(&res)
+	if err == sql.ErrNoRows {
+		return nil, nil
+	}
+	if err != nil {
+		return nil, err
+	}
+	var ev gomatrixserverlib.HeaderedEvent
+	if err = json.Unmarshal(res, &ev); err != nil {
+		return nil, err
+	}
+	return &ev, err
+}

syncapi/storage/cosmosdb/filter_table.go

@@ -0,0 +1,140 @@
+// Copyright 2017 Jan Christian Grünhage
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+	"encoding/json"
+	"fmt"
+
+	"github.com/matrix-org/dendrite/syncapi/storage/tables"
+	"github.com/matrix-org/gomatrixserverlib"
+)
+
+const filterSchema = `
+-- Stores data about filters
+CREATE TABLE IF NOT EXISTS syncapi_filter (
+	-- The filter
+	filter TEXT NOT NULL,
+	-- The ID
+	id INTEGER PRIMARY KEY AUTOINCREMENT,
+	-- The localpart of the Matrix user ID associated to this filter
+	localpart TEXT NOT NULL,
+
+	UNIQUE (id, localpart)
+);
+
+CREATE INDEX IF NOT EXISTS syncapi_filter_localpart ON syncapi_filter(localpart);
+`
+
+const selectFilterSQL = "" +
+	"SELECT filter FROM syncapi_filter WHERE localpart = $1 AND id = $2"
+
+const selectFilterIDByContentSQL = "" +
+	"SELECT id FROM syncapi_filter WHERE localpart = $1 AND filter = $2"
+
+const insertFilterSQL = "" +
+	"INSERT INTO syncapi_filter (filter, localpart) VALUES ($1, $2)"
+
+type filterStatements struct {
+	db                          *sql.DB
+	selectFilterStmt            *sql.Stmt
+	selectFilterIDByContentStmt *sql.Stmt
+	insertFilterStmt            *sql.Stmt
+}
+
+func NewSqliteFilterTable(db *sql.DB) (tables.Filter, error) {
+	_, err := db.Exec(filterSchema)
+	if err != nil {
+		return nil, err
+	}
+	s := &filterStatements{
+		db: db,
+	}
+	if s.selectFilterStmt, err = db.Prepare(selectFilterSQL); err != nil {
+		return nil, err
+	}
+	if s.selectFilterIDByContentStmt, err = db.Prepare(selectFilterIDByContentSQL); err != nil {
+		return nil, err
+	}
+	if s.insertFilterStmt, err = db.Prepare(insertFilterSQL); err != nil {
+		return nil, err
+	}
+	return s, nil
+}
+
+func (s *filterStatements) SelectFilter(
+	ctx context.Context, localpart string, filterID string,
+) (*gomatrixserverlib.Filter, error) {
+	// Retrieve filter from database (stored as canonical JSON)
+	var filterData []byte
+	err := s.selectFilterStmt.QueryRowContext(ctx, localpart, filterID).Scan(&filterData)
+	if err != nil {
+		return nil, err
+	}
+
+	// Unmarshal JSON into Filter struct
+	filter := gomatrixserverlib.DefaultFilter()
+	if err = json.Unmarshal(filterData, &filter); err != nil {
+		return nil, err
+	}
+	return &filter, nil
+}
+
+func (s *filterStatements) InsertFilter(
+	ctx context.Context, filter *gomatrixserverlib.Filter, localpart string,
+) (filterID string, err error) {
+	var existingFilterID string
+
+	// Serialise json
+	filterJSON, err := json.Marshal(filter)
+	if err != nil {
+		return "", err
+	}
+	// Remove whitespaces and sort JSON data
+	// needed to prevent from inserting the same filter multiple times
+	filterJSON, err = gomatrixserverlib.CanonicalJSON(filterJSON)
+	if err != nil {
+		return "", err
+	}
+
+	// Check if filter already exists in the database using its localpart and content
+	//
+	// This can result in a race condition when two clients try to insert the
+	// same filter and localpart at the same time, however this is not a
+	// problem as both calls will result in the same filterID
+	err = s.selectFilterIDByContentStmt.QueryRowContext(ctx,
+		localpart, filterJSON).Scan(&existingFilterID)
+	if err != nil && err != sql.ErrNoRows {
+		return "", err
+	}
+	// If it does, return the existing ID
+	if existingFilterID != "" {
+		return existingFilterID, nil
+	}
+
+	// Otherwise insert the filter and return the new ID
+	res, err := s.insertFilterStmt.ExecContext(ctx, filterJSON, localpart)
+	if err != nil {
+		return "", err
+	}
+	rowid, err := res.LastInsertId()
+	if err != nil {
+		return "", err
+	}
+	filterID = fmt.Sprintf("%d", rowid)
+	return
+}

syncapi/storage/cosmosdb/filtering.go

@@ -0,0 +1,82 @@
+package cosmosdb
+
+import (
+	"database/sql"
+	"fmt"
+
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+)
+
+type FilterOrder int
+
+const (
+	FilterOrderNone = iota
+	FilterOrderAsc
+	FilterOrderDesc
+)
+
+// prepareWithFilters returns a prepared statement with the
+// relevant filters included. It also includes an []interface{}
+// list of all the relevant parameters to pass straight to
+// QueryContext, QueryRowContext etc.
+// We don't take the filter object directly here because the
+// fields might come from either a StateFilter or an EventFilter,
+// and it's easier just to have the caller extract the relevant
+// parts.
+func prepareWithFilters(
+	db *sql.DB, txn *sql.Tx, query string, params []interface{},
+	senders, notsenders, types, nottypes []string, excludeEventIDs []string,
+	limit int, order FilterOrder,
+) (*sql.Stmt, []interface{}, error) {
+	offset := len(params)
+	if count := len(senders); count > 0 {
+		query += " AND sender IN " + sqlutil.QueryVariadicOffset(count, offset)
+		for _, v := range senders {
+			params, offset = append(params, v), offset+1
+		}
+	}
+	if count := len(notsenders); count > 0 {
+		query += " AND sender NOT IN " + sqlutil.QueryVariadicOffset(count, offset)
+		for _, v := range notsenders {
+			params, offset = append(params, v), offset+1
+		}
+	}
+	if count := len(types); count > 0 {
+		query += " AND type IN " + sqlutil.QueryVariadicOffset(count, offset)
+		for _, v := range types {
+			params, offset = append(params, v), offset+1
+		}
+	}
+	if count := len(nottypes); count > 0 {
+		query += " AND type NOT IN " + sqlutil.QueryVariadicOffset(count, offset)
+		for _, v := range nottypes {
+			params, offset = append(params, v), offset+1
+		}
+	}
+	if count := len(excludeEventIDs); count > 0 {
+		query += " AND event_id NOT IN " + sqlutil.QueryVariadicOffset(count, offset)
+		for _, v := range excludeEventIDs {
+			params, offset = append(params, v), offset+1
+		}
+	}
+	switch order {
+	case FilterOrderAsc:
+		query += " ORDER BY id ASC"
+	case FilterOrderDesc:
+		query += " ORDER BY id DESC"
+	}
+	query += fmt.Sprintf(" LIMIT $%d", offset+1)
+	params = append(params, limit)
+
+	var stmt *sql.Stmt
+	var err error
+	if txn != nil {
+		stmt, err = txn.Prepare(query)
+	} else {
+		stmt, err = db.Prepare(query)
+	}
+	if err != nil {
+		return nil, nil, fmt.Errorf("s.db.Prepare: %w", err)
+	}
+	return stmt, params, nil
+}

syncapi/storage/cosmosdb/invites_table.go

@@ -0,0 +1,185 @@
+// Copyright 2017-2018 New Vector Ltd
+// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+	"encoding/json"
+
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/syncapi/storage/tables"
+	"github.com/matrix-org/dendrite/syncapi/types"
+	"github.com/matrix-org/gomatrixserverlib"
+)
+
+const inviteEventsSchema = `
+CREATE TABLE IF NOT EXISTS syncapi_invite_events (
+	id INTEGER PRIMARY KEY,
+	event_id TEXT NOT NULL,
+	room_id TEXT NOT NULL,
+	target_user_id TEXT NOT NULL,
+	headered_event_json TEXT NOT NULL,
+	deleted BOOL NOT NULL
+);
+
+CREATE INDEX IF NOT EXISTS syncapi_invites_target_user_id_idx ON syncapi_invite_events (target_user_id, id);
+CREATE INDEX IF NOT EXISTS syncapi_invites_event_id_idx ON syncapi_invite_events (event_id);
+`
+
+const insertInviteEventSQL = "" +
+	"INSERT INTO syncapi_invite_events" +
+	" (id, room_id, event_id, target_user_id, headered_event_json, deleted)" +
+	" VALUES ($1, $2, $3, $4, $5, false)"
+
+const deleteInviteEventSQL = "" +
+	"UPDATE syncapi_invite_events SET deleted=true, id=$1 WHERE event_id = $2"
+
+const selectInviteEventsInRangeSQL = "" +
+	"SELECT room_id, headered_event_json, deleted FROM syncapi_invite_events" +
+	" WHERE target_user_id = $1 AND id > $2 AND id <= $3" +
+	" ORDER BY id DESC"
+
+const selectMaxInviteIDSQL = "" +
+	"SELECT MAX(id) FROM syncapi_invite_events"
+
+type inviteEventsStatements struct {
+	db                            *sql.DB
+	streamIDStatements            *streamIDStatements
+	insertInviteEventStmt         *sql.Stmt
+	selectInviteEventsInRangeStmt *sql.Stmt
+	deleteInviteEventStmt         *sql.Stmt
+	selectMaxInviteIDStmt         *sql.Stmt
+}
+
+func NewSqliteInvitesTable(db *sql.DB, streamID *streamIDStatements) (tables.Invites, error) {
+	s := &inviteEventsStatements{
+		db:                 db,
+		streamIDStatements: streamID,
+	}
+	_, err := db.Exec(inviteEventsSchema)
+	if err != nil {
+		return nil, err
+	}
+	if s.insertInviteEventStmt, err = db.Prepare(insertInviteEventSQL); err != nil {
+		return nil, err
+	}
+	if s.selectInviteEventsInRangeStmt, err = db.Prepare(selectInviteEventsInRangeSQL); err != nil {
+		return nil, err
+	}
+	if s.deleteInviteEventStmt, err = db.Prepare(deleteInviteEventSQL); err != nil {
+		return nil, err
+	}
+	if s.selectMaxInviteIDStmt, err = db.Prepare(selectMaxInviteIDSQL); err != nil {
+		return nil, err
+	}
+	return s, nil
+}
+
+func (s *inviteEventsStatements) InsertInviteEvent(
+	ctx context.Context, txn *sql.Tx, inviteEvent *gomatrixserverlib.HeaderedEvent,
+) (streamPos types.StreamPosition, err error) {
+	streamPos, err = s.streamIDStatements.nextInviteID(ctx, txn)
+	if err != nil {
+		return
+	}
+
+	var headeredJSON []byte
+	headeredJSON, err = json.Marshal(inviteEvent)
+	if err != nil {
+		return
+	}
+
+	stmt := sqlutil.TxStmt(txn, s.insertInviteEventStmt)
+	_, err = stmt.ExecContext(
+		ctx,
+		streamPos,
+		inviteEvent.RoomID(),
+		inviteEvent.EventID(),
+		*inviteEvent.StateKey(),
+		headeredJSON,
+	)
+	return
+}
+
+func (s *inviteEventsStatements) DeleteInviteEvent(
+	ctx context.Context, txn *sql.Tx, inviteEventID string,
+) (types.StreamPosition, error) {
+	streamPos, err := s.streamIDStatements.nextInviteID(ctx, txn)
+	if err != nil {
+		return streamPos, err
+	}
+	stmt := sqlutil.TxStmt(txn, s.deleteInviteEventStmt)
+	_, err = stmt.ExecContext(ctx, streamPos, inviteEventID)
+	return streamPos, err
+}
+
+// selectInviteEventsInRange returns a map of room ID to invite event for the
+// active invites for the target user ID in the supplied range.
+func (s *inviteEventsStatements) SelectInviteEventsInRange(
+	ctx context.Context, txn *sql.Tx, targetUserID string, r types.Range,
+) (map[string]*gomatrixserverlib.HeaderedEvent, map[string]*gomatrixserverlib.HeaderedEvent, error) {
+	stmt := sqlutil.TxStmt(txn, s.selectInviteEventsInRangeStmt)
+	rows, err := stmt.QueryContext(ctx, targetUserID, r.Low(), r.High())
+	if err != nil {
+		return nil, nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "selectInviteEventsInRange: rows.close() failed")
+	result := map[string]*gomatrixserverlib.HeaderedEvent{}
+	retired := map[string]*gomatrixserverlib.HeaderedEvent{}
+	for rows.Next() {
+		var (
+			roomID    string
+			eventJSON []byte
+			deleted   bool
+		)
+		if err = rows.Scan(&roomID, &eventJSON, &deleted); err != nil {
+			return nil, nil, err
+		}
+
+		// if we have seen this room before, it has a higher stream position and hence takes priority
+		// because the query is ORDER BY id DESC so drop them
+		_, isRetired := retired[roomID]
+		_, isInvited := result[roomID]
+		if isRetired || isInvited {
+			continue
+		}
+
+		var event *gomatrixserverlib.HeaderedEvent
+		if err := json.Unmarshal(eventJSON, &event); err != nil {
+			return nil, nil, err
+		}
+		if deleted {
+			retired[roomID] = event
+		} else {
+			result[roomID] = event
+		}
+	}
+	return result, retired, nil
+}
+
+func (s *inviteEventsStatements) SelectMaxInviteID(
+	ctx context.Context, txn *sql.Tx,
+) (id int64, err error) {
+	var nullableID sql.NullInt64
+	stmt := sqlutil.TxStmt(txn, s.selectMaxInviteIDStmt)
+	err = stmt.QueryRowContext(ctx).Scan(&nullableID)
+	if nullableID.Valid {
+		id = nullableID.Int64
+	}
+	return
+}

syncapi/storage/cosmosdb/memberships_table.go

@@ -0,0 +1,119 @@
+// Copyright 2021 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+	"strings"
+
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/syncapi/storage/tables"
+	"github.com/matrix-org/dendrite/syncapi/types"
+	"github.com/matrix-org/gomatrixserverlib"
+)
+
+// The memberships table is designed to track the last time that
+// the user was a given state. This allows us to find out the
+// most recent time that a user was invited to, joined or left
+// a room, either by choice or otherwise. This is important for
+// building history visibility.
+
+const membershipsSchema = `
+CREATE TABLE IF NOT EXISTS syncapi_memberships (
+    -- The 'room_id' key for the state event.
+    room_id TEXT NOT NULL,
+    -- The state event ID
+	user_id TEXT NOT NULL,
+	-- The status of the membership
+	membership TEXT NOT NULL,
+	-- The event ID that last changed the membership
+	event_id TEXT NOT NULL,
+	-- The stream position of the change
+	stream_pos BIGINT NOT NULL,
+	-- The topological position of the change in the room
+	topological_pos BIGINT NOT NULL,
+	-- Unique index
+	UNIQUE (room_id, user_id, membership)
+);
+`
+
+const upsertMembershipSQL = "" +
+	"INSERT INTO syncapi_memberships (room_id, user_id, membership, event_id, stream_pos, topological_pos)" +
+	" VALUES ($1, $2, $3, $4, $5, $6)" +
+	" ON CONFLICT (room_id, user_id, membership)" +
+	" DO UPDATE SET event_id = $4, stream_pos = $5, topological_pos = $6"
+
+const selectMembershipSQL = "" +
+	"SELECT event_id, stream_pos, topological_pos FROM syncapi_memberships" +
+	" WHERE room_id = $1 AND user_id = $2 AND membership IN ($3)" +
+	" ORDER BY stream_pos DESC" +
+	" LIMIT 1"
+
+type membershipsStatements struct {
+	db                   *sql.DB
+	upsertMembershipStmt *sql.Stmt
+}
+
+func NewSqliteMembershipsTable(db *sql.DB) (tables.Memberships, error) {
+	s := &membershipsStatements{
+		db: db,
+	}
+	_, err := db.Exec(membershipsSchema)
+	if err != nil {
+		return nil, err
+	}
+	if s.upsertMembershipStmt, err = db.Prepare(upsertMembershipSQL); err != nil {
+		return nil, err
+	}
+	return s, nil
+}
+
+func (s *membershipsStatements) UpsertMembership(
+	ctx context.Context, txn *sql.Tx, event *gomatrixserverlib.HeaderedEvent,
+	streamPos, topologicalPos types.StreamPosition,
+) error {
+	membership, err := event.Membership()
+	if err != nil {
+		return fmt.Errorf("event.Membership: %w", err)
+	}
+	_, err = sqlutil.TxStmt(txn, s.upsertMembershipStmt).ExecContext(
+		ctx,
+		event.RoomID(),
+		*event.StateKey(),
+		membership,
+		event.EventID(),
+		streamPos,
+		topologicalPos,
+	)
+	return err
+}
+
+func (s *membershipsStatements) SelectMembership(
+	ctx context.Context, txn *sql.Tx, roomID, userID, memberships []string,
+) (eventID string, streamPos, topologyPos types.StreamPosition, err error) {
+	params := []interface{}{roomID, userID}
+	for _, membership := range memberships {
+		params = append(params, membership)
+	}
+	orig := strings.Replace(selectMembershipSQL, "($3)", sqlutil.QueryVariadicOffset(len(memberships), 2), 1)
+	stmt, err := s.db.Prepare(orig)
+	if err != nil {
+		return "", 0, 0, err
+	}
+	err = sqlutil.TxStmt(txn, stmt).QueryRowContext(ctx, params...).Scan(&eventID, &streamPos, &topologyPos)
+	return
+}

syncapi/storage/cosmosdb/output_room_events_table.go

@@ -0,0 +1,477 @@
+// Copyright 2017-2018 New Vector Ltd
+// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+	"encoding/json"
+	"fmt"
+	"sort"
+
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/roomserver/api"
+	"github.com/matrix-org/dendrite/syncapi/storage/tables"
+	"github.com/matrix-org/dendrite/syncapi/types"
+
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/gomatrixserverlib"
+	log "github.com/sirupsen/logrus"
+)
+
+const outputRoomEventsSchema = `
+-- Stores output room events received from the roomserver.
+CREATE TABLE IF NOT EXISTS syncapi_output_room_events (
+  id INTEGER PRIMARY KEY AUTOINCREMENT,
+  event_id TEXT NOT NULL UNIQUE,
+  room_id TEXT NOT NULL,
+  headered_event_json TEXT NOT NULL,
+  type TEXT NOT NULL,
+  sender TEXT NOT NULL,
+  contains_url BOOL NOT NULL,
+  add_state_ids TEXT, -- JSON encoded string array
+  remove_state_ids TEXT, -- JSON encoded string array
+  session_id BIGINT,
+  transaction_id TEXT,
+  exclude_from_sync BOOL NOT NULL DEFAULT FALSE
+);
+`
+
+const insertEventSQL = "" +
+	"INSERT INTO syncapi_output_room_events (" +
+	"id, room_id, event_id, headered_event_json, type, sender, contains_url, add_state_ids, remove_state_ids, session_id, transaction_id, exclude_from_sync" +
+	") VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12) " +
+	"ON CONFLICT (event_id) DO UPDATE SET exclude_from_sync = (excluded.exclude_from_sync AND $13)"
+
+const selectEventsSQL = "" +
+	"SELECT event_id, id, headered_event_json, session_id, exclude_from_sync, transaction_id FROM syncapi_output_room_events WHERE event_id = $1"
+
+const selectRecentEventsSQL = "" +
+	"SELECT event_id, id, headered_event_json, session_id, exclude_from_sync, transaction_id FROM syncapi_output_room_events" +
+	" WHERE room_id = $1 AND id > $2 AND id <= $3"
+	// WHEN, ORDER BY and LIMIT are appended by prepareWithFilters
+
+const selectRecentEventsForSyncSQL = "" +
+	"SELECT event_id, id, headered_event_json, session_id, exclude_from_sync, transaction_id FROM syncapi_output_room_events" +
+	" WHERE room_id = $1 AND id > $2 AND id <= $3 AND exclude_from_sync = FALSE"
+	// WHEN, ORDER BY and LIMIT are appended by prepareWithFilters
+
+const selectEarlyEventsSQL = "" +
+	"SELECT event_id, id, headered_event_json, session_id, exclude_from_sync, transaction_id FROM syncapi_output_room_events" +
+	" WHERE room_id = $1 AND id > $2 AND id <= $3"
+	// WHEN, ORDER BY and LIMIT are appended by prepareWithFilters
+
+const selectMaxEventIDSQL = "" +
+	"SELECT MAX(id) FROM syncapi_output_room_events"
+
+const updateEventJSONSQL = "" +
+	"UPDATE syncapi_output_room_events SET headered_event_json=$1 WHERE event_id=$2"
+
+const selectStateInRangeSQL = "" +
+	"SELECT id, headered_event_json, exclude_from_sync, add_state_ids, remove_state_ids" +
+	" FROM syncapi_output_room_events" +
+	" WHERE (id > $1 AND id <= $2)" +
+	" AND ((add_state_ids IS NOT NULL AND add_state_ids != '') OR (remove_state_ids IS NOT NULL AND remove_state_ids != ''))"
+	// WHEN, ORDER BY and LIMIT are appended by prepareWithFilters
+
+const deleteEventsForRoomSQL = "" +
+	"DELETE FROM syncapi_output_room_events WHERE room_id = $1"
+
+type outputRoomEventsStatements struct {
+	db                      *sql.DB
+	streamIDStatements      *streamIDStatements
+	insertEventStmt         *sql.Stmt
+	selectEventsStmt        *sql.Stmt
+	selectMaxEventIDStmt    *sql.Stmt
+	updateEventJSONStmt     *sql.Stmt
+	deleteEventsForRoomStmt *sql.Stmt
+}
+
+func NewSqliteEventsTable(db *sql.DB, streamID *streamIDStatements) (tables.Events, error) {
+	s := &outputRoomEventsStatements{
+		db:                 db,
+		streamIDStatements: streamID,
+	}
+	_, err := db.Exec(outputRoomEventsSchema)
+	if err != nil {
+		return nil, err
+	}
+	if s.insertEventStmt, err = db.Prepare(insertEventSQL); err != nil {
+		return nil, err
+	}
+	if s.selectEventsStmt, err = db.Prepare(selectEventsSQL); err != nil {
+		return nil, err
+	}
+	if s.selectMaxEventIDStmt, err = db.Prepare(selectMaxEventIDSQL); err != nil {
+		return nil, err
+	}
+	if s.updateEventJSONStmt, err = db.Prepare(updateEventJSONSQL); err != nil {
+		return nil, err
+	}
+	if s.deleteEventsForRoomStmt, err = db.Prepare(deleteEventsForRoomSQL); err != nil {
+		return nil, err
+	}
+	return s, nil
+}
+
+func (s *outputRoomEventsStatements) UpdateEventJSON(ctx context.Context, event *gomatrixserverlib.HeaderedEvent) error {
+	headeredJSON, err := json.Marshal(event)
+	if err != nil {
+		return err
+	}
+	_, err = s.updateEventJSONStmt.ExecContext(ctx, headeredJSON, event.EventID())
+	return err
+}
+
+// selectStateInRange returns the state events between the two given PDU stream positions, exclusive of oldPos, inclusive of newPos.
+// Results are bucketed based on the room ID. If the same state is overwritten multiple times between the
+// two positions, only the most recent state is returned.
+func (s *outputRoomEventsStatements) SelectStateInRange(
+	ctx context.Context, txn *sql.Tx, r types.Range,
+	stateFilter *gomatrixserverlib.StateFilter,
+) (map[string]map[string]bool, map[string]types.StreamEvent, error) {
+	stmt, params, err := prepareWithFilters(
+		s.db, txn, selectStateInRangeSQL,
+		[]interface{}{
+			r.Low(), r.High(),
+		},
+		stateFilter.Senders, stateFilter.NotSenders,
+		stateFilter.Types, stateFilter.NotTypes,
+		nil, stateFilter.Limit, FilterOrderAsc,
+	)
+	if err != nil {
+		return nil, nil, fmt.Errorf("s.prepareWithFilters: %w", err)
+	}
+
+	rows, err := stmt.QueryContext(ctx, params...)
+	if err != nil {
+		return nil, nil, err
+	}
+	defer rows.Close() // nolint: errcheck
+	// Fetch all the state change events for all rooms between the two positions then loop each event and:
+	//  - Keep a cache of the event by ID (99% of state change events are for the event itself)
+	//  - For each room ID, build up an array of event IDs which represents cumulative adds/removes
+	// For each room, map cumulative event IDs to events and return. This may need to a batch SELECT based on event ID
+	// if they aren't in the event ID cache. We don't handle state deletion yet.
+	eventIDToEvent := make(map[string]types.StreamEvent)
+
+	// RoomID => A set (map[string]bool) of state event IDs which are between the two positions
+	stateNeeded := make(map[string]map[string]bool)
+
+	for rows.Next() {
+		var (
+			streamPos       types.StreamPosition
+			eventBytes      []byte
+			excludeFromSync bool
+			addIDsJSON      string
+			delIDsJSON      string
+		)
+		if err := rows.Scan(&streamPos, &eventBytes, &excludeFromSync, &addIDsJSON, &delIDsJSON); err != nil {
+			return nil, nil, err
+		}
+
+		addIDs, delIDs, err := unmarshalStateIDs(addIDsJSON, delIDsJSON)
+		if err != nil {
+			return nil, nil, err
+		}
+
+		// Sanity check for deleted state and whine if we see it. We don't need to do anything
+		// since it'll just mark the event as not being needed.
+		if len(addIDs) < len(delIDs) {
+			log.WithFields(log.Fields{
+				"since":   r.From,
+				"current": r.To,
+				"adds":    addIDsJSON,
+				"dels":    delIDsJSON,
+			}).Warn("StateBetween: ignoring deleted state")
+		}
+
+		// TODO: Handle redacted events
+		var ev gomatrixserverlib.HeaderedEvent
+		if err := json.Unmarshal(eventBytes, &ev); err != nil {
+			return nil, nil, err
+		}
+		needSet := stateNeeded[ev.RoomID()]
+		if needSet == nil { // make set if required
+			needSet = make(map[string]bool)
+		}
+		for _, id := range delIDs {
+			needSet[id] = false
+		}
+		for _, id := range addIDs {
+			needSet[id] = true
+		}
+		stateNeeded[ev.RoomID()] = needSet
+
+		eventIDToEvent[ev.EventID()] = types.StreamEvent{
+			HeaderedEvent:   &ev,
+			StreamPosition:  streamPos,
+			ExcludeFromSync: excludeFromSync,
+		}
+	}
+
+	return stateNeeded, eventIDToEvent, nil
+}
+
+// MaxID returns the ID of the last inserted event in this table. 'txn' is optional. If it is not supplied,
+// then this function should only ever be used at startup, as it will race with inserting events if it is
+// done afterwards. If there are no inserted events, 0 is returned.
+func (s *outputRoomEventsStatements) SelectMaxEventID(
+	ctx context.Context, txn *sql.Tx,
+) (id int64, err error) {
+	var nullableID sql.NullInt64
+	stmt := sqlutil.TxStmt(txn, s.selectMaxEventIDStmt)
+	err = stmt.QueryRowContext(ctx).Scan(&nullableID)
+	if nullableID.Valid {
+		id = nullableID.Int64
+	}
+	return
+}
+
+// InsertEvent into the output_room_events table. addState and removeState are an optional list of state event IDs. Returns the position
+// of the inserted event.
+func (s *outputRoomEventsStatements) InsertEvent(
+	ctx context.Context, txn *sql.Tx,
+	event *gomatrixserverlib.HeaderedEvent, addState, removeState []string,
+	transactionID *api.TransactionID, excludeFromSync bool,
+) (types.StreamPosition, error) {
+	var txnID *string
+	var sessionID *int64
+	if transactionID != nil {
+		sessionID = &transactionID.SessionID
+		txnID = &transactionID.TransactionID
+	}
+
+	// Parse content as JSON and search for an "url" key
+	containsURL := false
+	var content map[string]interface{}
+	if json.Unmarshal(event.Content(), &content) != nil {
+		// Set containsURL to true if url is present
+		_, containsURL = content["url"]
+	}
+
+	var headeredJSON []byte
+	headeredJSON, err := json.Marshal(event)
+	if err != nil {
+		return 0, err
+	}
+
+	var addStateJSON, removeStateJSON []byte
+	if len(addState) > 0 {
+		addStateJSON, err = json.Marshal(addState)
+	}
+	if err != nil {
+		return 0, fmt.Errorf("json.Marshal(addState): %w", err)
+	}
+	if len(removeState) > 0 {
+		removeStateJSON, err = json.Marshal(removeState)
+	}
+	if err != nil {
+		return 0, fmt.Errorf("json.Marshal(removeState): %w", err)
+	}
+
+	streamPos, err := s.streamIDStatements.nextPDUID(ctx, txn)
+	if err != nil {
+		return 0, err
+	}
+	insertStmt := sqlutil.TxStmt(txn, s.insertEventStmt)
+	_, err = insertStmt.ExecContext(
+		ctx,
+		streamPos,
+		event.RoomID(),
+		event.EventID(),
+		headeredJSON,
+		event.Type(),
+		event.Sender(),
+		containsURL,
+		string(addStateJSON),
+		string(removeStateJSON),
+		sessionID,
+		txnID,
+		excludeFromSync,
+		excludeFromSync,
+	)
+	return streamPos, err
+}
+
+func (s *outputRoomEventsStatements) SelectRecentEvents(
+	ctx context.Context, txn *sql.Tx,
+	roomID string, r types.Range, eventFilter *gomatrixserverlib.RoomEventFilter,
+	chronologicalOrder bool, onlySyncEvents bool,
+) ([]types.StreamEvent, bool, error) {
+	var query string
+	if onlySyncEvents {
+		query = selectRecentEventsForSyncSQL
+	} else {
+		query = selectRecentEventsSQL
+	}
+
+	stmt, params, err := prepareWithFilters(
+		s.db, txn, query,
+		[]interface{}{
+			roomID, r.Low(), r.High(),
+		},
+		eventFilter.Senders, eventFilter.NotSenders,
+		eventFilter.Types, eventFilter.NotTypes,
+		nil, eventFilter.Limit+1, FilterOrderDesc,
+	)
+	if err != nil {
+		return nil, false, fmt.Errorf("s.prepareWithFilters: %w", err)
+	}
+
+	rows, err := stmt.QueryContext(ctx, params...)
+	if err != nil {
+		return nil, false, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "selectRecentEvents: rows.close() failed")
+	events, err := rowsToStreamEvents(rows)
+	if err != nil {
+		return nil, false, err
+	}
+	if chronologicalOrder {
+		// The events need to be returned from oldest to latest, which isn't
+		// necessary the way the SQL query returns them, so a sort is necessary to
+		// ensure the events are in the right order in the slice.
+		sort.SliceStable(events, func(i int, j int) bool {
+			return events[i].StreamPosition < events[j].StreamPosition
+		})
+	}
+	// we queried for 1 more than the limit, so if we returned one more mark limited=true
+	limited := false
+	if len(events) > eventFilter.Limit {
+		limited = true
+		// re-slice the extra (oldest) event out: in chronological order this is the first entry, else the last.
+		if chronologicalOrder {
+			events = events[1:]
+		} else {
+			events = events[:len(events)-1]
+		}
+	}
+	return events, limited, nil
+}
+
+func (s *outputRoomEventsStatements) SelectEarlyEvents(
+	ctx context.Context, txn *sql.Tx,
+	roomID string, r types.Range, eventFilter *gomatrixserverlib.RoomEventFilter,
+) ([]types.StreamEvent, error) {
+	stmt, params, err := prepareWithFilters(
+		s.db, txn, selectEarlyEventsSQL,
+		[]interface{}{
+			roomID, r.Low(), r.High(),
+		},
+		eventFilter.Senders, eventFilter.NotSenders,
+		eventFilter.Types, eventFilter.NotTypes,
+		nil, eventFilter.Limit, FilterOrderAsc,
+	)
+	if err != nil {
+		return nil, fmt.Errorf("s.prepareWithFilters: %w", err)
+	}
+	rows, err := stmt.QueryContext(ctx, params...)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "selectEarlyEvents: rows.close() failed")
+	events, err := rowsToStreamEvents(rows)
+	if err != nil {
+		return nil, err
+	}
+	// The events need to be returned from oldest to latest, which isn't
+	// necessarily the way the SQL query returns them, so a sort is necessary to
+	// ensure the events are in the right order in the slice.
+	sort.SliceStable(events, func(i int, j int) bool {
+		return events[i].StreamPosition < events[j].StreamPosition
+	})
+	return events, nil
+}
+
+// selectEvents returns the events for the given event IDs. If an event is
+// missing from the database, it will be omitted.
+func (s *outputRoomEventsStatements) SelectEvents(
+	ctx context.Context, txn *sql.Tx, eventIDs []string,
+) ([]types.StreamEvent, error) {
+	var returnEvents []types.StreamEvent
+	stmt := sqlutil.TxStmt(txn, s.selectEventsStmt)
+	for _, eventID := range eventIDs {
+		rows, err := stmt.QueryContext(ctx, eventID)
+		if err != nil {
+			return nil, err
+		}
+		if streamEvents, err := rowsToStreamEvents(rows); err == nil {
+			returnEvents = append(returnEvents, streamEvents...)
+		}
+		internal.CloseAndLogIfError(ctx, rows, "selectEvents: rows.close() failed")
+	}
+	return returnEvents, nil
+}
+
+func (s *outputRoomEventsStatements) DeleteEventsForRoom(
+	ctx context.Context, txn *sql.Tx, roomID string,
+) (err error) {
+	_, err = sqlutil.TxStmt(txn, s.deleteEventsForRoomStmt).ExecContext(ctx, roomID)
+	return err
+}
+
+func rowsToStreamEvents(rows *sql.Rows) ([]types.StreamEvent, error) {
+	var result []types.StreamEvent
+	for rows.Next() {
+		var (
+			eventID         string
+			streamPos       types.StreamPosition
+			eventBytes      []byte
+			excludeFromSync bool
+			sessionID       *int64
+			txnID           *string
+			transactionID   *api.TransactionID
+		)
+		if err := rows.Scan(&eventID, &streamPos, &eventBytes, &sessionID, &excludeFromSync, &txnID); err != nil {
+			return nil, err
+		}
+		// TODO: Handle redacted events
+		var ev gomatrixserverlib.HeaderedEvent
+		if err := ev.UnmarshalJSONWithEventID(eventBytes, eventID); err != nil {
+			return nil, err
+		}
+
+		if sessionID != nil && txnID != nil {
+			transactionID = &api.TransactionID{
+				SessionID:     *sessionID,
+				TransactionID: *txnID,
+			}
+		}
+
+		result = append(result, types.StreamEvent{
+			HeaderedEvent:   &ev,
+			StreamPosition:  streamPos,
+			TransactionID:   transactionID,
+			ExcludeFromSync: excludeFromSync,
+		})
+	}
+	return result, nil
+}
+
+func unmarshalStateIDs(addIDsJSON, delIDsJSON string) (addIDs []string, delIDs []string, err error) {
+	if len(addIDsJSON) > 0 {
+		if err = json.Unmarshal([]byte(addIDsJSON), &addIDs); err != nil {
+			return
+		}
+	}
+	if len(delIDsJSON) > 0 {
+		if err = json.Unmarshal([]byte(delIDsJSON), &delIDs); err != nil {
+			return
+		}
+	}
+	return
+}

syncapi/storage/cosmosdb/output_room_events_topology_table.go

@@ -0,0 +1,179 @@
+// Copyright 2018 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/syncapi/storage/tables"
+	"github.com/matrix-org/dendrite/syncapi/types"
+	"github.com/matrix-org/gomatrixserverlib"
+)
+
+const outputRoomEventsTopologySchema = `
+-- Stores output room events received from the roomserver.
+CREATE TABLE IF NOT EXISTS syncapi_output_room_events_topology (
+  event_id TEXT PRIMARY KEY,
+  topological_position BIGINT NOT NULL,
+  stream_position BIGINT NOT NULL,
+  room_id TEXT NOT NULL,
+
+	UNIQUE(topological_position, room_id, stream_position)
+);
+-- The topological order will be used in events selection and ordering
+-- CREATE UNIQUE INDEX IF NOT EXISTS syncapi_event_topological_position_idx ON syncapi_output_room_events_topology(topological_position, stream_position, room_id);
+`
+
+const insertEventInTopologySQL = "" +
+	"INSERT INTO syncapi_output_room_events_topology (event_id, topological_position, room_id, stream_position)" +
+	" VALUES ($1, $2, $3, $4)" +
+	" ON CONFLICT DO NOTHING"
+
+const selectEventIDsInRangeASCSQL = "" +
+	"SELECT event_id FROM syncapi_output_room_events_topology" +
+	" WHERE room_id = $1 AND (" +
+	"(topological_position > $2 AND topological_position < $3) OR" +
+	"(topological_position = $4 AND stream_position <= $5)" +
+	") ORDER BY topological_position ASC, stream_position ASC LIMIT $6"
+
+const selectEventIDsInRangeDESCSQL = "" +
+	"SELECT event_id  FROM syncapi_output_room_events_topology" +
+	" WHERE room_id = $1 AND (" +
+	"(topological_position > $2 AND topological_position < $3) OR" +
+	"(topological_position = $4 AND stream_position <= $5)" +
+	") ORDER BY topological_position DESC, stream_position DESC LIMIT $6"
+
+const selectPositionInTopologySQL = "" +
+	"SELECT topological_position, stream_position FROM syncapi_output_room_events_topology" +
+	" WHERE event_id = $1"
+
+const selectMaxPositionInTopologySQL = "" +
+	"SELECT MAX(topological_position), stream_position FROM syncapi_output_room_events_topology" +
+	" WHERE room_id = $1 ORDER BY stream_position DESC"
+
+const deleteTopologyForRoomSQL = "" +
+	"DELETE FROM syncapi_output_room_events_topology WHERE room_id = $1"
+
+type outputRoomEventsTopologyStatements struct {
+	db                              *sql.DB
+	insertEventInTopologyStmt       *sql.Stmt
+	selectEventIDsInRangeASCStmt    *sql.Stmt
+	selectEventIDsInRangeDESCStmt   *sql.Stmt
+	selectPositionInTopologyStmt    *sql.Stmt
+	selectMaxPositionInTopologyStmt *sql.Stmt
+	deleteTopologyForRoomStmt       *sql.Stmt
+}
+
+func NewSqliteTopologyTable(db *sql.DB) (tables.Topology, error) {
+	s := &outputRoomEventsTopologyStatements{
+		db: db,
+	}
+	_, err := db.Exec(outputRoomEventsTopologySchema)
+	if err != nil {
+		return nil, err
+	}
+	if s.insertEventInTopologyStmt, err = db.Prepare(insertEventInTopologySQL); err != nil {
+		return nil, err
+	}
+	if s.selectEventIDsInRangeASCStmt, err = db.Prepare(selectEventIDsInRangeASCSQL); err != nil {
+		return nil, err
+	}
+	if s.selectEventIDsInRangeDESCStmt, err = db.Prepare(selectEventIDsInRangeDESCSQL); err != nil {
+		return nil, err
+	}
+	if s.selectPositionInTopologyStmt, err = db.Prepare(selectPositionInTopologySQL); err != nil {
+		return nil, err
+	}
+	if s.selectMaxPositionInTopologyStmt, err = db.Prepare(selectMaxPositionInTopologySQL); err != nil {
+		return nil, err
+	}
+	if s.deleteTopologyForRoomStmt, err = db.Prepare(deleteTopologyForRoomSQL); err != nil {
+		return nil, err
+	}
+	return s, nil
+}
+
+// insertEventInTopology inserts the given event in the room's topology, based
+// on the event's depth.
+func (s *outputRoomEventsTopologyStatements) InsertEventInTopology(
+	ctx context.Context, txn *sql.Tx, event *gomatrixserverlib.HeaderedEvent, pos types.StreamPosition,
+) (types.StreamPosition, error) {
+	_, err := sqlutil.TxStmt(txn, s.insertEventInTopologyStmt).ExecContext(
+		ctx, event.EventID(), event.Depth(), event.RoomID(), pos,
+	)
+	return types.StreamPosition(event.Depth()), err
+}
+
+func (s *outputRoomEventsTopologyStatements) SelectEventIDsInRange(
+	ctx context.Context, txn *sql.Tx, roomID string,
+	minDepth, maxDepth, maxStreamPos types.StreamPosition,
+	limit int, chronologicalOrder bool,
+) (eventIDs []string, err error) {
+	// Decide on the selection's order according to whether chronological order
+	// is requested or not.
+	var stmt *sql.Stmt
+	if chronologicalOrder {
+		stmt = sqlutil.TxStmt(txn, s.selectEventIDsInRangeASCStmt)
+	} else {
+		stmt = sqlutil.TxStmt(txn, s.selectEventIDsInRangeDESCStmt)
+	}
+
+	// Query the event IDs.
+	rows, err := stmt.QueryContext(ctx, roomID, minDepth, maxDepth, maxDepth, maxStreamPos, limit)
+	if err == sql.ErrNoRows {
+		// If no event matched the request, return an empty slice.
+		return []string{}, nil
+	} else if err != nil {
+		return
+	}
+
+	// Return the IDs.
+	var eventID string
+	for rows.Next() {
+		if err = rows.Scan(&eventID); err != nil {
+			return
+		}
+		eventIDs = append(eventIDs, eventID)
+	}
+
+	return
+}
+
+// selectPositionInTopology returns the position of a given event in the
+// topology of the room it belongs to.
+func (s *outputRoomEventsTopologyStatements) SelectPositionInTopology(
+	ctx context.Context, txn *sql.Tx, eventID string,
+) (pos types.StreamPosition, spos types.StreamPosition, err error) {
+	stmt := sqlutil.TxStmt(txn, s.selectPositionInTopologyStmt)
+	err = stmt.QueryRowContext(ctx, eventID).Scan(&pos, &spos)
+	return
+}
+
+func (s *outputRoomEventsTopologyStatements) SelectMaxPositionInTopology(
+	ctx context.Context, txn *sql.Tx, roomID string,
+) (pos types.StreamPosition, spos types.StreamPosition, err error) {
+	stmt := sqlutil.TxStmt(txn, s.selectMaxPositionInTopologyStmt)
+	err = stmt.QueryRowContext(ctx, roomID).Scan(&pos, &spos)
+	return
+}
+
+func (s *outputRoomEventsTopologyStatements) DeleteTopologyForRoom(
+	ctx context.Context, txn *sql.Tx, roomID string,
+) (err error) {
+	_, err = sqlutil.TxStmt(txn, s.deleteTopologyForRoomStmt).ExecContext(ctx, roomID)
+	return err
+}

syncapi/storage/cosmosdb/peeks_table.go

@@ -0,0 +1,206 @@
+// Copyright 2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+	"time"
+
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/syncapi/storage/tables"
+	"github.com/matrix-org/dendrite/syncapi/types"
+)
+
+const peeksSchema = `
+CREATE TABLE IF NOT EXISTS syncapi_peeks (
+	id INTEGER,
+	room_id TEXT NOT NULL,
+	user_id TEXT NOT NULL,
+	device_id TEXT NOT NULL,
+	deleted BOOL NOT NULL DEFAULT false,
+    -- When the peek was created in UNIX epoch ms.
+    creation_ts INTEGER NOT NULL,
+    UNIQUE(room_id, user_id, device_id)
+);
+
+CREATE INDEX IF NOT EXISTS syncapi_peeks_room_id_idx ON syncapi_peeks(room_id);
+CREATE INDEX IF NOT EXISTS syncapi_peeks_user_id_device_id_idx ON syncapi_peeks(user_id, device_id);
+`
+
+const insertPeekSQL = "" +
+	"INSERT OR REPLACE INTO syncapi_peeks" +
+	" (id, room_id, user_id, device_id, creation_ts, deleted)" +
+	" VALUES ($1, $2, $3, $4, $5, false)"
+
+const deletePeekSQL = "" +
+	"UPDATE syncapi_peeks SET deleted=true, id=$1 WHERE room_id = $2 AND user_id = $3 AND device_id = $4"
+
+const deletePeeksSQL = "" +
+	"UPDATE syncapi_peeks SET deleted=true, id=$1 WHERE room_id = $2 AND user_id = $3"
+
+// we care about all the peeks which were created in this range, deleted in this range,
+// or were created before this range but haven't been deleted yet.
+// BEWARE: sqlite chokes on out of order substitution strings.
+const selectPeeksInRangeSQL = "" +
+	"SELECT id, room_id, deleted FROM syncapi_peeks WHERE user_id = $1 AND device_id = $2 AND ((id <= $3 AND NOT deleted=true) OR (id > $3 AND id <= $4))"
+
+const selectPeekingDevicesSQL = "" +
+	"SELECT room_id, user_id, device_id FROM syncapi_peeks WHERE deleted=false"
+
+const selectMaxPeekIDSQL = "" +
+	"SELECT MAX(id) FROM syncapi_peeks"
+
+type peekStatements struct {
+	db                       *sql.DB
+	streamIDStatements       *streamIDStatements
+	insertPeekStmt           *sql.Stmt
+	deletePeekStmt           *sql.Stmt
+	deletePeeksStmt          *sql.Stmt
+	selectPeeksInRangeStmt   *sql.Stmt
+	selectPeekingDevicesStmt *sql.Stmt
+	selectMaxPeekIDStmt      *sql.Stmt
+}
+
+func NewSqlitePeeksTable(db *sql.DB, streamID *streamIDStatements) (tables.Peeks, error) {
+	_, err := db.Exec(peeksSchema)
+	if err != nil {
+		return nil, err
+	}
+	s := &peekStatements{
+		db:                 db,
+		streamIDStatements: streamID,
+	}
+	if s.insertPeekStmt, err = db.Prepare(insertPeekSQL); err != nil {
+		return nil, err
+	}
+	if s.deletePeekStmt, err = db.Prepare(deletePeekSQL); err != nil {
+		return nil, err
+	}
+	if s.deletePeeksStmt, err = db.Prepare(deletePeeksSQL); err != nil {
+		return nil, err
+	}
+	if s.selectPeeksInRangeStmt, err = db.Prepare(selectPeeksInRangeSQL); err != nil {
+		return nil, err
+	}
+	if s.selectPeekingDevicesStmt, err = db.Prepare(selectPeekingDevicesSQL); err != nil {
+		return nil, err
+	}
+	if s.selectMaxPeekIDStmt, err = db.Prepare(selectMaxPeekIDSQL); err != nil {
+		return nil, err
+	}
+	return s, nil
+}
+
+func (s *peekStatements) InsertPeek(
+	ctx context.Context, txn *sql.Tx, roomID, userID, deviceID string,
+) (streamPos types.StreamPosition, err error) {
+	streamPos, err = s.streamIDStatements.nextPDUID(ctx, txn)
+	if err != nil {
+		return
+	}
+	nowMilli := time.Now().UnixNano() / int64(time.Millisecond)
+	_, err = sqlutil.TxStmt(txn, s.insertPeekStmt).ExecContext(ctx, streamPos, roomID, userID, deviceID, nowMilli)
+	return
+}
+
+func (s *peekStatements) DeletePeek(
+	ctx context.Context, txn *sql.Tx, roomID, userID, deviceID string,
+) (streamPos types.StreamPosition, err error) {
+	streamPos, err = s.streamIDStatements.nextPDUID(ctx, txn)
+	if err != nil {
+		return
+	}
+	_, err = sqlutil.TxStmt(txn, s.deletePeekStmt).ExecContext(ctx, streamPos, roomID, userID, deviceID)
+	return
+}
+
+func (s *peekStatements) DeletePeeks(
+	ctx context.Context, txn *sql.Tx, roomID, userID string,
+) (types.StreamPosition, error) {
+	streamPos, err := s.streamIDStatements.nextPDUID(ctx, txn)
+	if err != nil {
+		return 0, err
+	}
+	result, err := sqlutil.TxStmt(txn, s.deletePeeksStmt).ExecContext(ctx, streamPos, roomID, userID)
+	if err != nil {
+		return 0, err
+	}
+	numAffected, err := result.RowsAffected()
+	if err != nil {
+		return 0, err
+	}
+	if numAffected == 0 {
+		return 0, sql.ErrNoRows
+	}
+	return streamPos, nil
+}
+
+func (s *peekStatements) SelectPeeksInRange(
+	ctx context.Context, txn *sql.Tx, userID, deviceID string, r types.Range,
+) (peeks []types.Peek, err error) {
+	rows, err := sqlutil.TxStmt(txn, s.selectPeeksInRangeStmt).QueryContext(ctx, userID, deviceID, r.Low(), r.High())
+	if err != nil {
+		return
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "SelectPeeksInRange: rows.close() failed")
+
+	for rows.Next() {
+		peek := types.Peek{}
+		var id types.StreamPosition
+		if err = rows.Scan(&id, &peek.RoomID, &peek.Deleted); err != nil {
+			return
+		}
+		peek.New = (id > r.Low() && id <= r.High()) && !peek.Deleted
+		peeks = append(peeks, peek)
+	}
+
+	return peeks, rows.Err()
+}
+
+func (s *peekStatements) SelectPeekingDevices(
+	ctx context.Context,
+) (peekingDevices map[string][]types.PeekingDevice, err error) {
+	rows, err := s.selectPeekingDevicesStmt.QueryContext(ctx)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "SelectPeekingDevices: rows.close() failed")
+
+	result := make(map[string][]types.PeekingDevice)
+	for rows.Next() {
+		var roomID, userID, deviceID string
+		if err := rows.Scan(&roomID, &userID, &deviceID); err != nil {
+			return nil, err
+		}
+		devices := result[roomID]
+		devices = append(devices, types.PeekingDevice{UserID: userID, DeviceID: deviceID})
+		result[roomID] = devices
+	}
+	return result, nil
+}
+
+func (s *peekStatements) SelectMaxPeekID(
+	ctx context.Context, txn *sql.Tx,
+) (id int64, err error) {
+	var nullableID sql.NullInt64
+	stmt := sqlutil.TxStmt(txn, s.selectMaxPeekIDStmt)
+	err = stmt.QueryRowContext(ctx).Scan(&nullableID)
+	if nullableID.Valid {
+		id = nullableID.Int64
+	}
+	return
+}

syncapi/storage/cosmosdb/receipt_table.go

@@ -0,0 +1,141 @@
+// Copyright 2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+	"strings"
+
+	"github.com/matrix-org/dendrite/eduserver/api"
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/syncapi/storage/tables"
+	"github.com/matrix-org/dendrite/syncapi/types"
+	"github.com/matrix-org/gomatrixserverlib"
+)
+
+const receiptsSchema = `
+-- Stores data about receipts
+CREATE TABLE IF NOT EXISTS syncapi_receipts (
+	-- The ID
+	id BIGINT,
+	room_id TEXT NOT NULL,
+	receipt_type TEXT NOT NULL,
+	user_id TEXT NOT NULL,
+	event_id TEXT NOT NULL,
+	receipt_ts BIGINT NOT NULL,
+	CONSTRAINT syncapi_receipts_unique UNIQUE (room_id, receipt_type, user_id)
+);
+CREATE INDEX IF NOT EXISTS syncapi_receipts_room_id_idx ON syncapi_receipts(room_id);
+`
+
+const upsertReceipt = "" +
+	"INSERT INTO syncapi_receipts" +
+	" (id, room_id, receipt_type, user_id, event_id, receipt_ts)" +
+	" VALUES ($1, $2, $3, $4, $5, $6)" +
+	" ON CONFLICT (room_id, receipt_type, user_id)" +
+	" DO UPDATE SET id = $7, event_id = $8, receipt_ts = $9"
+
+const selectRoomReceipts = "" +
+	"SELECT id, room_id, receipt_type, user_id, event_id, receipt_ts" +
+	" FROM syncapi_receipts" +
+	" WHERE id > $1 and room_id in ($2)"
+
+const selectMaxReceiptIDSQL = "" +
+	"SELECT MAX(id) FROM syncapi_receipts"
+
+type receiptStatements struct {
+	db                 *sql.DB
+	streamIDStatements *streamIDStatements
+	upsertReceipt      *sql.Stmt
+	selectRoomReceipts *sql.Stmt
+	selectMaxReceiptID *sql.Stmt
+}
+
+func NewSqliteReceiptsTable(db *sql.DB, streamID *streamIDStatements) (tables.Receipts, error) {
+	_, err := db.Exec(receiptsSchema)
+	if err != nil {
+		return nil, err
+	}
+	r := &receiptStatements{
+		db:                 db,
+		streamIDStatements: streamID,
+	}
+	if r.upsertReceipt, err = db.Prepare(upsertReceipt); err != nil {
+		return nil, fmt.Errorf("unable to prepare upsertReceipt statement: %w", err)
+	}
+	if r.selectRoomReceipts, err = db.Prepare(selectRoomReceipts); err != nil {
+		return nil, fmt.Errorf("unable to prepare selectRoomReceipts statement: %w", err)
+	}
+	if r.selectMaxReceiptID, err = db.Prepare(selectMaxReceiptIDSQL); err != nil {
+		return nil, fmt.Errorf("unable to prepare selectRoomReceipts statement: %w", err)
+	}
+	return r, nil
+}
+
+// UpsertReceipt creates new user receipts
+func (r *receiptStatements) UpsertReceipt(ctx context.Context, txn *sql.Tx, roomId, receiptType, userId, eventId string, timestamp gomatrixserverlib.Timestamp) (pos types.StreamPosition, err error) {
+	pos, err = r.streamIDStatements.nextReceiptID(ctx, txn)
+	if err != nil {
+		return
+	}
+	stmt := sqlutil.TxStmt(txn, r.upsertReceipt)
+	_, err = stmt.ExecContext(ctx, pos, roomId, receiptType, userId, eventId, timestamp, pos, eventId, timestamp)
+	return
+}
+
+// SelectRoomReceiptsAfter select all receipts for a given room after a specific timestamp
+func (r *receiptStatements) SelectRoomReceiptsAfter(ctx context.Context, roomIDs []string, streamPos types.StreamPosition) (types.StreamPosition, []api.OutputReceiptEvent, error) {
+	selectSQL := strings.Replace(selectRoomReceipts, "($2)", sqlutil.QueryVariadicOffset(len(roomIDs), 1), 1)
+	lastPos := streamPos
+	params := make([]interface{}, len(roomIDs)+1)
+	params[0] = streamPos
+	for k, v := range roomIDs {
+		params[k+1] = v
+	}
+	rows, err := r.db.QueryContext(ctx, selectSQL, params...)
+	if err != nil {
+		return 0, nil, fmt.Errorf("unable to query room receipts: %w", err)
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "SelectRoomReceiptsAfter: rows.close() failed")
+	var res []api.OutputReceiptEvent
+	for rows.Next() {
+		r := api.OutputReceiptEvent{}
+		var id types.StreamPosition
+		err = rows.Scan(&id, &r.RoomID, &r.Type, &r.UserID, &r.EventID, &r.Timestamp)
+		if err != nil {
+			return 0, res, fmt.Errorf("unable to scan row to api.Receipts: %w", err)
+		}
+		res = append(res, r)
+		if id > lastPos {
+			lastPos = id
+		}
+	}
+	return lastPos, res, rows.Err()
+}
+
+func (s *receiptStatements) SelectMaxReceiptID(
+	ctx context.Context, txn *sql.Tx,
+) (id int64, err error) {
+	var nullableID sql.NullInt64
+	stmt := sqlutil.TxStmt(txn, s.selectMaxReceiptID)
+	err = stmt.QueryRowContext(ctx).Scan(&nullableID)
+	if nullableID.Valid {
+		id = nullableID.Int64
+	}
+	return
+}

syncapi/storage/cosmosdb/send_to_device_table.go

@@ -0,0 +1,160 @@
+// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+	"encoding/json"
+
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/syncapi/storage/tables"
+	"github.com/matrix-org/dendrite/syncapi/types"
+	"github.com/sirupsen/logrus"
+)
+
+const sendToDeviceSchema = `
+-- Stores send-to-device messages.
+CREATE TABLE IF NOT EXISTS syncapi_send_to_device (
+	-- The ID that uniquely identifies this message.
+	id INTEGER PRIMARY KEY AUTOINCREMENT,
+	-- The user ID to send the message to.
+	user_id TEXT NOT NULL,
+	-- The device ID to send the message to.
+	device_id TEXT NOT NULL,
+	-- The event content JSON.
+	content TEXT NOT NULL
+);
+`
+
+const insertSendToDeviceMessageSQL = `
+	INSERT INTO syncapi_send_to_device (user_id, device_id, content)
+	  VALUES ($1, $2, $3)
+`
+
+const selectSendToDeviceMessagesSQL = `
+	SELECT id, user_id, device_id, content
+	  FROM syncapi_send_to_device
+	  WHERE user_id = $1 AND device_id = $2 AND id > $3 AND id <= $4
+	  ORDER BY id DESC
+`
+
+const deleteSendToDeviceMessagesSQL = `
+	DELETE FROM syncapi_send_to_device
+	  WHERE user_id = $1 AND device_id = $2 AND id < $3
+`
+
+const selectMaxSendToDeviceIDSQL = "" +
+	"SELECT MAX(id) FROM syncapi_send_to_device"
+
+type sendToDeviceStatements struct {
+	db                             *sql.DB
+	insertSendToDeviceMessageStmt  *sql.Stmt
+	selectSendToDeviceMessagesStmt *sql.Stmt
+	deleteSendToDeviceMessagesStmt *sql.Stmt
+	selectMaxSendToDeviceIDStmt    *sql.Stmt
+}
+
+func NewSqliteSendToDeviceTable(db *sql.DB) (tables.SendToDevice, error) {
+	s := &sendToDeviceStatements{
+		db: db,
+	}
+	_, err := db.Exec(sendToDeviceSchema)
+	if err != nil {
+		return nil, err
+	}
+	if s.insertSendToDeviceMessageStmt, err = db.Prepare(insertSendToDeviceMessageSQL); err != nil {
+		return nil, err
+	}
+	if s.selectSendToDeviceMessagesStmt, err = db.Prepare(selectSendToDeviceMessagesSQL); err != nil {
+		return nil, err
+	}
+	if s.deleteSendToDeviceMessagesStmt, err = db.Prepare(deleteSendToDeviceMessagesSQL); err != nil {
+		return nil, err
+	}
+	if s.selectMaxSendToDeviceIDStmt, err = db.Prepare(selectMaxSendToDeviceIDSQL); err != nil {
+		return nil, err
+	}
+	return s, nil
+}
+
+func (s *sendToDeviceStatements) InsertSendToDeviceMessage(
+	ctx context.Context, txn *sql.Tx, userID, deviceID, content string,
+) (pos types.StreamPosition, err error) {
+	var result sql.Result
+	result, err = sqlutil.TxStmt(txn, s.insertSendToDeviceMessageStmt).ExecContext(ctx, userID, deviceID, content)
+	if p, err := result.LastInsertId(); err != nil {
+		return 0, err
+	} else {
+		pos = types.StreamPosition(p)
+	}
+	return
+}
+
+func (s *sendToDeviceStatements) SelectSendToDeviceMessages(
+	ctx context.Context, txn *sql.Tx, userID, deviceID string, from, to types.StreamPosition,
+) (lastPos types.StreamPosition, events []types.SendToDeviceEvent, err error) {
+	rows, err := sqlutil.TxStmt(txn, s.selectSendToDeviceMessagesStmt).QueryContext(ctx, userID, deviceID, from, to)
+	if err != nil {
+		return
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "SelectSendToDeviceMessages: rows.close() failed")
+
+	for rows.Next() {
+		var id types.StreamPosition
+		var userID, deviceID, content string
+		if err = rows.Scan(&id, &userID, &deviceID, &content); err != nil {
+			logrus.WithError(err).Errorf("Failed to retrieve send-to-device message")
+			return
+		}
+		if id > lastPos {
+			lastPos = id
+		}
+		event := types.SendToDeviceEvent{
+			ID:       id,
+			UserID:   userID,
+			DeviceID: deviceID,
+		}
+		if err = json.Unmarshal([]byte(content), &event.SendToDeviceEvent); err != nil {
+			logrus.WithError(err).Errorf("Failed to unmarshal send-to-device message")
+			continue
+		}
+		events = append(events, event)
+	}
+	if lastPos == 0 {
+		lastPos = to
+	}
+	return lastPos, events, rows.Err()
+}
+
+func (s *sendToDeviceStatements) DeleteSendToDeviceMessages(
+	ctx context.Context, txn *sql.Tx, userID, deviceID string, pos types.StreamPosition,
+) (err error) {
+	_, err = sqlutil.TxStmt(txn, s.deleteSendToDeviceMessagesStmt).ExecContext(ctx, userID, deviceID, pos)
+	return
+}
+
+func (s *sendToDeviceStatements) SelectMaxSendToDeviceMessageID(
+	ctx context.Context, txn *sql.Tx,
+) (id int64, err error) {
+	var nullableID sql.NullInt64
+	stmt := sqlutil.TxStmt(txn, s.selectMaxSendToDeviceIDStmt)
+	err = stmt.QueryRowContext(ctx).Scan(&nullableID)
+	if nullableID.Valid {
+		id = nullableID.Int64
+	}
+	return
+}

syncapi/storage/cosmosdb/stream_id_table.go

@@ -0,0 +1,94 @@
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/syncapi/types"
+)
+
+const streamIDTableSchema = `
+-- Global stream ID counter, used by other tables.
+CREATE TABLE IF NOT EXISTS syncapi_stream_id (
+  stream_name TEXT NOT NULL PRIMARY KEY,
+  stream_id INT DEFAULT 0,
+
+  UNIQUE(stream_name)
+);
+INSERT INTO syncapi_stream_id (stream_name, stream_id) VALUES ("global", 0)
+  ON CONFLICT DO NOTHING;
+INSERT INTO syncapi_stream_id (stream_name, stream_id) VALUES ("receipt", 0)
+  ON CONFLICT DO NOTHING;
+INSERT INTO syncapi_stream_id (stream_name, stream_id) VALUES ("accountdata", 0)
+  ON CONFLICT DO NOTHING;
+INSERT INTO syncapi_stream_id (stream_name, stream_id) VALUES ("invite", 0)
+  ON CONFLICT DO NOTHING;
+`
+
+const increaseStreamIDStmt = "" +
+	"UPDATE syncapi_stream_id SET stream_id = stream_id + 1 WHERE stream_name = $1"
+
+const selectStreamIDStmt = "" +
+	"SELECT stream_id FROM syncapi_stream_id WHERE stream_name = $1"
+
+type streamIDStatements struct {
+	db                   *sql.DB
+	increaseStreamIDStmt *sql.Stmt
+	selectStreamIDStmt   *sql.Stmt
+}
+
+func (s *streamIDStatements) prepare(db *sql.DB) (err error) {
+	s.db = db
+	_, err = db.Exec(streamIDTableSchema)
+	if err != nil {
+		return
+	}
+	if s.increaseStreamIDStmt, err = db.Prepare(increaseStreamIDStmt); err != nil {
+		return
+	}
+	if s.selectStreamIDStmt, err = db.Prepare(selectStreamIDStmt); err != nil {
+		return
+	}
+	return
+}
+
+func (s *streamIDStatements) nextPDUID(ctx context.Context, txn *sql.Tx) (pos types.StreamPosition, err error) {
+	increaseStmt := sqlutil.TxStmt(txn, s.increaseStreamIDStmt)
+	selectStmt := sqlutil.TxStmt(txn, s.selectStreamIDStmt)
+	if _, err = increaseStmt.ExecContext(ctx, "global"); err != nil {
+		return
+	}
+	err = selectStmt.QueryRowContext(ctx, "global").Scan(&pos)
+	return
+}
+
+func (s *streamIDStatements) nextReceiptID(ctx context.Context, txn *sql.Tx) (pos types.StreamPosition, err error) {
+	increaseStmt := sqlutil.TxStmt(txn, s.increaseStreamIDStmt)
+	selectStmt := sqlutil.TxStmt(txn, s.selectStreamIDStmt)
+	if _, err = increaseStmt.ExecContext(ctx, "receipt"); err != nil {
+		return
+	}
+	err = selectStmt.QueryRowContext(ctx, "receipt").Scan(&pos)
+	return
+}
+
+func (s *streamIDStatements) nextInviteID(ctx context.Context, txn *sql.Tx) (pos types.StreamPosition, err error) {
+	increaseStmt := sqlutil.TxStmt(txn, s.increaseStreamIDStmt)
+	selectStmt := sqlutil.TxStmt(txn, s.selectStreamIDStmt)
+	if _, err = increaseStmt.ExecContext(ctx, "invite"); err != nil {
+		return
+	}
+	err = selectStmt.QueryRowContext(ctx, "invite").Scan(&pos)
+	return
+}
+
+func (s *streamIDStatements) nextAccountDataID(ctx context.Context, txn *sql.Tx) (pos types.StreamPosition, err error) {
+	increaseStmt := sqlutil.TxStmt(txn, s.increaseStreamIDStmt)
+	selectStmt := sqlutil.TxStmt(txn, s.selectStreamIDStmt)
+	if _, err = increaseStmt.ExecContext(ctx, "accountdata"); err != nil {
+		return
+	}
+	err = selectStmt.QueryRowContext(ctx, "accountdata").Scan(&pos)
+	return
+}

syncapi/storage/cosmosdb/syncserver.go

@@ -0,0 +1,128 @@
+// Copyright 2017-2018 New Vector Ltd
+// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"database/sql"
+
+	// Import the sqlite3 package
+	_ "github.com/mattn/go-sqlite3"
+
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/setup/config"
+	"github.com/matrix-org/dendrite/syncapi/storage/shared"
+	"github.com/matrix-org/dendrite/syncapi/storage/sqlite3/deltas"
+)
+
+// SyncServerDatasource represents a sync server datasource which manages
+// both the database for PDUs and caches for EDUs.
+type SyncServerDatasource struct {
+	shared.Database
+	db     *sql.DB
+	writer sqlutil.Writer
+	sqlutil.PartitionOffsetStatements
+	streamID streamIDStatements
+}
+
+// NewDatabase creates a new sync server database
+// nolint: gocyclo
+func NewDatabase(dbProperties *config.DatabaseOptions) (*SyncServerDatasource, error) {
+	var d SyncServerDatasource
+	var err error
+	if d.db, err = sqlutil.Open(dbProperties); err != nil {
+		return nil, err
+	}
+	d.writer = sqlutil.NewExclusiveWriter()
+	if err = d.prepare(dbProperties); err != nil {
+		return nil, err
+	}
+	return &d, nil
+}
+
+func (d *SyncServerDatasource) prepare(dbProperties *config.DatabaseOptions) (err error) {
+	if err = d.PartitionOffsetStatements.Prepare(d.db, d.writer, "syncapi"); err != nil {
+		return err
+	}
+	if err = d.streamID.prepare(d.db); err != nil {
+		return err
+	}
+	accountData, err := NewSqliteAccountDataTable(d.db, &d.streamID)
+	if err != nil {
+		return err
+	}
+	events, err := NewSqliteEventsTable(d.db, &d.streamID)
+	if err != nil {
+		return err
+	}
+	roomState, err := NewSqliteCurrentRoomStateTable(d.db, &d.streamID)
+	if err != nil {
+		return err
+	}
+	invites, err := NewSqliteInvitesTable(d.db, &d.streamID)
+	if err != nil {
+		return err
+	}
+	peeks, err := NewSqlitePeeksTable(d.db, &d.streamID)
+	if err != nil {
+		return err
+	}
+	topology, err := NewSqliteTopologyTable(d.db)
+	if err != nil {
+		return err
+	}
+	bwExtrem, err := NewSqliteBackwardsExtremitiesTable(d.db)
+	if err != nil {
+		return err
+	}
+	sendToDevice, err := NewSqliteSendToDeviceTable(d.db)
+	if err != nil {
+		return err
+	}
+	filter, err := NewSqliteFilterTable(d.db)
+	if err != nil {
+		return err
+	}
+	receipts, err := NewSqliteReceiptsTable(d.db, &d.streamID)
+	if err != nil {
+		return err
+	}
+	memberships, err := NewSqliteMembershipsTable(d.db)
+	if err != nil {
+		return err
+	}
+	m := sqlutil.NewMigrations()
+	deltas.LoadFixSequences(m)
+	deltas.LoadRemoveSendToDeviceSentColumn(m)
+	if err = m.RunDeltas(d.db, dbProperties); err != nil {
+		return err
+	}
+	d.Database = shared.Database{
+		DB:                  d.db,
+		Writer:              d.writer,
+		Invites:             invites,
+		Peeks:               peeks,
+		AccountData:         accountData,
+		OutputEvents:        events,
+		BackwardExtremities: bwExtrem,
+		CurrentRoomState:    roomState,
+		Topology:            topology,
+		Filter:              filter,
+		SendToDevice:        sendToDevice,
+		Receipts:            receipts,
+		Memberships:         memberships,
+	}
+	return nil
+}

syncapi/storage/storage.go

@@ -20,6 +20,7 @@ import (
 	"fmt"
 
 	"github.com/matrix-org/dendrite/setup/config"
+	"github.com/matrix-org/dendrite/syncapi/storage/cosmosdb"
 	"github.com/matrix-org/dendrite/syncapi/storage/postgres"
 	"github.com/matrix-org/dendrite/syncapi/storage/sqlite3"
 )
@@ -27,6 +28,8 @@ import (
 // NewSyncServerDatasource opens a database connection.
 func NewSyncServerDatasource(dbProperties *config.DatabaseOptions) (Database, error) {
 	switch {
+	case dbProperties.ConnectionString.IsCosmosDB():
+		return cosmosdb.NewDatabase(dbProperties)
 	case dbProperties.ConnectionString.IsSQLite():
 		return sqlite3.NewDatabase(dbProperties)
 	case dbProperties.ConnectionString.IsPostgres():

syncapi/storage/storage_wasm.go

@@ -24,6 +24,8 @@ import (
 // NewPublicRoomsServerDatabase opens a database connection.
 func NewSyncServerDatasource(dbProperties *config.DatabaseOptions) (Database, error) {
 	switch {
+	case dbProperties.ConnectionString.IsCosmosDB():
+		return nil, fmt.Errorf("can't use CosmosDB implementation")
 	case dbProperties.ConnectionString.IsSQLite():
 		return sqlite3.NewDatabase(dbProperties)
 	case dbProperties.ConnectionString.IsPostgres():

userapi/storage/accounts/cosmosdb/account_data_table.go

@@ -0,0 +1,134 @@
+// Copyright 2017 Vector Creations Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+	"encoding/json"
+
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+)
+
+const accountDataSchema = `
+-- Stores data about accounts data.
+CREATE TABLE IF NOT EXISTS account_data (
+    -- The Matrix user ID localpart for this account
+    localpart TEXT NOT NULL,
+    -- The room ID for this data (empty string if not specific to a room)
+    room_id TEXT,
+    -- The account data type
+    type TEXT NOT NULL,
+    -- The account data content
+    content TEXT NOT NULL,
+
+    PRIMARY KEY(localpart, room_id, type)
+);
+`
+
+const insertAccountDataSQL = `
+	INSERT INTO account_data(localpart, room_id, type, content) VALUES($1, $2, $3, $4)
+	ON CONFLICT (localpart, room_id, type) DO UPDATE SET content = $4
+`
+
+const selectAccountDataSQL = "" +
+	"SELECT room_id, type, content FROM account_data WHERE localpart = $1"
+
+const selectAccountDataByTypeSQL = "" +
+	"SELECT content FROM account_data WHERE localpart = $1 AND room_id = $2 AND type = $3"
+
+type accountDataStatements struct {
+	db                          *sql.DB
+	insertAccountDataStmt       *sql.Stmt
+	selectAccountDataStmt       *sql.Stmt
+	selectAccountDataByTypeStmt *sql.Stmt
+}
+
+func (s *accountDataStatements) prepare(db *sql.DB) (err error) {
+	s.db = db
+	_, err = db.Exec(accountDataSchema)
+	if err != nil {
+		return
+	}
+	if s.insertAccountDataStmt, err = db.Prepare(insertAccountDataSQL); err != nil {
+		return
+	}
+	if s.selectAccountDataStmt, err = db.Prepare(selectAccountDataSQL); err != nil {
+		return
+	}
+	if s.selectAccountDataByTypeStmt, err = db.Prepare(selectAccountDataByTypeSQL); err != nil {
+		return
+	}
+	return
+}
+
+func (s *accountDataStatements) insertAccountData(
+	ctx context.Context, txn *sql.Tx, localpart, roomID, dataType string, content json.RawMessage,
+) error {
+	_, err := sqlutil.TxStmt(txn, s.insertAccountDataStmt).ExecContext(ctx, localpart, roomID, dataType, content)
+	return err
+}
+
+func (s *accountDataStatements) selectAccountData(
+	ctx context.Context, localpart string,
+) (
+	/* global */ map[string]json.RawMessage,
+	/* rooms */ map[string]map[string]json.RawMessage,
+	error,
+) {
+	rows, err := s.selectAccountDataStmt.QueryContext(ctx, localpart)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	global := map[string]json.RawMessage{}
+	rooms := map[string]map[string]json.RawMessage{}
+
+	for rows.Next() {
+		var roomID string
+		var dataType string
+		var content []byte
+
+		if err = rows.Scan(&roomID, &dataType, &content); err != nil {
+			return nil, nil, err
+		}
+
+		if roomID != "" {
+			if _, ok := rooms[roomID]; !ok {
+				rooms[roomID] = map[string]json.RawMessage{}
+			}
+			rooms[roomID][dataType] = content
+		} else {
+			global[dataType] = content
+		}
+	}
+
+	return global, rooms, nil
+}
+
+func (s *accountDataStatements) selectAccountDataByType(
+	ctx context.Context, localpart, roomID, dataType string,
+) (data json.RawMessage, err error) {
+	var bytes []byte
+	stmt := s.selectAccountDataByTypeStmt
+	if err = stmt.QueryRowContext(ctx, localpart, roomID, dataType).Scan(&bytes); err != nil {
+		if err == sql.ErrNoRows {
+			return nil, nil
+		}
+		return
+	}
+	data = json.RawMessage(bytes)
+	return
+}

userapi/storage/accounts/cosmosdb/accounts_table.go

@@ -0,0 +1,187 @@
+// Copyright 2017 Vector Creations Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+	"time"
+
+	"github.com/matrix-org/dendrite/clientapi/userutil"
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/userapi/api"
+	"github.com/matrix-org/gomatrixserverlib"
+
+	log "github.com/sirupsen/logrus"
+)
+
+const accountsSchema = `
+-- Stores data about accounts.
+CREATE TABLE IF NOT EXISTS account_accounts (
+    -- The Matrix user ID localpart for this account
+    localpart TEXT NOT NULL PRIMARY KEY,
+    -- When this account was first created, as a unix timestamp (ms resolution).
+    created_ts BIGINT NOT NULL,
+    -- The password hash for this account. Can be NULL if this is a passwordless account.
+    password_hash TEXT,
+    -- Identifies which application service this account belongs to, if any.
+    appservice_id TEXT,
+    -- If the account is currently active
+    is_deactivated BOOLEAN DEFAULT 0
+    -- TODO:
+    -- is_guest, is_admin, upgraded_ts, devices, any email reset stuff?
+);
+`
+
+const insertAccountSQL = "" +
+	"INSERT INTO account_accounts(localpart, created_ts, password_hash, appservice_id) VALUES ($1, $2, $3, $4)"
+
+const updatePasswordSQL = "" +
+	"UPDATE account_accounts SET password_hash = $1 WHERE localpart = $2"
+
+const deactivateAccountSQL = "" +
+	"UPDATE account_accounts SET is_deactivated = 1 WHERE localpart = $1"
+
+const selectAccountByLocalpartSQL = "" +
+	"SELECT localpart, appservice_id FROM account_accounts WHERE localpart = $1"
+
+const selectPasswordHashSQL = "" +
+	"SELECT password_hash FROM account_accounts WHERE localpart = $1 AND is_deactivated = 0"
+
+const selectNewNumericLocalpartSQL = "" +
+	"SELECT COUNT(localpart) FROM account_accounts"
+
+type accountsStatements struct {
+	db                            *sql.DB
+	insertAccountStmt             *sql.Stmt
+	updatePasswordStmt            *sql.Stmt
+	deactivateAccountStmt         *sql.Stmt
+	selectAccountByLocalpartStmt  *sql.Stmt
+	selectPasswordHashStmt        *sql.Stmt
+	selectNewNumericLocalpartStmt *sql.Stmt
+	serverName                    gomatrixserverlib.ServerName
+}
+
+func (s *accountsStatements) execSchema(db *sql.DB) error {
+	_, err := db.Exec(accountsSchema)
+	return err
+}
+
+func (s *accountsStatements) prepare(db *sql.DB, server gomatrixserverlib.ServerName) (err error) {
+	s.db = db
+	if s.insertAccountStmt, err = db.Prepare(insertAccountSQL); err != nil {
+		return
+	}
+	if s.updatePasswordStmt, err = db.Prepare(updatePasswordSQL); err != nil {
+		return
+	}
+	if s.deactivateAccountStmt, err = db.Prepare(deactivateAccountSQL); err != nil {
+		return
+	}
+	if s.selectAccountByLocalpartStmt, err = db.Prepare(selectAccountByLocalpartSQL); err != nil {
+		return
+	}
+	if s.selectPasswordHashStmt, err = db.Prepare(selectPasswordHashSQL); err != nil {
+		return
+	}
+	if s.selectNewNumericLocalpartStmt, err = db.Prepare(selectNewNumericLocalpartSQL); err != nil {
+		return
+	}
+	s.serverName = server
+	return
+}
+
+// insertAccount creates a new account. 'hash' should be the password hash for this account. If it is missing,
+// this account will be passwordless. Returns an error if this account already exists. Returns the account
+// on success.
+func (s *accountsStatements) insertAccount(
+	ctx context.Context, txn *sql.Tx, localpart, hash, appserviceID string,
+) (*api.Account, error) {
+	createdTimeMS := time.Now().UnixNano() / 1000000
+	stmt := s.insertAccountStmt
+
+	var err error
+	if appserviceID == "" {
+		_, err = sqlutil.TxStmt(txn, stmt).ExecContext(ctx, localpart, createdTimeMS, hash, nil)
+	} else {
+		_, err = sqlutil.TxStmt(txn, stmt).ExecContext(ctx, localpart, createdTimeMS, hash, appserviceID)
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	return &api.Account{
+		Localpart:    localpart,
+		UserID:       userutil.MakeUserID(localpart, s.serverName),
+		ServerName:   s.serverName,
+		AppServiceID: appserviceID,
+	}, nil
+}
+
+func (s *accountsStatements) updatePassword(
+	ctx context.Context, localpart, passwordHash string,
+) (err error) {
+	_, err = s.updatePasswordStmt.ExecContext(ctx, passwordHash, localpart)
+	return
+}
+
+func (s *accountsStatements) deactivateAccount(
+	ctx context.Context, localpart string,
+) (err error) {
+	_, err = s.deactivateAccountStmt.ExecContext(ctx, localpart)
+	return
+}
+
+func (s *accountsStatements) selectPasswordHash(
+	ctx context.Context, localpart string,
+) (hash string, err error) {
+	err = s.selectPasswordHashStmt.QueryRowContext(ctx, localpart).Scan(&hash)
+	return
+}
+
+func (s *accountsStatements) selectAccountByLocalpart(
+	ctx context.Context, localpart string,
+) (*api.Account, error) {
+	var appserviceIDPtr sql.NullString
+	var acc api.Account
+
+	stmt := s.selectAccountByLocalpartStmt
+	err := stmt.QueryRowContext(ctx, localpart).Scan(&acc.Localpart, &appserviceIDPtr)
+	if err != nil {
+		if err != sql.ErrNoRows {
+			log.WithError(err).Error("Unable to retrieve user from the db")
+		}
+		return nil, err
+	}
+	if appserviceIDPtr.Valid {
+		acc.AppServiceID = appserviceIDPtr.String
+	}
+
+	acc.UserID = userutil.MakeUserID(localpart, s.serverName)
+	acc.ServerName = s.serverName
+
+	return &acc, nil
+}
+
+func (s *accountsStatements) selectNewNumericLocalpart(
+	ctx context.Context, txn *sql.Tx,
+) (id int64, err error) {
+	stmt := s.selectNewNumericLocalpartStmt
+	if txn != nil {
+		stmt = sqlutil.TxStmt(txn, stmt)
+	}
+	err = stmt.QueryRowContext(ctx).Scan(&id)
+	return
+}

userapi/storage/accounts/cosmosdb/constraint_wasm.go

@@ -0,0 +1,21 @@
+// Copyright 2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build wasm
+
+package cosmosdb
+
+func isConstraintError(err error) bool {
+	return false
+}

userapi/storage/accounts/cosmosdb/openid_table.go

@@ -0,0 +1,86 @@
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/userapi/api"
+	"github.com/matrix-org/gomatrixserverlib"
+	log "github.com/sirupsen/logrus"
+)
+
+const openIDTokenSchema = `
+-- Stores data about accounts.
+CREATE TABLE IF NOT EXISTS open_id_tokens (
+	-- The value of the token issued to a user
+	token TEXT NOT NULL PRIMARY KEY,
+    -- The Matrix user ID for this account
+	localpart TEXT NOT NULL,
+	-- When the token expires, as a unix timestamp (ms resolution).
+	token_expires_at_ms BIGINT NOT NULL
+);
+`
+
+const insertTokenSQL = "" +
+	"INSERT INTO open_id_tokens(token, localpart, token_expires_at_ms) VALUES ($1, $2, $3)"
+
+const selectTokenSQL = "" +
+	"SELECT localpart, token_expires_at_ms FROM open_id_tokens WHERE token = $1"
+
+type tokenStatements struct {
+	db              *sql.DB
+	insertTokenStmt *sql.Stmt
+	selectTokenStmt *sql.Stmt
+	serverName      gomatrixserverlib.ServerName
+}
+
+func (s *tokenStatements) prepare(db *sql.DB, server gomatrixserverlib.ServerName) (err error) {
+	s.db = db
+	_, err = db.Exec(openIDTokenSchema)
+	if err != nil {
+		return err
+	}
+	if s.insertTokenStmt, err = db.Prepare(insertTokenSQL); err != nil {
+		return
+	}
+	if s.selectTokenStmt, err = db.Prepare(selectTokenSQL); err != nil {
+		return
+	}
+	s.serverName = server
+	return
+}
+
+// insertToken inserts a new OpenID Connect token to the DB.
+// Returns new token, otherwise returns error if the token already exists.
+func (s *tokenStatements) insertToken(
+	ctx context.Context,
+	txn *sql.Tx,
+	token, localpart string,
+	expiresAtMS int64,
+) (err error) {
+	stmt := sqlutil.TxStmt(txn, s.insertTokenStmt)
+	_, err = stmt.ExecContext(ctx, token, localpart, expiresAtMS)
+	return
+}
+
+// selectOpenIDTokenAtrributes gets the attributes associated with an OpenID token from the DB
+// Returns the existing token's attributes, or err if no token is found
+func (s *tokenStatements) selectOpenIDTokenAtrributes(
+	ctx context.Context,
+	token string,
+) (*api.OpenIDTokenAttributes, error) {
+	var openIDTokenAttrs api.OpenIDTokenAttributes
+	err := s.selectTokenStmt.QueryRowContext(ctx, token).Scan(
+		&openIDTokenAttrs.UserID,
+		&openIDTokenAttrs.ExpiresAtMS,
+	)
+	if err != nil {
+		if err != sql.ErrNoRows {
+			log.WithError(err).Error("Unable to retrieve token from the db")
+		}
+		return nil, err
+	}
+
+	return &openIDTokenAttrs, nil
+}

userapi/storage/accounts/cosmosdb/profile_table.go

@@ -0,0 +1,143 @@
+// Copyright 2017 Vector Creations Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+
+	"github.com/matrix-org/dendrite/clientapi/auth/authtypes"
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+)
+
+const profilesSchema = `
+-- Stores data about accounts profiles.
+CREATE TABLE IF NOT EXISTS account_profiles (
+    -- The Matrix user ID localpart for this account
+    localpart TEXT NOT NULL PRIMARY KEY,
+    -- The display name for this account
+    display_name TEXT,
+    -- The URL of the avatar for this account
+    avatar_url TEXT
+);
+`
+
+const insertProfileSQL = "" +
+	"INSERT INTO account_profiles(localpart, display_name, avatar_url) VALUES ($1, $2, $3)"
+
+const selectProfileByLocalpartSQL = "" +
+	"SELECT localpart, display_name, avatar_url FROM account_profiles WHERE localpart = $1"
+
+const setAvatarURLSQL = "" +
+	"UPDATE account_profiles SET avatar_url = $1 WHERE localpart = $2"
+
+const setDisplayNameSQL = "" +
+	"UPDATE account_profiles SET display_name = $1 WHERE localpart = $2"
+
+const selectProfilesBySearchSQL = "" +
+	"SELECT localpart, display_name, avatar_url FROM account_profiles WHERE localpart LIKE $1 OR display_name LIKE $1 LIMIT $2"
+
+type profilesStatements struct {
+	db                           *sql.DB
+	insertProfileStmt            *sql.Stmt
+	selectProfileByLocalpartStmt *sql.Stmt
+	setAvatarURLStmt             *sql.Stmt
+	setDisplayNameStmt           *sql.Stmt
+	selectProfilesBySearchStmt   *sql.Stmt
+}
+
+func (s *profilesStatements) prepare(db *sql.DB) (err error) {
+	s.db = db
+	_, err = db.Exec(profilesSchema)
+	if err != nil {
+		return
+	}
+	if s.insertProfileStmt, err = db.Prepare(insertProfileSQL); err != nil {
+		return
+	}
+	if s.selectProfileByLocalpartStmt, err = db.Prepare(selectProfileByLocalpartSQL); err != nil {
+		return
+	}
+	if s.setAvatarURLStmt, err = db.Prepare(setAvatarURLSQL); err != nil {
+		return
+	}
+	if s.setDisplayNameStmt, err = db.Prepare(setDisplayNameSQL); err != nil {
+		return
+	}
+	if s.selectProfilesBySearchStmt, err = db.Prepare(selectProfilesBySearchSQL); err != nil {
+		return
+	}
+	return
+}
+
+func (s *profilesStatements) insertProfile(
+	ctx context.Context, txn *sql.Tx, localpart string,
+) error {
+	_, err := sqlutil.TxStmt(txn, s.insertProfileStmt).ExecContext(ctx, localpart, "", "")
+	return err
+}
+
+func (s *profilesStatements) selectProfileByLocalpart(
+	ctx context.Context, localpart string,
+) (*authtypes.Profile, error) {
+	var profile authtypes.Profile
+	err := s.selectProfileByLocalpartStmt.QueryRowContext(ctx, localpart).Scan(
+		&profile.Localpart, &profile.DisplayName, &profile.AvatarURL,
+	)
+	if err != nil {
+		return nil, err
+	}
+	return &profile, nil
+}
+
+func (s *profilesStatements) setAvatarURL(
+	ctx context.Context, txn *sql.Tx, localpart string, avatarURL string,
+) (err error) {
+	stmt := sqlutil.TxStmt(txn, s.setAvatarURLStmt)
+	_, err = stmt.ExecContext(ctx, avatarURL, localpart)
+	return
+}
+
+func (s *profilesStatements) setDisplayName(
+	ctx context.Context, txn *sql.Tx, localpart string, displayName string,
+) (err error) {
+	stmt := sqlutil.TxStmt(txn, s.setDisplayNameStmt)
+	_, err = stmt.ExecContext(ctx, displayName, localpart)
+	return
+}
+
+func (s *profilesStatements) selectProfilesBySearch(
+	ctx context.Context, searchString string, limit int,
+) ([]authtypes.Profile, error) {
+	var profiles []authtypes.Profile
+	// The fmt.Sprintf directive below is building a parameter for the
+	// "LIKE" condition in the SQL query. %% escapes the % char, so the
+	// statement in the end will look like "LIKE %searchString%".
+	rows, err := s.selectProfilesBySearchStmt.QueryContext(ctx, fmt.Sprintf("%%%s%%", searchString), limit)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "selectProfilesBySearch: rows.close() failed")
+	for rows.Next() {
+		var profile authtypes.Profile
+		if err := rows.Scan(&profile.Localpart, &profile.DisplayName, &profile.AvatarURL); err != nil {
+			return nil, err
+		}
+		profiles = append(profiles, profile)
+	}
+	return profiles, nil
+}

userapi/storage/accounts/cosmosdb/storage.go

@@ -0,0 +1,408 @@
+// Copyright 2017 Vector Creations Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+	"encoding/json"
+	"errors"
+	"strconv"
+	"sync"
+	"time"
+
+	"github.com/matrix-org/dendrite/clientapi/auth/authtypes"
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/setup/config"
+	"github.com/matrix-org/dendrite/userapi/api"
+	"github.com/matrix-org/dendrite/userapi/storage/accounts/sqlite3/deltas"
+	"github.com/matrix-org/gomatrixserverlib"
+	"golang.org/x/crypto/bcrypt"
+)
+
+// Database represents an account database
+type Database struct {
+	db     *sql.DB
+	writer sqlutil.Writer
+
+	sqlutil.PartitionOffsetStatements
+	accounts              accountsStatements
+	profiles              profilesStatements
+	accountDatas          accountDataStatements
+	threepids             threepidStatements
+	openIDTokens          tokenStatements
+	serverName            gomatrixserverlib.ServerName
+	bcryptCost            int
+	openIDTokenLifetimeMS int64
+
+	accountsMu     sync.Mutex
+	profilesMu     sync.Mutex
+	accountDatasMu sync.Mutex
+	threepidsMu    sync.Mutex
+}
+
+// NewDatabase creates a new accounts and profiles database
+func NewDatabase(dbProperties *config.DatabaseOptions, serverName gomatrixserverlib.ServerName, bcryptCost int, openIDTokenLifetimeMS int64) (*Database, error) {
+	db, err := sqlutil.Open(dbProperties)
+	if err != nil {
+		return nil, err
+	}
+	d := &Database{
+		serverName:            serverName,
+		db:                    db,
+		writer:                sqlutil.NewExclusiveWriter(),
+		bcryptCost:            bcryptCost,
+		openIDTokenLifetimeMS: openIDTokenLifetimeMS,
+	}
+
+	// Create tables before executing migrations so we don't fail if the table is missing,
+	// and THEN prepare statements so we don't fail due to referencing new columns
+	if err = d.accounts.execSchema(db); err != nil {
+		return nil, err
+	}
+	m := sqlutil.NewMigrations()
+	deltas.LoadIsActive(m)
+	if err = m.RunDeltas(db, dbProperties); err != nil {
+		return nil, err
+	}
+
+	partitions := sqlutil.PartitionOffsetStatements{}
+	if err = partitions.Prepare(db, d.writer, "account"); err != nil {
+		return nil, err
+	}
+	if err = d.accounts.prepare(db, serverName); err != nil {
+		return nil, err
+	}
+	if err = d.profiles.prepare(db); err != nil {
+		return nil, err
+	}
+	if err = d.accountDatas.prepare(db); err != nil {
+		return nil, err
+	}
+	if err = d.threepids.prepare(db); err != nil {
+		return nil, err
+	}
+	if err = d.openIDTokens.prepare(db, serverName); err != nil {
+		return nil, err
+	}
+
+	return d, nil
+}
+
+// GetAccountByPassword returns the account associated with the given localpart and password.
+// Returns sql.ErrNoRows if no account exists which matches the given localpart.
+func (d *Database) GetAccountByPassword(
+	ctx context.Context, localpart, plaintextPassword string,
+) (*api.Account, error) {
+	hash, err := d.accounts.selectPasswordHash(ctx, localpart)
+	if err != nil {
+		return nil, err
+	}
+	if err := bcrypt.CompareHashAndPassword([]byte(hash), []byte(plaintextPassword)); err != nil {
+		return nil, err
+	}
+	return d.accounts.selectAccountByLocalpart(ctx, localpart)
+}
+
+// GetProfileByLocalpart returns the profile associated with the given localpart.
+// Returns sql.ErrNoRows if no profile exists which matches the given localpart.
+func (d *Database) GetProfileByLocalpart(
+	ctx context.Context, localpart string,
+) (*authtypes.Profile, error) {
+	return d.profiles.selectProfileByLocalpart(ctx, localpart)
+}
+
+// SetAvatarURL updates the avatar URL of the profile associated with the given
+// localpart. Returns an error if something went wrong with the SQL query
+func (d *Database) SetAvatarURL(
+	ctx context.Context, localpart string, avatarURL string,
+) error {
+	d.profilesMu.Lock()
+	defer d.profilesMu.Unlock()
+	return d.writer.Do(d.db, nil, func(txn *sql.Tx) error {
+		return d.profiles.setAvatarURL(ctx, txn, localpart, avatarURL)
+	})
+}
+
+// SetDisplayName updates the display name of the profile associated with the given
+// localpart. Returns an error if something went wrong with the SQL query
+func (d *Database) SetDisplayName(
+	ctx context.Context, localpart string, displayName string,
+) error {
+	d.profilesMu.Lock()
+	defer d.profilesMu.Unlock()
+	return d.writer.Do(d.db, nil, func(txn *sql.Tx) error {
+		return d.profiles.setDisplayName(ctx, txn, localpart, displayName)
+	})
+}
+
+// SetPassword sets the account password to the given hash.
+func (d *Database) SetPassword(
+	ctx context.Context, localpart, plaintextPassword string,
+) error {
+	hash, err := d.hashPassword(plaintextPassword)
+	if err != nil {
+		return err
+	}
+	err = d.accounts.updatePassword(ctx, localpart, hash)
+	return err
+}
+
+// CreateGuestAccount makes a new guest account and creates an empty profile
+// for this account.
+func (d *Database) CreateGuestAccount(ctx context.Context) (acc *api.Account, err error) {
+	// We need to lock so we sequentially create numeric localparts. If we don't, two calls to
+	// this function will cause the same number to be selected and one will fail with 'database is locked'
+	// when the first txn upgrades to a write txn. We also need to lock the account creation else we can
+	// race with CreateAccount
+	// We know we'll be the only process since this is sqlite ;) so a lock here will be all that is needed.
+	d.profilesMu.Lock()
+	d.accountDatasMu.Lock()
+	d.accountsMu.Lock()
+	defer d.profilesMu.Unlock()
+	defer d.accountDatasMu.Unlock()
+	defer d.accountsMu.Unlock()
+	err = d.writer.Do(d.db, nil, func(txn *sql.Tx) error {
+		var numLocalpart int64
+		numLocalpart, err = d.accounts.selectNewNumericLocalpart(ctx, txn)
+		if err != nil {
+			return err
+		}
+		localpart := strconv.FormatInt(numLocalpart, 10)
+		acc, err = d.createAccount(ctx, txn, localpart, "", "")
+		return err
+	})
+	return acc, err
+}
+
+// CreateAccount makes a new account with the given login name and password, and creates an empty profile
+// for this account. If no password is supplied, the account will be a passwordless account. If the
+// account already exists, it will return nil, ErrUserExists.
+func (d *Database) CreateAccount(
+	ctx context.Context, localpart, plaintextPassword, appserviceID string,
+) (acc *api.Account, err error) {
+	// Create one account at a time else we can get 'database is locked'.
+	d.profilesMu.Lock()
+	d.accountDatasMu.Lock()
+	d.accountsMu.Lock()
+	defer d.profilesMu.Unlock()
+	defer d.accountDatasMu.Unlock()
+	defer d.accountsMu.Unlock()
+	err = d.writer.Do(d.db, nil, func(txn *sql.Tx) error {
+		acc, err = d.createAccount(ctx, txn, localpart, plaintextPassword, appserviceID)
+		return err
+	})
+	return
+}
+
+// WARNING! This function assumes that the relevant mutexes have already
+// been taken out by the caller (e.g. CreateAccount or CreateGuestAccount).
+func (d *Database) createAccount(
+	ctx context.Context, txn *sql.Tx, localpart, plaintextPassword, appserviceID string,
+) (*api.Account, error) {
+	var err error
+	var account *api.Account
+	// Generate a password hash if this is not a password-less user
+	hash := ""
+	if plaintextPassword != "" {
+		hash, err = d.hashPassword(plaintextPassword)
+		if err != nil {
+			return nil, err
+		}
+	}
+	if account, err = d.accounts.insertAccount(ctx, txn, localpart, hash, appserviceID); err != nil {
+		return nil, sqlutil.ErrUserExists
+	}
+	if err = d.profiles.insertProfile(ctx, txn, localpart); err != nil {
+		return nil, err
+	}
+	if err = d.accountDatas.insertAccountData(ctx, txn, localpart, "", "m.push_rules", json.RawMessage(`{
+		"global": {
+			"content": [],
+			"override": [],
+			"room": [],
+			"sender": [],
+			"underride": []
+		}
+	}`)); err != nil {
+		return nil, err
+	}
+	return account, nil
+}
+
+// SaveAccountData saves new account data for a given user and a given room.
+// If the account data is not specific to a room, the room ID should be an empty string
+// If an account data already exists for a given set (user, room, data type), it will
+// update the corresponding row with the new content
+// Returns a SQL error if there was an issue with the insertion/update
+func (d *Database) SaveAccountData(
+	ctx context.Context, localpart, roomID, dataType string, content json.RawMessage,
+) error {
+	d.accountDatasMu.Lock()
+	defer d.accountDatasMu.Unlock()
+	return d.writer.Do(d.db, nil, func(txn *sql.Tx) error {
+		return d.accountDatas.insertAccountData(ctx, txn, localpart, roomID, dataType, content)
+	})
+}
+
+// GetAccountData returns account data related to a given localpart
+// If no account data could be found, returns an empty arrays
+// Returns an error if there was an issue with the retrieval
+func (d *Database) GetAccountData(ctx context.Context, localpart string) (
+	global map[string]json.RawMessage,
+	rooms map[string]map[string]json.RawMessage,
+	err error,
+) {
+	return d.accountDatas.selectAccountData(ctx, localpart)
+}
+
+// GetAccountDataByType returns account data matching a given
+// localpart, room ID and type.
+// If no account data could be found, returns nil
+// Returns an error if there was an issue with the retrieval
+func (d *Database) GetAccountDataByType(
+	ctx context.Context, localpart, roomID, dataType string,
+) (data json.RawMessage, err error) {
+	return d.accountDatas.selectAccountDataByType(
+		ctx, localpart, roomID, dataType,
+	)
+}
+
+// GetNewNumericLocalpart generates and returns a new unused numeric localpart
+func (d *Database) GetNewNumericLocalpart(
+	ctx context.Context,
+) (int64, error) {
+	return d.accounts.selectNewNumericLocalpart(ctx, nil)
+}
+
+func (d *Database) hashPassword(plaintext string) (hash string, err error) {
+	hashBytes, err := bcrypt.GenerateFromPassword([]byte(plaintext), d.bcryptCost)
+	return string(hashBytes), err
+}
+
+// Err3PIDInUse is the error returned when trying to save an association involving
+// a third-party identifier which is already associated to a local user.
+var Err3PIDInUse = errors.New("This third-party identifier is already in use")
+
+// SaveThreePIDAssociation saves the association between a third party identifier
+// and a local Matrix user (identified by the user's ID's local part).
+// If the third-party identifier is already part of an association, returns Err3PIDInUse.
+// Returns an error if there was a problem talking to the database.
+func (d *Database) SaveThreePIDAssociation(
+	ctx context.Context, threepid, localpart, medium string,
+) (err error) {
+	d.threepidsMu.Lock()
+	defer d.threepidsMu.Unlock()
+	return d.writer.Do(d.db, nil, func(txn *sql.Tx) error {
+		user, err := d.threepids.selectLocalpartForThreePID(
+			ctx, txn, threepid, medium,
+		)
+		if err != nil {
+			return err
+		}
+
+		if len(user) > 0 {
+			return Err3PIDInUse
+		}
+
+		return d.threepids.insertThreePID(ctx, txn, threepid, medium, localpart)
+	})
+}
+
+// RemoveThreePIDAssociation removes the association involving a given third-party
+// identifier.
+// If no association exists involving this third-party identifier, returns nothing.
+// If there was a problem talking to the database, returns an error.
+func (d *Database) RemoveThreePIDAssociation(
+	ctx context.Context, threepid string, medium string,
+) (err error) {
+	d.threepidsMu.Lock()
+	defer d.threepidsMu.Unlock()
+	return d.writer.Do(d.db, nil, func(txn *sql.Tx) error {
+		return d.threepids.deleteThreePID(ctx, txn, threepid, medium)
+	})
+}
+
+// GetLocalpartForThreePID looks up the localpart associated with a given third-party
+// identifier.
+// If no association involves the given third-party idenfitier, returns an empty
+// string.
+// Returns an error if there was a problem talking to the database.
+func (d *Database) GetLocalpartForThreePID(
+	ctx context.Context, threepid string, medium string,
+) (localpart string, err error) {
+	return d.threepids.selectLocalpartForThreePID(ctx, nil, threepid, medium)
+}
+
+// GetThreePIDsForLocalpart looks up the third-party identifiers associated with
+// a given local user.
+// If no association is known for this user, returns an empty slice.
+// Returns an error if there was an issue talking to the database.
+func (d *Database) GetThreePIDsForLocalpart(
+	ctx context.Context, localpart string,
+) (threepids []authtypes.ThreePID, err error) {
+	return d.threepids.selectThreePIDsForLocalpart(ctx, localpart)
+}
+
+// CheckAccountAvailability checks if the username/localpart is already present
+// in the database.
+// If the DB returns sql.ErrNoRows the Localpart isn't taken.
+func (d *Database) CheckAccountAvailability(ctx context.Context, localpart string) (bool, error) {
+	_, err := d.accounts.selectAccountByLocalpart(ctx, localpart)
+	if err == sql.ErrNoRows {
+		return true, nil
+	}
+	return false, err
+}
+
+// GetAccountByLocalpart returns the account associated with the given localpart.
+// This function assumes the request is authenticated or the account data is used only internally.
+// Returns sql.ErrNoRows if no account exists which matches the given localpart.
+func (d *Database) GetAccountByLocalpart(ctx context.Context, localpart string,
+) (*api.Account, error) {
+	return d.accounts.selectAccountByLocalpart(ctx, localpart)
+}
+
+// SearchProfiles returns all profiles where the provided localpart or display name
+// match any part of the profiles in the database.
+func (d *Database) SearchProfiles(ctx context.Context, searchString string, limit int,
+) ([]authtypes.Profile, error) {
+	return d.profiles.selectProfilesBySearch(ctx, searchString, limit)
+}
+
+// DeactivateAccount deactivates the user's account, removing all ability for the user to login again.
+func (d *Database) DeactivateAccount(ctx context.Context, localpart string) (err error) {
+	return d.accounts.deactivateAccount(ctx, localpart)
+}
+
+// CreateOpenIDToken persists a new token that was issued for OpenID Connect
+func (d *Database) CreateOpenIDToken(
+	ctx context.Context,
+	token, localpart string,
+) (int64, error) {
+	expiresAtMS := time.Now().UnixNano()/int64(time.Millisecond) + d.openIDTokenLifetimeMS
+	err := d.writer.Do(d.db, nil, func(txn *sql.Tx) error {
+		return d.openIDTokens.insertToken(ctx, txn, token, localpart, expiresAtMS)
+	})
+	return expiresAtMS, err
+}
+
+// GetOpenIDTokenAttributes gets the attributes of issued an OIDC auth token
+func (d *Database) GetOpenIDTokenAttributes(
+	ctx context.Context,
+	token string,
+) (*api.OpenIDTokenAttributes, error) {
+	return d.openIDTokens.selectOpenIDTokenAtrributes(ctx, token)
+}

userapi/storage/accounts/cosmosdb/threepid_table.go

@@ -0,0 +1,133 @@
+// Copyright 2017 Vector Creations Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+
+	"github.com/matrix-org/dendrite/clientapi/auth/authtypes"
+)
+
+const threepidSchema = `
+-- Stores data about third party identifiers
+CREATE TABLE IF NOT EXISTS account_threepid (
+	-- The third party identifier
+	threepid TEXT NOT NULL,
+	-- The 3PID medium
+	medium TEXT NOT NULL DEFAULT 'email',
+	-- The localpart of the Matrix user ID associated to this 3PID
+	localpart TEXT NOT NULL,
+
+	PRIMARY KEY(threepid, medium)
+);
+
+CREATE INDEX IF NOT EXISTS account_threepid_localpart ON account_threepid(localpart);
+`
+
+const selectLocalpartForThreePIDSQL = "" +
+	"SELECT localpart FROM account_threepid WHERE threepid = $1 AND medium = $2"
+
+const selectThreePIDsForLocalpartSQL = "" +
+	"SELECT threepid, medium FROM account_threepid WHERE localpart = $1"
+
+const insertThreePIDSQL = "" +
+	"INSERT INTO account_threepid (threepid, medium, localpart) VALUES ($1, $2, $3)"
+
+const deleteThreePIDSQL = "" +
+	"DELETE FROM account_threepid WHERE threepid = $1 AND medium = $2"
+
+type threepidStatements struct {
+	db                              *sql.DB
+	selectLocalpartForThreePIDStmt  *sql.Stmt
+	selectThreePIDsForLocalpartStmt *sql.Stmt
+	insertThreePIDStmt              *sql.Stmt
+	deleteThreePIDStmt              *sql.Stmt
+}
+
+func (s *threepidStatements) prepare(db *sql.DB) (err error) {
+	s.db = db
+	_, err = db.Exec(threepidSchema)
+	if err != nil {
+		return
+	}
+	if s.selectLocalpartForThreePIDStmt, err = db.Prepare(selectLocalpartForThreePIDSQL); err != nil {
+		return
+	}
+	if s.selectThreePIDsForLocalpartStmt, err = db.Prepare(selectThreePIDsForLocalpartSQL); err != nil {
+		return
+	}
+	if s.insertThreePIDStmt, err = db.Prepare(insertThreePIDSQL); err != nil {
+		return
+	}
+	if s.deleteThreePIDStmt, err = db.Prepare(deleteThreePIDSQL); err != nil {
+		return
+	}
+
+	return
+}
+
+func (s *threepidStatements) selectLocalpartForThreePID(
+	ctx context.Context, txn *sql.Tx, threepid string, medium string,
+) (localpart string, err error) {
+	stmt := sqlutil.TxStmt(txn, s.selectLocalpartForThreePIDStmt)
+	err = stmt.QueryRowContext(ctx, threepid, medium).Scan(&localpart)
+	if err == sql.ErrNoRows {
+		return "", nil
+	}
+	return
+}
+
+func (s *threepidStatements) selectThreePIDsForLocalpart(
+	ctx context.Context, localpart string,
+) (threepids []authtypes.ThreePID, err error) {
+	rows, err := s.selectThreePIDsForLocalpartStmt.QueryContext(ctx, localpart)
+	if err != nil {
+		return
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "selectThreePIDsForLocalpart: rows.close() failed")
+
+	threepids = []authtypes.ThreePID{}
+	for rows.Next() {
+		var threepid string
+		var medium string
+		if err = rows.Scan(&threepid, &medium); err != nil {
+			return
+		}
+		threepids = append(threepids, authtypes.ThreePID{
+			Address: threepid,
+			Medium:  medium,
+		})
+	}
+	return threepids, rows.Err()
+}
+
+func (s *threepidStatements) insertThreePID(
+	ctx context.Context, txn *sql.Tx, threepid, medium, localpart string,
+) (err error) {
+	stmt := sqlutil.TxStmt(txn, s.insertThreePIDStmt)
+	_, err = stmt.ExecContext(ctx, threepid, medium, localpart)
+	return err
+}
+
+func (s *threepidStatements) deleteThreePID(
+	ctx context.Context, txn *sql.Tx, threepid string, medium string) (err error) {
+	stmt := sqlutil.TxStmt(txn, s.deleteThreePIDStmt)
+	_, err = stmt.ExecContext(ctx, threepid, medium)
+	return err
+}

userapi/storage/accounts/storage.go

@@ -20,6 +20,7 @@ import (
 	"fmt"
 
 	"github.com/matrix-org/dendrite/setup/config"
+	"github.com/matrix-org/dendrite/userapi/storage/accounts/cosmosdb"
 	"github.com/matrix-org/dendrite/userapi/storage/accounts/postgres"
 	"github.com/matrix-org/dendrite/userapi/storage/accounts/sqlite3"
 	"github.com/matrix-org/gomatrixserverlib"
@@ -29,6 +30,8 @@ import (
 // and sets postgres connection parameters
 func NewDatabase(dbProperties *config.DatabaseOptions, serverName gomatrixserverlib.ServerName, bcryptCost int, openIDTokenLifetimeMS int64) (Database, error) {
 	switch {
+	case dbProperties.ConnectionString.IsCosmosDB():
+		return cosmosdb.NewDatabase(dbProperties, serverName, bcryptCost, openIDTokenLifetimeMS)
 	case dbProperties.ConnectionString.IsSQLite():
 		return sqlite3.NewDatabase(dbProperties, serverName, bcryptCost, openIDTokenLifetimeMS)
 	case dbProperties.ConnectionString.IsPostgres():

userapi/storage/accounts/storage_wasm.go

@@ -29,6 +29,8 @@ func NewDatabase(
 	openIDTokenLifetimeMS int64,
 ) (Database, error) {
 	switch {
+	case dbProperties.ConnectionString.IsCosmosDB():
+		return nil, fmt.Errorf("can't use CosmosDB implementation")
 	case dbProperties.ConnectionString.IsSQLite():
 		return sqlite3.NewDatabase(dbProperties, serverName, bcryptCost, openIDTokenLifetimeMS)
 	case dbProperties.ConnectionString.IsPostgres():

userapi/storage/devices/cosmosdb/devices_table.go

@@ -0,0 +1,322 @@
+// Copyright 2017 Vector Creations Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"database/sql"
+	"strings"
+	"time"
+
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/userapi/api"
+
+	"github.com/matrix-org/dendrite/clientapi/userutil"
+	"github.com/matrix-org/gomatrixserverlib"
+)
+
+const devicesSchema = `
+-- This sequence is used for automatic allocation of session_id.
+-- CREATE SEQUENCE IF NOT EXISTS device_session_id_seq START 1;
+
+-- Stores data about devices.
+CREATE TABLE IF NOT EXISTS device_devices (
+    access_token TEXT PRIMARY KEY,
+    session_id INTEGER,
+    device_id TEXT ,
+    localpart TEXT ,
+    created_ts BIGINT,
+    display_name TEXT,
+    last_seen_ts BIGINT,
+    ip TEXT,
+    user_agent TEXT,
+
+		UNIQUE (localpart, device_id)
+);
+`
+
+const insertDeviceSQL = "" +
+	"INSERT INTO device_devices (device_id, localpart, access_token, created_ts, display_name, session_id, last_seen_ts, ip, user_agent)" +
+	" VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9)"
+
+const selectDevicesCountSQL = "" +
+	"SELECT COUNT(access_token) FROM device_devices"
+
+const selectDeviceByTokenSQL = "" +
+	"SELECT session_id, device_id, localpart FROM device_devices WHERE access_token = $1"
+
+const selectDeviceByIDSQL = "" +
+	"SELECT display_name FROM device_devices WHERE localpart = $1 and device_id = $2"
+
+const selectDevicesByLocalpartSQL = "" +
+	"SELECT device_id, display_name, last_seen_ts, ip, user_agent FROM device_devices WHERE localpart = $1 AND device_id != $2"
+
+const updateDeviceNameSQL = "" +
+	"UPDATE device_devices SET display_name = $1 WHERE localpart = $2 AND device_id = $3"
+
+const deleteDeviceSQL = "" +
+	"DELETE FROM device_devices WHERE device_id = $1 AND localpart = $2"
+
+const deleteDevicesByLocalpartSQL = "" +
+	"DELETE FROM device_devices WHERE localpart = $1 AND device_id != $2"
+
+const deleteDevicesSQL = "" +
+	"DELETE FROM device_devices WHERE localpart = $1 AND device_id IN ($2)"
+
+const selectDevicesByIDSQL = "" +
+	"SELECT device_id, localpart, display_name FROM device_devices WHERE device_id IN ($1)"
+
+const updateDeviceLastSeen = "" +
+	"UPDATE device_devices SET last_seen_ts = $1, ip = $2 WHERE localpart = $3 AND device_id = $4"
+
+type devicesStatements struct {
+	db                           *sql.DB
+	writer                       sqlutil.Writer
+	insertDeviceStmt             *sql.Stmt
+	selectDevicesCountStmt       *sql.Stmt
+	selectDeviceByTokenStmt      *sql.Stmt
+	selectDeviceByIDStmt         *sql.Stmt
+	selectDevicesByIDStmt        *sql.Stmt
+	selectDevicesByLocalpartStmt *sql.Stmt
+	updateDeviceNameStmt         *sql.Stmt
+	updateDeviceLastSeenStmt     *sql.Stmt
+	deleteDeviceStmt             *sql.Stmt
+	deleteDevicesByLocalpartStmt *sql.Stmt
+	serverName                   gomatrixserverlib.ServerName
+}
+
+func (s *devicesStatements) execSchema(db *sql.DB) error {
+	_, err := db.Exec(devicesSchema)
+	return err
+}
+
+func (s *devicesStatements) prepare(db *sql.DB, writer sqlutil.Writer, server gomatrixserverlib.ServerName) (err error) {
+	s.db = db
+	s.writer = writer
+	if s.insertDeviceStmt, err = db.Prepare(insertDeviceSQL); err != nil {
+		return
+	}
+	if s.selectDevicesCountStmt, err = db.Prepare(selectDevicesCountSQL); err != nil {
+		return
+	}
+	if s.selectDeviceByTokenStmt, err = db.Prepare(selectDeviceByTokenSQL); err != nil {
+		return
+	}
+	if s.selectDeviceByIDStmt, err = db.Prepare(selectDeviceByIDSQL); err != nil {
+		return
+	}
+	if s.selectDevicesByLocalpartStmt, err = db.Prepare(selectDevicesByLocalpartSQL); err != nil {
+		return
+	}
+	if s.updateDeviceNameStmt, err = db.Prepare(updateDeviceNameSQL); err != nil {
+		return
+	}
+	if s.deleteDeviceStmt, err = db.Prepare(deleteDeviceSQL); err != nil {
+		return
+	}
+	if s.deleteDevicesByLocalpartStmt, err = db.Prepare(deleteDevicesByLocalpartSQL); err != nil {
+		return
+	}
+	if s.selectDevicesByIDStmt, err = db.Prepare(selectDevicesByIDSQL); err != nil {
+		return
+	}
+	if s.updateDeviceLastSeenStmt, err = db.Prepare(updateDeviceLastSeen); err != nil {
+		return
+	}
+	s.serverName = server
+	return
+}
+
+// insertDevice creates a new device. Returns an error if any device with the same access token already exists.
+// Returns an error if the user already has a device with the given device ID.
+// Returns the device on success.
+func (s *devicesStatements) insertDevice(
+	ctx context.Context, txn *sql.Tx, id, localpart, accessToken string,
+	displayName *string, ipAddr, userAgent string,
+) (*api.Device, error) {
+	createdTimeMS := time.Now().UnixNano() / 1000000
+	var sessionID int64
+	countStmt := sqlutil.TxStmt(txn, s.selectDevicesCountStmt)
+	insertStmt := sqlutil.TxStmt(txn, s.insertDeviceStmt)
+	if err := countStmt.QueryRowContext(ctx).Scan(&sessionID); err != nil {
+		return nil, err
+	}
+	sessionID++
+	if _, err := insertStmt.ExecContext(ctx, id, localpart, accessToken, createdTimeMS, displayName, sessionID, createdTimeMS, ipAddr, userAgent); err != nil {
+		return nil, err
+	}
+	return &api.Device{
+		ID:          id,
+		UserID:      userutil.MakeUserID(localpart, s.serverName),
+		AccessToken: accessToken,
+		SessionID:   sessionID,
+		LastSeenTS:  createdTimeMS,
+		LastSeenIP:  ipAddr,
+		UserAgent:   userAgent,
+	}, nil
+}
+
+func (s *devicesStatements) deleteDevice(
+	ctx context.Context, txn *sql.Tx, id, localpart string,
+) error {
+	stmt := sqlutil.TxStmt(txn, s.deleteDeviceStmt)
+	_, err := stmt.ExecContext(ctx, id, localpart)
+	return err
+}
+
+func (s *devicesStatements) deleteDevices(
+	ctx context.Context, txn *sql.Tx, localpart string, devices []string,
+) error {
+	orig := strings.Replace(deleteDevicesSQL, "($2)", sqlutil.QueryVariadicOffset(len(devices), 1), 1)
+	prep, err := s.db.Prepare(orig)
+	if err != nil {
+		return err
+	}
+	stmt := sqlutil.TxStmt(txn, prep)
+	params := make([]interface{}, len(devices)+1)
+	params[0] = localpart
+	for i, v := range devices {
+		params[i+1] = v
+	}
+	_, err = stmt.ExecContext(ctx, params...)
+	return err
+}
+
+func (s *devicesStatements) deleteDevicesByLocalpart(
+	ctx context.Context, txn *sql.Tx, localpart, exceptDeviceID string,
+) error {
+	stmt := sqlutil.TxStmt(txn, s.deleteDevicesByLocalpartStmt)
+	_, err := stmt.ExecContext(ctx, localpart, exceptDeviceID)
+	return err
+}
+
+func (s *devicesStatements) updateDeviceName(
+	ctx context.Context, txn *sql.Tx, localpart, deviceID string, displayName *string,
+) error {
+	stmt := sqlutil.TxStmt(txn, s.updateDeviceNameStmt)
+	_, err := stmt.ExecContext(ctx, displayName, localpart, deviceID)
+	return err
+}
+
+func (s *devicesStatements) selectDeviceByToken(
+	ctx context.Context, accessToken string,
+) (*api.Device, error) {
+	var dev api.Device
+	var localpart string
+	stmt := s.selectDeviceByTokenStmt
+	err := stmt.QueryRowContext(ctx, accessToken).Scan(&dev.SessionID, &dev.ID, &localpart)
+	if err == nil {
+		dev.UserID = userutil.MakeUserID(localpart, s.serverName)
+		dev.AccessToken = accessToken
+	}
+	return &dev, err
+}
+
+// selectDeviceByID retrieves a device from the database with the given user
+// localpart and deviceID
+func (s *devicesStatements) selectDeviceByID(
+	ctx context.Context, localpart, deviceID string,
+) (*api.Device, error) {
+	var dev api.Device
+	var displayName sql.NullString
+	stmt := s.selectDeviceByIDStmt
+	err := stmt.QueryRowContext(ctx, localpart, deviceID).Scan(&displayName)
+	if err == nil {
+		dev.ID = deviceID
+		dev.UserID = userutil.MakeUserID(localpart, s.serverName)
+		if displayName.Valid {
+			dev.DisplayName = displayName.String
+		}
+	}
+	return &dev, err
+}
+
+func (s *devicesStatements) selectDevicesByLocalpart(
+	ctx context.Context, txn *sql.Tx, localpart, exceptDeviceID string,
+) ([]api.Device, error) {
+	devices := []api.Device{}
+	rows, err := sqlutil.TxStmt(txn, s.selectDevicesByLocalpartStmt).QueryContext(ctx, localpart, exceptDeviceID)
+
+	if err != nil {
+		return devices, err
+	}
+
+	for rows.Next() {
+		var dev api.Device
+		var lastseents sql.NullInt64
+		var id, displayname, ip, useragent sql.NullString
+		err = rows.Scan(&id, &displayname, &lastseents, &ip, &useragent)
+		if err != nil {
+			return devices, err
+		}
+		if id.Valid {
+			dev.ID = id.String
+		}
+		if displayname.Valid {
+			dev.DisplayName = displayname.String
+		}
+		if lastseents.Valid {
+			dev.LastSeenTS = lastseents.Int64
+		}
+		if ip.Valid {
+			dev.LastSeenIP = ip.String
+		}
+		if useragent.Valid {
+			dev.UserAgent = useragent.String
+		}
+
+		dev.UserID = userutil.MakeUserID(localpart, s.serverName)
+		devices = append(devices, dev)
+	}
+
+	return devices, nil
+}
+
+func (s *devicesStatements) selectDevicesByID(ctx context.Context, deviceIDs []string) ([]api.Device, error) {
+	sqlQuery := strings.Replace(selectDevicesByIDSQL, "($1)", sqlutil.QueryVariadic(len(deviceIDs)), 1)
+	iDeviceIDs := make([]interface{}, len(deviceIDs))
+	for i := range deviceIDs {
+		iDeviceIDs[i] = deviceIDs[i]
+	}
+
+	rows, err := s.db.QueryContext(ctx, sqlQuery, iDeviceIDs...)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "selectDevicesByID: rows.close() failed")
+	var devices []api.Device
+	for rows.Next() {
+		var dev api.Device
+		var localpart string
+		var displayName sql.NullString
+		if err := rows.Scan(&dev.ID, &localpart, &displayName); err != nil {
+			return nil, err
+		}
+		if displayName.Valid {
+			dev.DisplayName = displayName.String
+		}
+		dev.UserID = userutil.MakeUserID(localpart, s.serverName)
+		devices = append(devices, dev)
+	}
+	return devices, rows.Err()
+}
+
+func (s *devicesStatements) updateDeviceLastSeen(ctx context.Context, txn *sql.Tx, localpart, deviceID, ipAddr string) error {
+	lastSeenTs := time.Now().UnixNano() / 1000000
+	stmt := sqlutil.TxStmt(txn, s.updateDeviceLastSeenStmt)
+	_, err := stmt.ExecContext(ctx, lastSeenTs, ipAddr, localpart, deviceID)
+	return err
+}

userapi/storage/devices/cosmosdb/storage.go

@@ -0,0 +1,214 @@
+// Copyright 2017 Vector Creations Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cosmosdb
+
+import (
+	"context"
+	"crypto/rand"
+	"database/sql"
+	"encoding/base64"
+
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/matrix-org/dendrite/setup/config"
+	"github.com/matrix-org/dendrite/userapi/api"
+	"github.com/matrix-org/dendrite/userapi/storage/devices/sqlite3/deltas"
+	"github.com/matrix-org/gomatrixserverlib"
+
+	_ "github.com/mattn/go-sqlite3"
+)
+
+// The length of generated device IDs
+var deviceIDByteLength = 6
+
+// Database represents a device database.
+type Database struct {
+	db      *sql.DB
+	writer  sqlutil.Writer
+	devices devicesStatements
+}
+
+// NewDatabase creates a new device database
+func NewDatabase(dbProperties *config.DatabaseOptions, serverName gomatrixserverlib.ServerName) (*Database, error) {
+	db, err := sqlutil.Open(dbProperties)
+	if err != nil {
+		return nil, err
+	}
+	writer := sqlutil.NewExclusiveWriter()
+	d := devicesStatements{}
+
+	// Create tables before executing migrations so we don't fail if the table is missing,
+	// and THEN prepare statements so we don't fail due to referencing new columns
+	if err = d.execSchema(db); err != nil {
+		return nil, err
+	}
+	m := sqlutil.NewMigrations()
+	deltas.LoadLastSeenTSIP(m)
+	if err = m.RunDeltas(db, dbProperties); err != nil {
+		return nil, err
+	}
+	if err = d.prepare(db, writer, serverName); err != nil {
+		return nil, err
+	}
+	return &Database{db, writer, d}, nil
+}
+
+// GetDeviceByAccessToken returns the device matching the given access token.
+// Returns sql.ErrNoRows if no matching device was found.
+func (d *Database) GetDeviceByAccessToken(
+	ctx context.Context, token string,
+) (*api.Device, error) {
+	return d.devices.selectDeviceByToken(ctx, token)
+}
+
+// GetDeviceByID returns the device matching the given ID.
+// Returns sql.ErrNoRows if no matching device was found.
+func (d *Database) GetDeviceByID(
+	ctx context.Context, localpart, deviceID string,
+) (*api.Device, error) {
+	return d.devices.selectDeviceByID(ctx, localpart, deviceID)
+}
+
+// GetDevicesByLocalpart returns the devices matching the given localpart.
+func (d *Database) GetDevicesByLocalpart(
+	ctx context.Context, localpart string,
+) ([]api.Device, error) {
+	return d.devices.selectDevicesByLocalpart(ctx, nil, localpart, "")
+}
+
+func (d *Database) GetDevicesByID(ctx context.Context, deviceIDs []string) ([]api.Device, error) {
+	return d.devices.selectDevicesByID(ctx, deviceIDs)
+}
+
+// CreateDevice makes a new device associated with the given user ID localpart.
+// If there is already a device with the same device ID for this user, that access token will be revoked
+// and replaced with the given accessToken. If the given accessToken is already in use for another device,
+// an error will be returned.
+// If no device ID is given one is generated.
+// Returns the device on success.
+func (d *Database) CreateDevice(
+	ctx context.Context, localpart string, deviceID *string, accessToken string,
+	displayName *string, ipAddr, userAgent string,
+) (dev *api.Device, returnErr error) {
+	if deviceID != nil {
+		returnErr = d.writer.Do(d.db, nil, func(txn *sql.Tx) error {
+			var err error
+			// Revoke existing tokens for this device
+			if err = d.devices.deleteDevice(ctx, txn, *deviceID, localpart); err != nil {
+				return err
+			}
+
+			dev, err = d.devices.insertDevice(ctx, txn, *deviceID, localpart, accessToken, displayName, ipAddr, userAgent)
+			return err
+		})
+	} else {
+		// We generate device IDs in a loop in case its already taken.
+		// We cap this at going round 5 times to ensure we don't spin forever
+		var newDeviceID string
+		for i := 1; i <= 5; i++ {
+			newDeviceID, returnErr = generateDeviceID()
+			if returnErr != nil {
+				return
+			}
+
+			returnErr = d.writer.Do(d.db, nil, func(txn *sql.Tx) error {
+				var err error
+				dev, err = d.devices.insertDevice(ctx, txn, newDeviceID, localpart, accessToken, displayName, ipAddr, userAgent)
+				return err
+			})
+			if returnErr == nil {
+				return
+			}
+		}
+	}
+	return
+}
+
+// generateDeviceID creates a new device id. Returns an error if failed to generate
+// random bytes.
+func generateDeviceID() (string, error) {
+	b := make([]byte, deviceIDByteLength)
+	_, err := rand.Read(b)
+	if err != nil {
+		return "", err
+	}
+	// url-safe no padding
+	return base64.RawURLEncoding.EncodeToString(b), nil
+}
+
+// UpdateDevice updates the given device with the display name.
+// Returns SQL error if there are problems and nil on success.
+func (d *Database) UpdateDevice(
+	ctx context.Context, localpart, deviceID string, displayName *string,
+) error {
+	return d.writer.Do(d.db, nil, func(txn *sql.Tx) error {
+		return d.devices.updateDeviceName(ctx, txn, localpart, deviceID, displayName)
+	})
+}
+
+// RemoveDevice revokes a device by deleting the entry in the database
+// matching with the given device ID and user ID localpart.
+// If the device doesn't exist, it will not return an error
+// If something went wrong during the deletion, it will return the SQL error.
+func (d *Database) RemoveDevice(
+	ctx context.Context, deviceID, localpart string,
+) error {
+	return d.writer.Do(d.db, nil, func(txn *sql.Tx) error {
+		if err := d.devices.deleteDevice(ctx, txn, deviceID, localpart); err != sql.ErrNoRows {
+			return err
+		}
+		return nil
+	})
+}
+
+// RemoveDevices revokes one or more devices by deleting the entry in the database
+// matching with the given device IDs and user ID localpart.
+// If the devices don't exist, it will not return an error
+// If something went wrong during the deletion, it will return the SQL error.
+func (d *Database) RemoveDevices(
+	ctx context.Context, localpart string, devices []string,
+) error {
+	return d.writer.Do(d.db, nil, func(txn *sql.Tx) error {
+		if err := d.devices.deleteDevices(ctx, txn, localpart, devices); err != sql.ErrNoRows {
+			return err
+		}
+		return nil
+	})
+}
+
+// RemoveAllDevices revokes devices by deleting the entry in the
+// database matching the given user ID localpart.
+// If something went wrong during the deletion, it will return the SQL error.
+func (d *Database) RemoveAllDevices(
+	ctx context.Context, localpart, exceptDeviceID string,
+) (devices []api.Device, err error) {
+	err = d.writer.Do(d.db, nil, func(txn *sql.Tx) error {
+		devices, err = d.devices.selectDevicesByLocalpart(ctx, txn, localpart, exceptDeviceID)
+		if err != nil {
+			return err
+		}
+		if err := d.devices.deleteDevicesByLocalpart(ctx, txn, localpart, exceptDeviceID); err != sql.ErrNoRows {
+			return err
+		}
+		return nil
+	})
+	return
+}
+
+// UpdateDeviceLastSeen updates a the last seen timestamp and the ip address
+func (d *Database) UpdateDeviceLastSeen(ctx context.Context, localpart, deviceID, ipAddr string) error {
+	return d.writer.Do(d.db, nil, func(txn *sql.Tx) error {
+		return d.devices.updateDeviceLastSeen(ctx, txn, localpart, deviceID, ipAddr)
+	})
+}

userapi/storage/devices/storage.go

@@ -20,6 +20,7 @@ import (
 	"fmt"
 
 	"github.com/matrix-org/dendrite/setup/config"
+	"github.com/matrix-org/dendrite/userapi/storage/devices/cosmosdb"
 	"github.com/matrix-org/dendrite/userapi/storage/devices/postgres"
 	"github.com/matrix-org/dendrite/userapi/storage/devices/sqlite3"
 	"github.com/matrix-org/gomatrixserverlib"
@@ -29,6 +30,8 @@ import (
 // and sets postgres connection parameters
 func NewDatabase(dbProperties *config.DatabaseOptions, serverName gomatrixserverlib.ServerName) (Database, error) {
 	switch {
+	case dbProperties.ConnectionString.IsCosmosDB():
+		return cosmosdb.NewDatabase(dbProperties, serverName)
 	case dbProperties.ConnectionString.IsSQLite():
 		return sqlite3.NewDatabase(dbProperties, serverName)
 	case dbProperties.ConnectionString.IsPostgres():

userapi/storage/devices/storage_wasm.go

@@ -27,6 +27,8 @@ func NewDatabase(
 	serverName gomatrixserverlib.ServerName,
 ) (Database, error) {
 	switch {
+	case dbProperties.ConnectionString.IsCosmosDB():
+		return nil, fmt.Errorf("can't use CosmosDB implementation")
 	case dbProperties.ConnectionString.IsSQLite():
 		return sqlite3.NewDatabase(dbProperties, serverName)
 	case dbProperties.ConnectionString.IsPostgres():