Fix database lock errors in User API in SQLite mode

userapi/storage/accounts/sqlite3/profile_table.go

@@ -93,15 +93,15 @@ func (s *profilesStatements) selectProfileByLocalpart(
 }
 
 func (s *profilesStatements) setAvatarURL(
-	ctx context.Context, localpart string, avatarURL string,
+	ctx context.Context, txn *sql.Tx, localpart string, avatarURL string,
 ) (err error) {
-	_, err = s.setAvatarURLStmt.ExecContext(ctx, avatarURL, localpart)
+	_, err = txn.Stmt(s.setAvatarURLStmt).ExecContext(ctx, avatarURL, localpart)
 	return
 }
 
 func (s *profilesStatements) setDisplayName(
-	ctx context.Context, localpart string, displayName string,
+	ctx context.Context, txn *sql.Tx, localpart string, displayName string,
 ) (err error) {
-	_, err = s.setDisplayNameStmt.ExecContext(ctx, displayName, localpart)
+	_, err = txn.Stmt(s.setDisplayNameStmt).ExecContext(ctx, displayName, localpart)
 	return
 }

userapi/storage/accounts/sqlite3/storage.go

@@ -20,7 +20,6 @@ import (
 	"encoding/json"
 	"errors"
 	"strconv"
-	"sync"
 
 	"github.com/matrix-org/dendrite/clientapi/auth/authtypes"
 	"github.com/matrix-org/dendrite/internal/sqlutil"
@@ -40,7 +39,9 @@ type Database struct {
 	threepids    threepidStatements
 	serverName   gomatrixserverlib.ServerName
 
-	createAccountMu sync.Mutex
+	accountWriter  *sqlutil.TransactionWriter
+	profileWriter  *sqlutil.TransactionWriter
+	threepidWriter *sqlutil.TransactionWriter
 }
 
 // NewDatabase creates a new accounts and profiles database
@@ -74,7 +75,18 @@ func NewDatabase(dataSourceName string, serverName gomatrixserverlib.ServerName)
 	if err = t.prepare(db); err != nil {
 		return nil, err
 	}
-	return &Database{db, partitions, a, p, ac, t, serverName, sync.Mutex{}}, nil
+	return &Database{
+		db:                        db,
+		PartitionOffsetStatements: partitions,
+		accounts:                  a,
+		profiles:                  p,
+		accountDatas:              ac,
+		threepids:                 t,
+		serverName:                serverName,
+		accountWriter:             sqlutil.NewTransactionWriter(),
+		profileWriter:             sqlutil.NewTransactionWriter(),
+		threepidWriter:            sqlutil.NewTransactionWriter(),
+	}, nil
 }
 
 // GetAccountByPassword returns the account associated with the given localpart and password.
@@ -105,7 +117,9 @@ func (d *Database) GetProfileByLocalpart(
 func (d *Database) SetAvatarURL(
 	ctx context.Context, localpart string, avatarURL string,
 ) error {
-	return d.profiles.setAvatarURL(ctx, localpart, avatarURL)
+	return d.profileWriter.Do(d.db, 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
@@ -113,7 +127,9 @@ func (d *Database) SetAvatarURL(
 func (d *Database) SetDisplayName(
 	ctx context.Context, localpart string, displayName string,
 ) error {
-	return d.profiles.setDisplayName(ctx, localpart, displayName)
+	return d.profileWriter.Do(d.db, func(txn *sql.Tx) error {
+		return d.profiles.setDisplayName(ctx, txn, localpart, displayName)
+	})
 }
 
 // CreateGuestAccount makes a new guest account and creates an empty profile
@@ -124,9 +140,7 @@ func (d *Database) CreateGuestAccount(ctx context.Context) (acc *api.Account, er
 	// 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.createAccountMu.Lock()
+	err = d.accountWriter.Do(d.db, func(txn *sql.Tx) error {
-	defer d.createAccountMu.Unlock()
-	err = sqlutil.WithTransaction(d.db, func(txn *sql.Tx) error {
 		var numLocalpart int64
 		numLocalpart, err = d.accounts.selectNewNumericLocalpart(ctx, txn)
 		if err != nil {
@@ -146,9 +160,7 @@ 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.createAccountMu.Lock()
+	err = d.accountWriter.Do(d.db, func(txn *sql.Tx) error {
-	defer d.createAccountMu.Unlock()
-	err = sqlutil.WithTransaction(d.db, func(txn *sql.Tx) error {
 		acc, err = d.createAccount(ctx, txn, localpart, plaintextPassword, appserviceID)
 		return err
 	})
@@ -196,7 +208,7 @@ func (d *Database) createAccount(
 func (d *Database) SaveAccountData(
 	ctx context.Context, localpart, roomID, dataType string, content json.RawMessage,
 ) error {
-	return sqlutil.WithTransaction(d.db, func(txn *sql.Tx) error {
+	return d.accountWriter.Do(d.db, func(txn *sql.Tx) error {
 		return d.accountDatas.insertAccountData(ctx, txn, localpart, roomID, dataType, content)
 	})
 }
@@ -247,7 +259,7 @@ var Err3PIDInUse = errors.New("This third-party identifier is already in use")
 func (d *Database) SaveThreePIDAssociation(
 	ctx context.Context, threepid, localpart, medium string,
 ) (err error) {
-	return sqlutil.WithTransaction(d.db, func(txn *sql.Tx) error {
+	return d.threepidWriter.Do(d.db, func(txn *sql.Tx) error {
 		user, err := d.threepids.selectLocalpartForThreePID(
 			ctx, txn, threepid, medium,
 		)
@@ -270,7 +282,9 @@ func (d *Database) SaveThreePIDAssociation(
 func (d *Database) RemoveThreePIDAssociation(
 	ctx context.Context, threepid string, medium string,
 ) (err error) {
-	return d.threepids.deleteThreePID(ctx, threepid, medium)
+	return d.threepidWriter.Do(d.db, func(txn *sql.Tx) error {
+		return d.threepids.deleteThreePID(ctx, txn, threepid, medium)
+	})
 }
 
 // GetLocalpartForThreePID looks up the localpart associated with a given third-party

userapi/storage/accounts/sqlite3/threepid_table.go

@@ -124,7 +124,8 @@ func (s *threepidStatements) insertThreePID(
 }
 
 func (s *threepidStatements) deleteThreePID(
-	ctx context.Context, threepid string, medium string) (err error) {
+	ctx context.Context, txn *sql.Tx, threepid string, medium string) (err error) {
-	_, err = s.deleteThreePIDStmt.ExecContext(ctx, threepid, medium)
+	stmt := sqlutil.TxStmt(txn, s.deleteThreePIDStmt)
+	_, err = stmt.ExecContext(ctx, threepid, medium)
 	return
 }