5267cc0f54
The previous version was getting **ALL** membership events (as
`ClientEvents`, so going through `NewEventFromTrustedJSONWithID`) for a
given room.
Now we are querying only locally joined users as `ClientEvents`, which
should **significantly** reduce allocations.
Take for example a large room with 2k membership events, but only 1
local user - avoiding 1999 `NewEventFromTrustedJSONWithID` calls just to
calculate the `roomSize` which we can also query by other means.
This is also getting called for every `OutputRoomEvent` in the userAPI.
Benchmark with 1 local user and 100 remote users.
```
pkg: github.com/matrix-org/dendrite/userapi/consumers
cpu: 12th Gen Intel(R) Core(TM) i5-12500H
│ old.txt │ new.txt │
│ sec/op │ sec/op vs base │
LocalRoomMembers-16 375.9µ ± 7% 327.6µ ± 6% -12.85% (p=0.000 n=10)
│ old.txt │ new.txt │
│ B/op │ B/op vs base │
LocalRoomMembers-16 79.426Ki ± 0% 8.507Ki ± 0% -89.29% (p=0.000 n=10)
│ old.txt │ new.txt │
│ allocs/op │ allocs/op vs base │
LocalRoomMembers-16 1015.0 ± 0% 277.0 ± 0% -72.71% (p=0.000 n=10)
```
|
||
|---|---|---|
| .. | ||
| acls | ||
| api | ||
| auth | ||
| internal | ||
| producers | ||
| state | ||
| storage | ||
| types | ||
| version | ||
| README.md | ||
| roomserver.go | ||
| roomserver_test.go | ||
RoomServer
RoomServer Internals
Numeric IDs
To save space matrix string identifiers are mapped to local numeric IDs. The numeric IDs are more efficient to manipulate and use less space to store. The numeric IDs are never exposed in the API the room server exposes. The numeric IDs are converted to string IDs before they leave the room server. The numeric ID for a string ID is never 0 to avoid being confused with go's default zero value. Zero is used to indicate that there was no corresponding string ID. Well-known event types and event state keys are preassigned numeric IDs.
State Snapshot Storage
The room server stores the state of the matrix room at each event. For efficiency the state is stored as blocks of 3-tuples of numeric IDs for the event type, event state key and event ID. For further efficiency the state snapshots are stored as the combination of up to 64 these blocks. This allows blocks of the room state to be reused in multiple snapshots.
The resulting database tables look something like this:
+-------------------------------------------------------------------+
| Events |
+---------+-------------------+------------------+------------------+
| EventNID| EventTypeNID | EventStateKeyNID | StateSnapshotNID |
+---------+-------------------+------------------+------------------+
| 1 | m.room.create 1 | "" 1 | <nil> 0 |
| 2 | m.room.member 2 | "@user:foo" 2 | <nil> 0 |
| 3 | m.room.member 2 | "@user:bar" 3 | {1,2} 1 |
| 4 | m.room.message 3 | <nil> 0 | {1,2,3} 2 |
| 5 | m.room.member 2 | "@user:foo" 2 | {1,2,3} 2 |
| 6 | m.room.message 3 | <nil> 0 | {1,3,6} 3 |
+---------+-------------------+------------------+------------------+
+----------------------------------------+
| State Snapshots |
+-----------------------+----------------+
| EventStateSnapshotNID | StateBlockNIDs |
+-----------------------+----------------|
| 1 | {1} |
| 2 | {1,2} |
| 3 | {1,2,3} |
+-----------------------+----------------+
+-----------------------------------------------------------------+
| State Blocks |
+---------------+-------------------+------------------+----------+
| StateBlockNID | EventTypeNID | EventStateKeyNID | EventNID |
+---------------+-------------------+------------------+----------+
| 1 | m.room.create 1 | "" 1 | 1 |
| 1 | m.room.member 2 | "@user:foo" 2 | 2 |
| 2 | m.room.member 2 | "@user:bar" 3 | 3 |
| 3 | m.room.member 2 | "@user:foo" 2 | 6 |
+---------------+-------------------+------------------+----------+