dendrite/roomserver
Neil Alexander 244ff0dccb
Don't create so many state snapshots when updating forward extremities (#1718)
* Light-weight checking of state changes when updating forward extremities

* Only do this for non-state events, since state events will always result in state change at extremities
2021-01-18 13:21:33 +00:00
..
acls Pass pointers to events — reloaded (#1583) 2020-11-16 15:44:53 +00:00
api Fix #1655 by re-adding the appservice alias query (#1660) 2020-12-18 13:33:28 +00:00
auth Pass pointers to events — reloaded (#1583) 2020-11-16 15:44:53 +00:00
internal Don't create so many state snapshots when updating forward extremities (#1718) 2021-01-18 13:21:33 +00:00
inthttp Fix #1655 by re-adding the appservice alias query (#1660) 2020-12-18 13:33:28 +00:00
state Don't create so many state snapshots when updating forward extremities (#1718) 2021-01-18 13:21:33 +00:00
storage Add RoomInfo cache, remove RoomServerRoomNIDsCache (#1646) 2020-12-16 12:15:12 +00:00
types Pass pointers to events — reloaded (#1583) 2020-11-16 15:44:53 +00:00
version Set default room version to v6 (#1438) 2020-09-25 12:59:57 +01:00
README.md use go module for dependencies (#594) 2019-05-21 21:56:55 +01:00
roomserver_test.go Top-level setup package (#1605) 2020-12-02 17:41:00 +00:00
roomserver.go Top-level setup package (#1605) 2020-12-02 17:41:00 +00:00

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 |
+---------------+-------------------+------------------+----------+