dendrite/roomserver
Kegsay 6d832ae544
Implement backfill in the roomserver (#983)
* Initial cut for backfilling

The syncserver now asks the roomserver via QueryBackfill (which already
existed to *handle* backfill requests) which then makes federation requests
via gomatrixserverlib.RequestBackfill.

Currently, tests fail on subsequent /messages requests because we don't know
which servers are in the room, because we are unable to get state snapshots
from a backfilled event because that code doesn't exist yet.

* WIP backfill, doesn't work

* Make initial backfill pass checks

* Persist backfilled events with state snapshots

* Remove debug lines

* Linting

* Review comments
2020-04-28 11:46:47 +01:00
..
alias Move /room/{roomID}/state endpoints into client API (#606) (#962) 2020-04-14 18:36:08 +01:00
api Implement backfill in the roomserver (#983) 2020-04-28 11:46:47 +01:00
auth Implement backfill over federation (#938) 2020-03-24 12:20:10 +00:00
input Implement backfill in the roomserver (#983) 2020-04-28 11:46:47 +01:00
query Implement backfill in the roomserver (#983) 2020-04-28 11:46:47 +01:00
state Use a single storage.Database interface (#978) 2020-04-24 10:38:58 +01:00
storage Implement backfill in the roomserver (#983) 2020-04-28 11:46:47 +01:00
types Invites v2 endpoint (#952) 2020-04-03 14:29:06 +01:00
version Set default room version to 4 (#957) 2020-04-16 12:53:27 +01:00
README.md use go module for dependencies (#594) 2019-05-21 21:56:55 +01:00
roomserver.go Implement backfill in the roomserver (#983) 2020-04-28 11:46:47 +01:00

README.md

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