dendrite/roomserver
Neil Alexander 192a7a7923
Roomserver input backpressure metric
Squashed commit of the following:

commit 56e934ac0aeedcfb2c072010959ba49734d4e0cb
Author: Neil Alexander <neilalexander@users.noreply.github.com>
Date:   Fri Jul 2 09:39:30 2021 +0100

    Fix metric

commit 3911f3a0c17b164b012e881c085ceca30f5de408
Author: Neil Alexander <neilalexander@users.noreply.github.com>
Date:   Fri Jul 2 09:36:29 2021 +0100

    Register correct metric

commit a9ddbfaed421538a701151801e9451198a8be4f3
Author: Neil Alexander <neilalexander@users.noreply.github.com>
Date:   Fri Jul 2 09:33:33 2021 +0100

    Try to capture RS input backpressure metric
2021-07-02 09:48:55 +01:00
..
acls Pass pointers to events — reloaded (#1583) 2020-11-16 15:44:53 +00:00
api Fix appsevice alias queries part 2 (#1684) 2021-03-03 17:00:31 +00:00
auth Pass pointers to events — reloaded (#1583) 2020-11-16 15:44:53 +00:00
internal Roomserver input backpressure metric 2021-07-02 09:48:55 +01:00
inthttp Peeking over federation via MSC2444 (#1391) 2021-01-22 14:55:08 +00:00
state Increase gocyclo complexity to 25 (and remove all but 2 golint directives related to it) (#1783) 2021-03-03 14:35:57 +00:00
storage db migration: fix #1844 and add additional assertions (#1889) 2021-06-29 11:25:17 +01:00
types State storage refactor (#1839) 2021-04-26 13:25:57 +01:00
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.go Top-level setup package (#1605) 2020-12-02 17:41:00 +00:00
roomserver_test.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 |
+---------------+-------------------+------------------+----------+