59 Commits
Author SHA1 Message Date
Olivier 'reivilibre 9761f9bc42 Merge branch 'master' into develop 2026-07-28 14:39:05 +01:00
Olivier 'reivilibreandOlivier 'reivilibre 0a2456fef3 Validate room name, avatar and heroes' profile fields before sending down sliding sync as trusted fields
Fixes: https://github.com/element-hq/synapse/security/advisories/GHSA-jhcg-5392-5mjw
Fixes: https://github.com/matrix-org/internal-config/issues/1751

I introduce some stricter JSON types that don't break down to `Any` — it seems these have become possible since our last attempt.
(I'm pretty sure mypy wouldn't let you do this a few years ago.)
Our `dict[str, Any]` type is such a footgun. I'd like to spread this out further, but will do so after the security release.

I then use these stricter JSON types on everything the sliding sync handler pulls out of `event.content` and therefore get forced into a bare minimum level of validation, by the type checker.

-----

Reviewed-on: https://github.com/element-hq/synapse-private/pull/151
2026-07-28 13:58:06 +01:00
夜坂雅andGitHub 5ed830b3b4 Change default room version to 11 (MSC4239) (#18680)
Fix #18530

Complement test changes: https://github.com/matrix-org/complement/pull/858

SyTest changes: https://github.com/matrix-org/sytest/pull/1422
2026-07-16 12:33:13 -05:00
Eric EastwoodandGitHub 026937b251 Update FakeChannel.await_result(...) to drive async Rust (Tokio runtime/thread pool) (#19879)
Split off from https://github.com/element-hq/synapse/pull/19878 (needed
to drive requests in tests that use async Rust)

Follow-up to https://github.com/element-hq/synapse/pull/19871
2026-07-07 04:07:19 -05:00
16fe5fb462 Expose MSC4354 Sticky Events over MSC4186 (Simplified) Sliding Sync. (#19591)
Follows: #19487
Part of: MSC4354 whose experimental feature tracking issue is #19409

This PR implements the Sliding Sync (MSC4186) extension described in
MSC4354, allowing sliding sync clients
to receive sticky events in a reliable way.

The logic is much the same as for oldschool sync (implementation in
#19487),
although in the sliding sync extension, the client can choose their own
limit
and must control their own pagination through an extra token in the
extension request/response bodies.

Note this does not yet send down existing sticky events in the
room when the room has been newly-joined.
This newly-discovered gap is tracked at #19662 and will be addressed for
both current sync and MSC4186 SSS soon.

---------

Signed-off-by: Olivier 'reivilibre <oliverw@matrix.org>
Co-authored-by: Eric Eastwood <erice@element.io>
2026-06-23 13:04:36 +00:00
8c9b1ff877 Reintroduce #19714 - Send a SSS response immediately if the config has changed (#19792)
Reintroduces #19714, after being reverted in #19784.

Fix https://github.com/element-hq/synapse/issues/18844
Fix https://github.com/element-hq/synapse/issues/19783
Fix https://github.com/element-hq/synapse/issues/18880

This PR also adds a fix so that we don't always return immediately when
using the e2ee extension.

---------

Co-authored-by: Benjamin Bouvier <benjamin@bouvier.cc>
Co-authored-by: Eric Eastwood <madlittlemods@gmail.com>
Co-authored-by: Eric Eastwood <erice@element.io>
2026-06-08 11:42:57 +01:00
Joe GroocockandGitHub 966e193e4e Fix sending heroes in SSS when m.room.name="" (#19468)
As per the spec, a room with m.room.name value that is absent, null or
empty should be treated as if there is no m.room.name event at all:
https://spec.matrix.org/v1.17/client-server-api/#mroomname

This fetches the full m.room.name event and checks the content.name
instead of only checking the existence of the m.room.name event. This
results in correctly sending heroes for those rooms.

Fixes: https://github.com/element-hq/synapse/issues/19447

Signed-off-by: Joe Groocock <me@frebib.net>
2026-05-20 12:10:54 +01:00
Olivier 'reivilibreandGitHub 3f0f03d536 Revert "Send a SSS response immediately if the config has changed and there are new results to sync (#19714)" (#19784)
Reverts: #19714

Opens: #19783

Closes: https://github.com/element-hq/backend-internal/issues/242

Related: #18880 (the performance problem that is aggravated by #19714)

This reverts commit 2691d0b8b1.

---------

Signed-off-by: Olivier 'reivilibre <oliverw@matrix.org>
2026-05-15 10:36:47 +00:00
Erik JohnstonandGitHub ff55aff5b2 Fix up event-construction in tests ahead of the Rust event port (#19781)
When we port the `Event` class to Rust, the constructor will check for
the existence of required fields. To support that, we tidy up the test
code where we construct fake events to add all the required fields.

There should be no behavioural changes.

Review commit-by-commit.
2026-05-15 10:12:42 +01:00
2691d0b8b1 Send a SSS response immediately if the config has changed and there are new results to sync (#19714)
This fixes the bug described in #19713 (and double-checked against the
SDK integration test, which now passes with this change). A sync
response must be returned immediately if a room subscription
configuration change caused a new non-empty response (checked with `if
response` in the code) to be produced.

Fixes #19713.
Fixes #18844.

---------

Co-authored-by: Erik Johnston <erik@matrix.org>
2026-04-24 10:18:05 +00:00
Olivier 'reivilibreandGitHub 52c05c5ca4 Introduce spam_checker_spammy internal event metadata. (#19453)
Follows: #19365

Part of: MSC4354 Sticky Events (experimental feature #19409)

This PR introduces a `spam_checker_spammy` flag, analogous to
`policy_server_spammy`, as an explicit flag
that an event was decided to be spammy by a spam-checker module.

The original Sticky Events PR (#18968) just reused
`policy_server_spammy`, but it didn't sit right with me
because we (at least appear to be experimenting with features that)
allow users to opt-in to seeing
`policy_server_spammy` events (presumably for moderation purposes).

Keeping these flags separate felt best, therefore.

As for why we need this flag: soon soft-failed status won't be
permanent, at least for sticky events.
The spam checker modules currently work by making events soft-failed.
We want to prevent spammy events from getting
reconsidered/un-soft-failed, so it seems like we need
a flag to track spam-checker spamminess *separately* from soft-failed.

Should be commit-by-commit friendly, but is also small.

---------

Signed-off-by: Olivier 'reivilibre <oliverw@matrix.org>
2026-04-15 16:53:23 +01:00
dfd00a986f Fix sliding sync performance slow down for long lived connections. (#19206)
Fixes https://github.com/element-hq/synapse/issues/19175

This PR moves tracking of what lazy loaded membership we've sent to each
room out of the required state table. This avoids that table from
continuously growing, which massively helps performance as we pull out
all matching rows for the connection when we receive a request.

The new table is only read when we have data in a room to send, so we
end up reading a lot fewer rows from the DB. Though we now read from
that table for every room we have events to return in, rather than once
at the start of the request.

For an explanation of how the new table works, see the
[comment](https://github.com/element-hq/synapse/blob/erikj/sss_better_membership_storage2/synapse/storage/schema/main/delta/93/02_sliding_sync_members.sql#L15-L38)
on the table schema.

The table is designed so that we can later prune old entries if we wish,
but that is not implemented in this PR.

Reviewable commit-by-commit.

---------

Co-authored-by: Eric Eastwood <erice@element.io>
2025-12-12 10:02:57 +00:00
Erik JohnstonandGitHub b74c29f694 Move towards a dedicated Duration class (#19223)
We have various constants to try and avoid mistyping of durations, e.g.
`ONE_HOUR_SECONDS * MILLISECONDS_PER_SECOND`, however this can get a
little verbose and doesn't help with typing.

Instead, let's move towards a dedicated `Duration` class (basically a
[`timedelta`](https://docs.python.org/3/library/datetime.html#timedelta-objects)
with helper methods).

This PR introduces the new types and converts all usages of the existing
constants with it. Future PRs may work to move the clock methods to also
use it (e.g. `call_later` and `looping_call`).

Reviewable commit-by-commit.
2025-11-26 10:56:59 +00:00
db975ea10d Expire sliding sync connections (#19211)
We add some logic to expire sliding sync connections if they get old or
if there is too much pending data to return.

The values of the constants are picked fairly arbitrarily, these are
currently:
1. More than 100 rooms with pending events if the connection hasn't been
used in over an hour
2. The connection hasn't been used for over a week

Reviewable commit-by-commit

---------

Co-authored-by: Eric Eastwood <erice@element.io>
2025-11-25 10:20:47 +00:00
Andrew FerrazzuttiandGitHub fcac7e0282 Write union types as X | Y where possible (#19111)
aka PEP 604, added in Python 3.10
2025-11-06 14:02:33 -06:00
Andrew FerrazzuttiandGitHub fc244bb592 Use type hinting generics in standard collections (#19046)
aka PEP 585, added in Python 3.9

 - https://peps.python.org/pep-0585/
 - https://docs.astral.sh/ruff/rules/non-pep585-annotation/
2025-10-22 16:48:19 -05:00
Eric EastwoodandGitHub 5a9ca1e3d9 Introduce Clock.call_when_running(...) to include logcontext by default (#18944)
Introduce `Clock.call_when_running(...)` to wrap startup code in a
logcontext, ensuring we can identify which server generated the logs.

Background:

>  Ideally, nothing from the Synapse homeserver would be logged against the `sentinel` 
>  logcontext as we want to know which server the logs came from. In practice, this is not 
>  always the case yet especially outside of request handling. 
>   
>  Global things outside of Synapse (e.g. Twisted reactor code) should run in the 
>  `sentinel` logcontext. It's only when it calls into application code that a logcontext 
>  gets activated. This means the reactor should be started in the `sentinel` logcontext, 
>  and any time an awaitable yields control back to the reactor, it should reset the 
>  logcontext to be the `sentinel` logcontext. This is important to avoid leaking the 
>  current logcontext to the reactor (which would then get picked up and associated with 
>  the next thing the reactor does). 
>
> *-- `docs/log_contexts.md`

Also adds a lint to prefer `Clock.call_when_running(...)` over
`reactor.callWhenRunning(...)`

Part of https://github.com/element-hq/synapse/issues/18905
2025-09-22 10:27:59 -05:00
ada3a3b2b3 Add experimental support for MSC4308: Thread Subscriptions extension to Sliding Sync when MSC4306 and MSC4186 are enabled. (#18695)
Closes: #18436

Implements:
https://github.com/matrix-org/matrix-spec-proposals/pull/4308

Follows: #18674

Adds an extension to Sliding Sync and a companion
endpoint needed for backpaginating missed thread subscription changes,
as described in MSC4308

---------

Signed-off-by: Olivier 'reivilibre <oliverw@matrix.org>
Co-authored-by: Andrew Morgan <1342360+anoadragon453@users.noreply.github.com>
2025-09-11 14:45:04 +01:00
reivilibreandGitHub a31d53b28f Use twisted.internet.testing module in tests instead of deprecated twisted.test.proto_helpers. (#18728)
Follows: #18727

---------

Signed-off-by: Olivier 'reivilibre <oliverw@matrix.org>
2025-07-30 12:32:10 +01:00
1709957395 Fix bug where sliding sync ignored room_id_to_include option (#18535)
This was correctly handled for the "fallback" case where the background
updates hadn't finished

---------

Co-authored-by: Eric Eastwood <erice@element.io>
2025-06-13 11:29:23 +01:00
dependabot[bot]GitHubdependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>Andrew MorganAndrew Morgan
9d43bec326 Bump ruff from 0.7.3 to 0.11.10 (#18451)
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Andrew Morgan <andrew@amorgan.xyz>
Co-authored-by: Andrew Morgan <1342360+anoadragon453@users.noreply.github.com>
2025-05-20 15:23:30 +01:00
7c633f1a58 Pass leave from remote invite rejection down Sliding Sync (#18375)
Fixes #17753 


### Dev notes

The `sliding_sync_membership_snapshots` and `sliding_sync_joined_rooms`
database tables were added in
https://github.com/element-hq/synapse/pull/17512

### Pull Request Checklist

<!-- Please read
https://element-hq.github.io/synapse/latest/development/contributing_guide.html
before submitting your pull request -->

* [X] Pull request is based on the develop branch
* [x] Pull request includes a [changelog
file](https://element-hq.github.io/synapse/latest/development/contributing_guide.html#changelog).
The entry should:
- Be a short description of your change which makes sense to users.
"Fixed a bug that prevented receiving messages from other servers."
instead of "Moved X method from `EventStore` to `EventWorkerStore`.".
  - Use markdown where necessary, mostly for `code blocks`.
  - End with either a period (.) or an exclamation mark (!).
  - Start with a capital letter.
- Feel free to credit yourself, by adding a sentence "Contributed by
@github_username." or "Contributed by [Your Name]." to the end of the
entry.
* [X] [Code
style](https://element-hq.github.io/synapse/latest/code_style.html) is
correct
(run the
[linters](https://element-hq.github.io/synapse/latest/development/contributing_guide.html#run-the-linters))

---------

Co-authored-by: Erik Johnston <erik@matrix.org>
Co-authored-by: Olivier 'reivilibre <oliverw@matrix.org>
Co-authored-by: Eric Eastwood <erice@element.io>
2025-05-08 14:28:23 +00:00
Eric EastwoodandGitHub aab3672037 Bust _membership_stream_cache cache when current state changes (#17732)
This is particularly a problem in a state reset scenario where the membership
might change without a corresponding event.

This PR is targeting a scenario where a state reset happens which causes
room membership to change. Previously, the cache would just hold onto
stale data and now we properly bust the cache in this scenario.

We have a few tests for these scenarios which you can see are now fixed
because we can remove the `FIXME` where we were previously manually
busting the cache in the test itself.

This is a general Synapse thing so by it's nature it helps out Sliding
Sync.

Fix https://github.com/element-hq/synapse/issues/17368

Prerequisite for https://github.com/element-hq/synapse/issues/17929

---

Match when are busting `_curr_state_delta_stream_cache`
2025-01-08 10:11:09 -06:00
Quentin Gliech 657dd5151e Merge branch 'master' into develop 2024-12-03 17:44:48 +01:00
Eric EastwoodandQuentin Gliech 4daa533e82 Sliding Sync: Fix state leaking on incremental sync 2024-12-03 09:53:21 +01:00
Eric EastwoodandGitHub e5d3bfba30 Sliding Sync: Include invite, ban, kick, targets when $LAZY-loading room members (#17947)
Part of https://github.com/element-hq/synapse/issues/17929
2024-12-02 10:17:55 -06:00
Eric EastwoodandGitHub 0932c77539 Sliding Sync: Lazy-loading room members on incremental sync (remember memberships) (#17809)
Lazy-loading room members on incremental sync and remember which
memberships we've sent down the connection before (up-to 100)

Fix https://github.com/element-hq/synapse/issues/17804
2024-11-04 10:17:58 -06:00
Eric EastwoodandGitHub a5e16a4ab5 Sliding Sync: Reset forgotten status when membership changes (like rejoining a room) (#17835)
Reset `sliding_sync_membership_snapshots` -> `forgotten` status when
membership changes (like rejoining a room).

Fix https://github.com/element-hq/synapse/issues/17781

### What was the problem before?

Previously, if someone used `/forget` on one of their rooms, it would
update `sliding_sync_membership_snapshots` as expected but when someone
rejoined the room (or had any membership change), the upsert didn't
overwrite and reset the `forgotten` status so it remained `forgotten`
and invisible down the Sliding Sync endpoint.
2024-10-22 11:06:46 +01:00
d025b5ab50 Correctly changes to required state config in sliding sync (#17785)
Fixes https://github.com/element-hq/synapse/issues/17698

This handles `required_state` changes by checking if new state has been
added to the config, and if so fetching and returning that from the
current state.

This also takes care to ensure that given a state entry S that is added,
removed and then re-added that we do *not* send S down a second time if
there have been no changes to S in the current state. This is fine for
Rust SDK (as it just remembers all state), but we might decide not to do
this behaviour in the MSC. If we decide to always send down S then its
easy enough to rip out all the code.

---------

Co-authored-by: Eric Eastwood <eric.eastwood@beta.gouv.fr>
2024-10-14 13:31:22 +01:00
Erik JohnstonandGitHub 422f3ecec1 Sliding sync: omit bump stamp when it is unchanged (#17788)
This saves some DB lookups in rooms
2024-10-08 11:17:23 +01:00
a851f6b237 Sliding sync: Add connection tracking to the account_data extension (#17695)
This is basically exactly the same logic as for receipts. Essentially we
just need to track which room account data we have and haven't sent down
to clients, and use that when we pull stuff out.

I think this just needs a couple of extra tests written

---------

Co-authored-by: Eric Eastwood <eric.eastwood@beta.gouv.fr>
2024-09-19 19:51:51 +01:00
c2e5e9e67c Sliding Sync: Avoid fetching left rooms and add back newly_left rooms (#17725)
Performance optimization: We can avoid fetching rooms that the user has
left themselves (which could be a significant amount), then only add
back rooms that the user has `newly_left` (left in the token range of an
incremental sync). It's a lot faster to fetch less rooms than fetch them
all and throw them away in most cases. Since the user only leaves a room
(or is state reset out) once in a blue moon, we can avoid a lot of work.

Based on @erikjohnston's branch, erikj/ss_perf


---------

Co-authored-by: Erik Johnston <erik@matrix.org>
2024-09-19 10:07:18 -05:00
Erik JohnstonandGitHub 07a51d2a56 Fix sliding sync for rooms with unknown room version (#17733)
Follow on from #17727
2024-09-19 14:01:11 +01:00
Eric EastwoodandGitHub a9c0e27eb7 Sliding Sync: No need to sort if the range is large enough to cover all of the rooms (#17731)
No need to sort if the range is large enough to cover all of the rooms
in the list. Previously, we would only do this optimization if the range
was exactly large enough.

Follow-up to https://github.com/element-hq/synapse/pull/17672
2024-09-19 09:33:34 +01:00
Eric EastwoodandGitHub af998e6c66 Sliding sync: Ignore invites from ignored users (#17729)
`m.ignored_user_list` in account data
2024-09-18 18:09:23 -05:00
Eric EastwoodandGitHub 03937a1cae Sliding Sync: Return room tags in account data extension (#17707)
The account data extension was also updated to avoid copies when we pull
the data out of the cache.

Fix https://github.com/element-hq/synapse/issues/17694
2024-09-16 13:47:35 -05:00
4ac783549c Sliding Sync: Support filtering by 'tags' / 'not_tags' in SSS (#17662)
This appears to be enough to make Element Web work (or at least move it
on to the next hurdle)

---------

Co-authored-by: Eric Eastwood <eric.eastwood@beta.gouv.fr>
2024-09-12 20:18:19 -05:00
Eric EastwoodandGitHub 9b83fb7c16 Sliding Sync: Move filters tests to rest layer (#17703)
Move filters tests to rest layer in order to test the new (with sliding
sync tables) and fallback paths that Sliding Sync can use.

Also found a bug in the new path because it's not being tested which is
also fixed in this PR. We now take into account `has_known_state` when
filtering.

Spawning from
https://github.com/element-hq/synapse/pull/17662#discussion_r1755574791.
This should have been done when we started using the new sliding sync
tables in https://github.com/element-hq/synapse/pull/17630
2024-09-12 15:27:03 -05:00
Eric EastwoodandGitHub e4a1f271b9 Sliding Sync: Make sure we get up-to-date information from get_sliding_sync_rooms_for_user(...) (#17692)
We need to bust the `get_sliding_sync_rooms_for_user`
cache when the room encryption is updated and any
other field that is used in the query.

Follow-up to https://github.com/element-hq/synapse/pull/17630

- Bust cache for membership change (cross-reference
`get_rooms_for_user`)
- Bust cache for room `encryption` (cross-reference
`get_room_encryption`)
- Bust cache for `forgotten` (cross-reference
`did_forget`/`get_forgotten_rooms_for_user`)
2024-09-11 12:13:54 -05:00
Erik JohnstonandGitHub f6c2b0ec2e Sliding sync: don't fetch room summary for named rooms. (#17683)
For rooms with a name we can skip fetching a full room summary, as we
don't need to calculate heroes, and instead just fetch the room counts
directly.

This also changes things to not return counts and heroes for non-joined
rooms. For left/banned rooms we were returning zero values anyway, and
for invite/knock rooms we don't really want to leak such information
(even if some of is included in the stripped state).
2024-09-11 13:16:57 +01:00
Erik JohnstonandGitHub 588e5b521d Sliding Sync: Retrieve fewer events from DB in sync (#17688)
When using timeline limit of 1 we end up fetching 2 events from the DB
purely to tell if the response was "limited" or not. Lets not do that.
2024-09-10 09:52:42 +01:00
Eric EastwoodandGitHub 5389374ef8 Sliding Sync: Speed up incremental sync by avoiding extra work (#17665)
Speed up incremental sync by avoiding extra work. We first look at the
state delta changes and only fetch and calculate further derived things
if they have changed.
2024-09-09 10:36:22 +01:00
Erik JohnstonandGitHub e5d07bb083 Fix bump stamp for non-joined rooms (#17674)
We should only look for bump stamps in joined rooms, otherwise we should
just use the membership stream ordering.
2024-09-06 11:44:37 +01:00
Erik JohnstonandGitHub a708e1afd0 Small performance improvements for sliding sync (#17672)
A couple of small performance improvements for sliding sync.
2024-09-06 11:44:13 +01:00
Erik Johnston 6b770d8bfc Revert "Fix bump stamp for non-joined rooms"
This reverts commit f73c844403.
2024-09-05 15:43:37 +01:00
Erik Johnston f73c844403 Fix bump stamp for non-joined rooms
We should only look for bump stamps in joined rooms, otherwise we should
just use the membership stream ordering.
2024-09-05 15:42:49 +01:00
Quentin GliechandGitHub 7d52ce7d4b Format files with Ruff (#17643)
I thought ruff check would also format, but it doesn't.

This runs ruff format in CI and dev scripts. The first commit is just a
run of `ruff format .` in the root directory.
2024-09-02 12:39:04 +01:00
709b7363fe Sliding sync: use new DB tables (#17630)
Based on https://github.com/element-hq/synapse/pull/17629

Utilizing the new sliding sync tables added in
https://github.com/element-hq/synapse/pull/17512 for fast acquisition of
rooms for the user and filtering/sorting.

---------

Co-authored-by: Eric Eastwood <eric.eastwood@beta.gouv.fr>
2024-09-01 11:25:39 +01:00
e43c2b023e Sliding sync: Store the per-connection state in the database. (#17599)
Based on #17600

---------

Co-authored-by: Eric Eastwood <eric.eastwood@beta.gouv.fr>
2024-08-29 16:26:58 +01:00
1a6b718f8c Sliding Sync: Pre-populate room data for quick filtering/sorting (#17512)
Pre-populate room data for quick filtering/sorting in the Sliding Sync
API

Spawning from
https://github.com/element-hq/synapse/pull/17450#discussion_r1697335578

This PR is acting as the Synapse version `N+1` step in the gradual
migration being tracked by
https://github.com/element-hq/synapse/issues/17623

Adding two new database tables:

- `sliding_sync_joined_rooms`: A table for storing room meta data that
the local server is still participating in. The info here can be shared
across all `Membership.JOIN`. Keyed on `(room_id)` and updated when the
relevant room current state changes or a new event is sent in the room.
- `sliding_sync_membership_snapshots`: A table for storing a snapshot of
room meta data at the time of the local user's membership. Keyed on
`(room_id, user_id)` and only updated when a user's membership in a room
changes.

Also adds background updates to populate these tables with all of the
existing data.


We want to have the guarantee that if a row exists in the sliding sync
tables, we are able to rely on it (accurate data). And if a row doesn't
exist, we use a fallback to get the same info until the background
updates fill in the rows or a new event comes in triggering it to be
fully inserted. This means we need a couple extra things in place until
we bump `SCHEMA_COMPAT_VERSION` and run the foreground update in the
`N+2` part of the gradual migration. For context on why we can't rely on
the tables without these things see [1].

1. On start-up, block until we clear out any rows for the rooms that
have had events since the max-`stream_ordering` of the
`sliding_sync_joined_rooms` table (compare to max-`stream_ordering` of
the `events` table). For `sliding_sync_membership_snapshots`, we can
compare to the max-`stream_ordering` of `local_current_membership`
- This accounts for when someone downgrades their Synapse version and
then upgrades it again. This will ensure that we don't have any
stale/out-of-date data in the
`sliding_sync_joined_rooms`/`sliding_sync_membership_snapshots` tables
since any new events sent in rooms would have also needed to be written
to the sliding sync tables. For example a new event needs to bump
`event_stream_ordering` in `sliding_sync_joined_rooms` table or some
state in the room changing (like the room name). Or another example of
someone's membership changing in a room affecting
`sliding_sync_membership_snapshots`.
1. Add another background update that will catch-up with any rows that
were just deleted from the sliding sync tables (based on the activity in
the `events`/`local_current_membership`). The rooms that need
recalculating are added to the
`sliding_sync_joined_rooms_to_recalculate` table.
1. Making sure rows are fully inserted. Instead of partially inserting,
we need to check if the row already exists and fully insert all data if
not.

All of this extra functionality can be removed once the
`SCHEMA_COMPAT_VERSION` is bumped with support for the new sliding sync
tables so people can no longer downgrade (the `N+2` part of the gradual
migration).


<details>
<summary><sup>[1]</sup></summary>

For `sliding_sync_joined_rooms`, since we partially insert rows as state
comes in, we can't rely on the existence of the row for a given
`room_id`. We can't even rely on looking at whether the background
update has finished. There could still be partial rows from when someone
reverted their Synapse version after the background update finished, had
some state changes (or new rooms), then upgraded again and more state
changes happen leaving a partial row.

For `sliding_sync_membership_snapshots`, we insert items as a whole
except for the `forgotten` column ~~so we can rely on rows existing and
just need to always use a fallback for the `forgotten` data. We can't
use the `forgotten` column in the table for the same reasons above about
`sliding_sync_joined_rooms`.~~ We could have an out-of-date membership
from when someone reverted their Synapse version. (same problems as
outlined for `sliding_sync_joined_rooms` above)

Discussed in an [internal
meeting](https://docs.google.com/document/d/1MnuvPkaCkT_wviSQZ6YKBjiWciCBFMd-7hxyCO-OCbQ/edit#bookmark=id.dz5x6ef4mxz7)

</details>


### TODO

 - [x] Update `stream_ordering`/`bump_stamp`
 - [x] Handle remote invites
 - [x] Handle state resets
- [x] Consider adding `sender` so we can filter `LEAVE` memberships and
distinguish from kicks.
     - [x] We should add it to be able to tell leaves from kicks 
- [x] Consider adding `tombstone` state to help address
https://github.com/element-hq/synapse/issues/17540
     - [x] We should add it `tombstone_successor_room_id`
- [x] Consider adding `forgotten` status to avoid extra
lookup/table-join on `room_memberships`
    - [x] We should add it
- [x] Background update to fill in values for all joined rooms and
non-join membership
 - [x] Clean-up tables when room is deleted
 - [ ] Make sure tables are useful to our use case
- First explored in
https://github.com/element-hq/synapse/compare/erikj/ss_use_new_tables
- Also explored in
https://github.com/element-hq/synapse/commit/76b5a576eb363496315dfd39510cad7d02b0fc73
 - [x] Plan for how can we use this with a fallback
     - See plan discussed above in main area of the issue description
- Discussed in an [internal
meeting](https://docs.google.com/document/d/1MnuvPkaCkT_wviSQZ6YKBjiWciCBFMd-7hxyCO-OCbQ/edit#bookmark=id.dz5x6ef4mxz7)
 - [x] Plan for how we can rely on this new table without a fallback
- Synapse version `N+1`: (this PR) Bump `SCHEMA_VERSION` to `87`. Add
new tables and background update to backfill all rows. Since this is a
new table, we don't have to add any `NOT VALID` constraints and validate
them when the background update completes. Read from new tables with a
fallback in cases where the rows aren't filled in yet.
- Synapse version `N+2`: Bump `SCHEMA_VERSION` to `88` and bump
`SCHEMA_COMPAT_VERSION` to `87` because we don't want people to
downgrade and miss writes while they are on an older version. Add a
foreground update to finish off the backfill so we can read from new
tables without the fallback. Application code can now rely on the new
tables being populated.
- Discussed in an [internal
meeting](https://docs.google.com/document/d/1MnuvPkaCkT_wviSQZ6YKBjiWciCBFMd-7hxyCO-OCbQ/edit#bookmark=id.hh7shg4cxdhj)




### Dev notes

```
SYNAPSE_TEST_LOG_LEVEL=INFO poetry run trial tests.storage.test_events.SlidingSyncPrePopulatedTablesTestCase

SYNAPSE_POSTGRES=1 SYNAPSE_POSTGRES_USER=postgres SYNAPSE_TEST_LOG_LEVEL=INFO poetry run trial tests.storage.test_events.SlidingSyncPrePopulatedTablesTestCase
```

```
SYNAPSE_TEST_LOG_LEVEL=INFO poetry run trial tests.handlers.test_sliding_sync.FilterRoomsTestCase
```

Reference:

- [Development docs on background updates and worked examples of gradual
migrations

](https://github.com/element-hq/synapse/blob/1dfa59b238cee0dc62163588cc9481896c288979/docs/development/database_schema.md#background-updates)
- A real example of a gradual migration:
https://github.com/matrix-org/synapse/pull/15649#discussion_r1213779514
- Adding `rooms.creator` field that needed a background update to
backfill data, https://github.com/matrix-org/synapse/pull/10697
- Adding `rooms.room_version` that needed a background update to
backfill data, https://github.com/matrix-org/synapse/pull/6729
- Adding `room_stats_state.room_type` that needed a background update to
backfill data, https://github.com/matrix-org/synapse/pull/13031
- Tables from MSC2716: `insertion_events`, `insertion_event_edges`,
`insertion_event_extremities`, `batch_events`
- `current_state_events` updated in
`synapse/storage/databases/main/events.py`

---

```
persist_event (adds to queue)
_persist_event_batch
_persist_events_and_state_updates (assigns `stream_ordering` to events)
_persist_events_txn
	_store_event_txn
        _update_metadata_tables_txn
            _store_room_members_txn
	_update_current_state_txn
```

---

> Concatenated Indexes [...] (also known as multi-column, composite or
combined index)
>
> [...] key consists of multiple columns.
> 
> We can take advantage of the fact that the first index column is
always usable for searching
>
> *--
https://use-the-index-luke.com/sql/where-clause/the-equals-operator/concatenated-keys*

---

Dealing with `portdb` (`synapse/_scripts/synapse_port_db.py`),
https://github.com/element-hq/synapse/pull/17512#discussion_r1725998219

---

<details>
<summary>SQL queries:</summary>

Both of these are equivalent and work in SQLite and Postgres

Options 1:
```sql
WITH data_table (room_id, user_id, membership_event_id, membership, event_stream_ordering, {", ".join(insert_keys)}) AS (
    VALUES (
        ?, ?, ?,
        (SELECT membership FROM room_memberships WHERE event_id = ?),
        (SELECT stream_ordering FROM events WHERE event_id = ?),
        {", ".join("?" for _ in insert_values)}
    )
)
INSERT INTO sliding_sync_non_join_memberships
    (room_id, user_id, membership_event_id, membership, event_stream_ordering, {", ".join(insert_keys)})
SELECT * FROM data_table
WHERE membership != ?
ON CONFLICT (room_id, user_id)
DO UPDATE SET
    membership_event_id = EXCLUDED.membership_event_id,
    membership = EXCLUDED.membership,
    event_stream_ordering = EXCLUDED.event_stream_ordering,
    {", ".join(f"{key} = EXCLUDED.{key}" for key in insert_keys)}
```

Option 2:
```sql
INSERT INTO sliding_sync_non_join_memberships
    (room_id, user_id, membership_event_id, membership, event_stream_ordering, {", ".join(insert_keys)})
SELECT 
    column1 as room_id,
    column2 as user_id,
    column3 as membership_event_id,
    column4 as membership,
    column5 as event_stream_ordering,
    {", ".join("column" + str(i) for i in range(6, 6 + len(insert_keys)))}
FROM (
    VALUES (
        ?, ?, ?,
        (SELECT membership FROM room_memberships WHERE event_id = ?),
        (SELECT stream_ordering FROM events WHERE event_id = ?),
        {", ".join("?" for _ in insert_values)}
    )
) as v
WHERE membership != ?
ON CONFLICT (room_id, user_id)
DO UPDATE SET
    membership_event_id = EXCLUDED.membership_event_id,
    membership = EXCLUDED.membership,
    event_stream_ordering = EXCLUDED.event_stream_ordering,
    {", ".join(f"{key} = EXCLUDED.{key}" for key in insert_keys)}
```

If we don't need the `membership` condition, we could use:

```sql
INSERT INTO sliding_sync_non_join_memberships
    (room_id, membership_event_id, user_id, membership, event_stream_ordering, {", ".join(insert_keys)})
VALUES (
    ?, ?, ?,
    (SELECT membership FROM room_memberships WHERE event_id = ?),
    (SELECT stream_ordering FROM events WHERE event_id = ?),
    {", ".join("?" for _ in insert_values)}
)
ON CONFLICT (room_id, user_id)
DO UPDATE SET
    membership_event_id = EXCLUDED.membership_event_id,
    membership = EXCLUDED.membership,
    event_stream_ordering = EXCLUDED.event_stream_ordering,
    {", ".join(f"{key} = EXCLUDED.{key}" for key in insert_keys)}
```

</details>

### Pull Request Checklist

<!-- Please read
https://element-hq.github.io/synapse/latest/development/contributing_guide.html
before submitting your pull request -->

* [x] Pull request is based on the develop branch
* [x] Pull request includes a [changelog
file](https://element-hq.github.io/synapse/latest/development/contributing_guide.html#changelog).
The entry should:
- Be a short description of your change which makes sense to users.
"Fixed a bug that prevented receiving messages from other servers."
instead of "Moved X method from `EventStore` to `EventWorkerStore`.".
  - Use markdown where necessary, mostly for `code blocks`.
  - End with either a period (.) or an exclamation mark (!).
  - Start with a capital letter.
- Feel free to credit yourself, by adding a sentence "Contributed by
@github_username." or "Contributed by [Your Name]." to the end of the
entry.
* [x] [Code
style](https://element-hq.github.io/synapse/latest/code_style.html) is
correct
(run the
[linters](https://element-hq.github.io/synapse/latest/development/contributing_guide.html#run-the-linters))

---------

Co-authored-by: Erik Johnston <erik@matrix.org>
2024-08-29 16:09:51 +01:00