Ensure that the list of servers in a partial state room always contains
the server we joined off.
Also refactor `get_partial_state_servers_at_join` to return `None` when
the given room is no longer partial stated, to explicitly indicate when
the room has partial state. Otherwise it's not clear whether an empty
list means that the room has full state, or the room is partial stated,
but the server we joined off told us that there are no servers in the
room.
Signed-off-by: Sean Quah <seanq@matrix.org>
If a sync request does not need to calculate per-room entries &
is not generating presence & is not generating device list data
(e.g. during initial sync) avoid the expensive calculation of room
specific data.
This is a micro-optimisation for clients syncing simply to receive
to-device information.
This expands the previous optimisation from being only for initial
sync to being for all sync requests.
It also inverts some of the logic to be inclusive instead of exclusive.
The `parse_enum` helper pulls an enum value from the query string
(by delegating down to the parse_string helper with values generated
from the enum).
This is used to pull out "f" and "b" in most places and then we thread
the resulting Direction enum throughout more code.
`run_in_background` calls re-use the current logging context. When they
are not awaited, they can complete after the current logging context has
been marked as finished, which leads to log spam. Use
`run_as_background_process` instead.
Fixes one of the instances of #13090.
Signed-off-by: Sean Quah <seanq@matrix.org>
* Perfer `type(x) is int` to `isinstance(x, int)`
This covered all additional instances I could see where `x` was
user-controlled.
The remaining cases are
```
$ rg -s 'isinstance.*[^_]int'
tests/replication/_base.py
576: if isinstance(obj, int):
synapse/util/caches/stream_change_cache.py
136: assert isinstance(stream_pos, int)
214: assert isinstance(stream_pos, int)
246: assert isinstance(stream_pos, int)
267: assert isinstance(stream_pos, int)
synapse/replication/tcp/external_cache.py
133: if isinstance(result, int):
synapse/metrics/__init__.py
100: if isinstance(calls, (int, float)):
synapse/handlers/appservice.py
262: assert isinstance(new_token, int)
synapse/config/_util.py
62: if isinstance(p, int):
```
which cover metrics, logic related to `jsonschema`, and replication and
data streams. AFAICS these are all internal to Synapse
* Changelog
* Batch look-ups to see if rooms are partial stated.
* Fix issues found in linting.
* Fix typo.
* Apply suggestions from code review
Co-authored-by: Sean Quah <8349537+squahtx@users.noreply.github.com>
* Clarify comments.
Co-authored-by: Sean Quah <8349537+squahtx@users.noreply.github.com>
* Also improve the cache size while we're at it
* is_partial_state_rooms -> is_partial_state_room_batched
* Run `black`
* Improve annotation for `simple_select_many_batch`
* Fix is_partial_state_room_batched impl
* Okay, _actually_ fix impl
* Update description.
* Update synapse/storage/databases/main/room.py
Co-authored-by: Patrick Cloke <clokep@users.noreply.github.com>
* Run black.
Co-authored-by: Sean Quah <8349537+squahtx@users.noreply.github.com>
Co-authored-by: David Robertson <davidr@element.io>
Destination was being used incorrectly (a single destination instead
of a list of destinations was being passed).
This also updates some of the types in the area to not use Collection[str],
which is a footgun.
* Allow `AbstractSet` in `StrCollection`
Or else frozensets are excluded. This will be useful in an upcoming
commit where I plan to change a function that accepts `List[str]` to
accept `StrCollection` instead.
* `rooms_to_exclude` -> `rooms_to_exclude_globally`
I am about to make use of this exclusion mechanism to exclude rooms for
a specific user and a specific sync. This rename helps to clarify the
distinction between the global config and the rooms to exclude for a
specific sync.
* Better function names for internal sync methods
* Track a list of excluded rooms on SyncResultBuilder
I plan to feed a list of partially stated rooms for this sync to ignore
* Exclude partial state rooms during eager sync
using the mechanism established in the previous commit
* Track un-partial-state stream in sync tokens
So that we can work out which rooms have become fully-stated during a
given sync period.
* Fix mutation of `@cached` return value
This was fouling up a complement test added alongside this PR.
Excluding a room would mean the set of forgotten rooms in the cache
would be extended. This means that room could be erroneously considered
forgotten in the future.
Introduced in #12310, Synapse 1.57.0. I don't think this had any
user-visible side effects (until now).
* SyncResultBuilder: track rooms to force as newly joined
Similar plan as before. We've omitted rooms from certain sync responses;
now we establish the mechanism to reintroduce them into future syncs.
* Read new field, to present rooms as newly joined
* Force un-partial-stated rooms to be newly-joined
for eager incremental syncs only, provided they're still fully stated
* Notify user stream listeners to wake up long polling syncs
* Changelog
* Typo fix
Co-authored-by: Sean Quah <8349537+squahtx@users.noreply.github.com>
* Unnecessary list cast
Co-authored-by: Sean Quah <8349537+squahtx@users.noreply.github.com>
* Rephrase comment
Co-authored-by: Sean Quah <8349537+squahtx@users.noreply.github.com>
* Another comment
Co-authored-by: Sean Quah <8349537+squahtx@users.noreply.github.com>
* Fixup merge(?)
* Poke notifier when receiving un-partial-stated msg over replication
* Fixup merge whoops
Thanks MV :)
Co-authored-by: Mathieu Velen <mathieuv@matrix.org>
Co-authored-by: Mathieu Velten <mathieuv@matrix.org>
Co-authored-by: Sean Quah <8349537+squahtx@users.noreply.github.com>
* Faster joins: Update room stats and user directory on workers when done
When finishing a partial state join to a room, we update the current
state of the room without persisting additional events. Workers receive
notice of the current state update over replication, but neglect to wake
the room stats and user directory updaters, which then get incidentally
triggered the next time an event is persisted or an unrelated event
persister sends out a stream position update.
We wake the room stats and user directory updaters at the appropriate
time in this commit.
Part of #12814 and #12815.
Signed-off-by: Sean Quah <seanq@matrix.org>
* fixup comment
Signed-off-by: Sean Quah <seanq@matrix.org>
* Enable Complement tests for Faster Remote Room Joins on worker-mode
* (dangerous) Add an override to allow Complement to use FRRJ under workers
* Newsfile
Signed-off-by: Olivier Wilkinson (reivilibre) <oliverw@matrix.org>
* Fix race where we didn't send out replication notification
* MORE HACKS
* Fix get_un_partial_stated_rooms_token to take instance_name
* Fix bad merge
* Remove warning
* Correctly advance un_partial_stated_room_stream
* Fix merge
* Add another notify_replication
* Fixups
* Create a separate ReplicationNotifier
* Fix test
* Fix portdb
* Create a separate ReplicationNotifier
* Fix test
* Fix portdb
* Fix presence test
* Newsfile
* Apply suggestions from code review
* Update changelog.d/14752.misc
Co-authored-by: Erik Johnston <erik@matrix.org>
* lint
Signed-off-by: Olivier Wilkinson (reivilibre) <oliverw@matrix.org>
Co-authored-by: Erik Johnston <erik@matrix.org>
* Avoid clearing out forward extremities when doing a second remote join
When joining a restricted room where the local homeserver does not have
a user able to issue invites, we perform a second remote join. We want
to avoid clearing out forward extremities in this case because the
forward extremities we have are up to date and clearing out forward
extremities creates a window in which the room can get bricked if
Synapse crashes.
Signed-off-by: Sean Quah <seanq@matrix.org>
* Do a full join when doing a second remote join into a full state room
We cannot persist a partial state join event into a joined full state
room, so we perform a full state join for such rooms instead. As a
future optimization, we could always perform a partial state join and
compute or retrieve the full state ourselves if necessary.
Signed-off-by: Sean Quah <seanq@matrix.org>
* Add lock around partial state flag for rooms
Signed-off-by: Sean Quah <seanq@matrix.org>
* Preserve partial state info when doing a second partial state join
Signed-off-by: Sean Quah <seanq@matrix.org>
* Add newsfile
* Add a TODO(faster_joins) marker
Signed-off-by: Sean Quah <seanq@matrix.org>
Currently, we will try to start a new partial state sync every time we
perform a remote join, which is undesirable if there is already one
running for a given room.
We intend to perform remote joins whenever additional local users wish
to join a partial state room, so let's ensure that we do not start more
than one concurrent partial state sync for any given room.
------------------------------------------------------------------------
There is a race condition where the homeserver leaves a room and later
rejoins while the partial state sync from the previous membership is
still running. There is no guarantee that the previous partial state
sync will process the latest join, so we restart it if needed.
Signed-off-by: Sean Quah <seanq@matrix.org>
This has two related changes:
* It enables fast-path processing for an empty filter (`[]`) which was
previously only used for wildcard not-filters (`["*"]`).
* It special cases a `/sync` filter with no-rooms to skip all room
processing, previously we would partially skip processing, but would
generally still calculate intermediate values for each room which were
then unused.
Future changes might consider further optimizations:
* Skip calculating per-room account data when all rooms are filtered (currently
this is thrown away).
* Make similar improvements to other endpoints which support filters.
PKCE can protect against certain attacks and is enabled by default. Support
can be controlled manually by setting the pkce_method of each oidc_providers
entry to 'auto' (default), 'always', or 'never'.
This is required by Twitter OAuth 2.0 support.
OpenID specifies the format of the user info endpoint and some
OAuth 2.0 IdPs do not follow it, e.g. NextCloud and Twitter.
This adds subject_template and picture_template options to the
default mapping provider for more flexibility in matching those user
info responses.
Then adapts calling code to retry when needed so it doesn't 500
to clients.
Signed-off-by: Mathieu Velten <mathieuv@matrix.org>
Co-authored-by: Sean Quah <8349537+squahtx@users.noreply.github.com>
This avoids pulling additional state information (and events) from
the database for each item returned in the hierarchy response.
The room type might be out of date until a background update finishes
running, the worst impact of this would be spaces being treated as rooms
in the hierarchy response. This should self-heal once the background
update finishes.
* Declare new config
* Parse new config
* Read new config
* Don't use trial/our TestCase where it's not needed
Before:
```
$ time trial tests/events/test_utils.py > /dev/null
real 0m2.277s
user 0m2.186s
sys 0m0.083s
```
After:
```
$ time trial tests/events/test_utils.py > /dev/null
real 0m0.566s
user 0m0.508s
sys 0m0.056s
```
* Helper to upsert to event fields
without exceeding size limits.
* Use helper when adding invite/knock state
Now that we allow admins to include events in prejoin room state with
arbitrary state keys, be a good Matrix citizen and ensure they don't
accidentally create an oversized event.
* Changelog
* Move StateFilter tests
should have done this in #14668
* Add extra methods to StateFilter
* Use StateFilter
* Ensure test file enforces typed defs; alphabetise
* Workaround surprising get_current_state_ids
* Whoops, fix mypy
This should help reduce the number of devices e.g. simple bots the repeatedly login rack up.
We only delete non-e2e devices as they should be safe to delete, whereas if we delete e2e devices for a user we may accidentally break their ability to receive e2e keys for a message.
A batch of changes intended to make it easier to trace to-device messages through the system.
The intention here is that a client can set a property org.matrix.msgid in any to-device message it sends. That ID is then included in any tracing or logging related to the message. (Suggestions as to where this field should be documented welcome. I'm not enthusiastic about speccing it - it's very much an optional extra to help with debugging.)
I've also generally improved the data we send to opentracing for these messages.
StreamChangeCache.get_all_changed_entities can return None to signify
it does not have information at the given stream position. Two callers (related
to device lists and presence) were treating this response the same as an empty
list (i.e. there being no updates).
This should help reduce the number of devices e.g. simple bots the repeatedly login rack up.
We only delete non-e2e devices as they should be safe to delete, whereas if we delete e2e devices for a user we may accidentally break their ability to receive e2e keys for a message.
Co-authored-by: Patrick Cloke <clokep@users.noreply.github.com>
Co-authored-by: Sean Quah <8349537+squahtx@users.noreply.github.com>
* Use `device_one_time_keys_count` to match MSC3202
Rename the `device_one_time_key_counts` key in responses to
`device_one_time_keys_count` to match the name specified by MSC3202.
Also change related variable/class names for consistency.
Signed-off-by: Andrew Ferrazzutti <andrewf@element.io>
* Update changelog.d/14565.misc
* Revert name change for `one_time_key_counts` key
as this is a different key altogether from `device_one_time_keys_count`,
which is used for `/sync` instead of appservice transactions.
Signed-off-by: Andrew Ferrazzutti <andrewf@element.io>
Include the thread_id field when sending read receipts over
federation. This might result in the same user having multiple
read receipts per-room, meaning multiple EDUs must be sent
to encapsulate those receipts.
This restructures the PerDestinationQueue APIs to support
multiple receipt EDUs, queue_read_receipt now becomes linear
time in the number of queued threaded receipts in the room for
the given user, it is expected this is a small number since receipt
EDUs are sent as filler in transactions.
This commit adds support for handling a provided avatar picture URL
when logging in via SSO.
Signed-off-by: Ashish Kumar <ashfame@users.noreply.github.com>
Fixes#9357.
This was the last untyped handler from the HomeServer object. Since
it was being treated as Any (and thus unchecked) it was being used
incorrectly in a few places.
When a local device list change is added to
`device_lists_changes_in_room`, the `converted_to_destinations` flag is
set to `FALSE` and the `_handle_new_device_update_async` background
process is started. This background process looks for unconverted rows
in `device_lists_changes_in_room`, copies them to
`device_lists_outbound_pokes` and updates the flag.
To update the `converted_to_destinations` flag, the database performs a
`DELETE` and `INSERT` internally, which fragments the table. To avoid
this, track unconverted rows using a `(stream ID, room ID)` position
instead of the flag.
From now on, the `converted_to_destinations` column indicates rows that
need converting to outbound pokes, but does not indicate whether the
conversion has already taken place.
Closes#14037.
Signed-off-by: Sean Quah <seanq@matrix.org>
Avoid an n+1 query problem and fetch the bundled aggregations for
m.reference relations in a single query instead of a query per event.
This applies similar logic for as was previously done for edits in
8b309adb43 (#11660; threads
in b65acead42 (#11752); and
annotations in 1799a54a54 (#14491).
Avoid an n+1 query problem and fetch the bundled aggregations for
m.annotation relations in a single query instead of a query per event.
This applies similar logic for as was previously done for edits in
8b309adb43 (#11660) and threads
in b65acead42 (#11752).
Remove type hints from comments which have been added
as Python type hints. This helps avoid drift between comments
and reality, as well as removing redundant information.
Also adds some missing type hints which were simple to fill in.
We don't filter state usually, so doing so here is a waste of time. This is not much of an issue for clients that enable lazy loading of members, since there will be fewer state events.
If configured an OIDC IdP can log a user's session out of
Synapse when they log out of the identity provider.
The IdP sends a request directly to Synapse (and must be
configured with an endpoint) when a user logs out.
* Introduce a test for the old behaviour which we want to restore
* Reintroduce the old behaviour in a simpler way
* Newsfile
Signed-off-by: Olivier Wilkinson (reivilibre) <oliverw@matrix.org>
* Use 1 credit instead of 2 for creating a room: be more lenient than before
Notably, the UI in Element Web was still broken after restoring to prior behaviour.
After discussion, we agreed that it would be sensible to increase the limit.
Signed-off-by: Olivier Wilkinson (reivilibre) <oliverw@matrix.org>
1. `federation_client.timestamp_to_event(...)` now handles all `destination` looping and uses our generic `_try_destination_list(...)` helper.
2. Consistently handling `NotRetryingDestination` and `FederationDeniedError` across `get_pdu` , backfill, and the generic `_try_destination_list` which is used for many places we use this pattern.
3. `get_pdu(...)` now returns `PulledPduInfo` so we know which `destination` we ended up pulling the PDU from
Fixes check_avatar_size_and_mime_type() to successfully update avatars on homeservers running on non-default ports which it would mistakenly treat as remote homeserver while validating the avatar's size and mime type.
Signed-off-by: Ashish Kumar ashfame@users.noreply.github.com
This implements a fake OIDC server, which intercepts calls to the HTTP client.
Improves accuracy of tests by covering more internal methods.
One particular example was the ID token validation, which previously mocked.
This uncovered an incorrect dependency: Synapse actually requires at least
authlib 0.15.1, not 0.14.0.
* Show erasure status when listing users in the Admin API
* Use USING when joining erased_users
* Add changelog entry
* Revert "Use USING when joining erased_users"
This reverts commit 30bd2bf106.
* Make the erased check work on postgres
* Add a testcase for showing erased user status
* Appease the style linter
* Explicitly convert `erased` to bool to make SQLite consistent with Postgres
This also adds us an easy way in to fix the other accidentally integered columns.
* Move erasure status test to UsersListTestCase
* Include user erased status when fetching user info via the admin API
* Document the erase status in user_admin_api
* Appease the linter and mypy
* Signpost comments in tests
Co-authored-by: Tadeusz Sośnierz <tadeusz@sosnierz.com>
Co-authored-by: David Robertson <david.m.robertson1@gmail.com>
While https://github.com/matrix-org/synapse/pull/13635 stops us from doing the slow thing after we've already done it once, this PR stops us from doing one of the slow things in the first place.
Related to
- https://github.com/matrix-org/synapse/issues/13622
- https://github.com/matrix-org/synapse/pull/13635
- https://github.com/matrix-org/synapse/issues/13676
Part of https://github.com/matrix-org/synapse/issues/13356
Follow-up to https://github.com/matrix-org/synapse/pull/13815 which tracks event signature failures.
With this PR, we avoid the call to the costly `_get_state_ids_after_missing_prev_event` because the signature failure will count as an attempt before and we filter events based on the backoff before calling `_get_state_ids_after_missing_prev_event` now.
For example, this will save us 156s out of the 185s total that this `matrix.org` `/messages` request. If you want to see the full Jaeger trace of this, you can drag and drop this `trace.json` into your own Jaeger, https://gist.github.com/MadLittleMods/4b12d0d0afe88c2f65ffcc907306b761
To explain this exact scenario around `/messages` -> backfill, we call `/backfill` and first check the signatures of the 100 events. We see bad signature for `$luA4l7QHhf_jadH3mI-AyFqho0U2Q-IXXUbGSMq6h6M` and `$zuOn2Rd2vsC7SUia3Hp3r6JSkSFKcc5j3QTTqW_0jDw` (both member events). Then we process the 98 events remaining that have valid signatures but one of the events references `$luA4l7QHhf_jadH3mI-AyFqho0U2Q-IXXUbGSMq6h6M` as a `prev_event`. So we have to do the whole `_get_state_ids_after_missing_prev_event` rigmarole which pulls in those same events which fail again because the signatures are still invalid.
- `backfill`
- `outgoing-federation-request` `/backfill`
- `_check_sigs_and_hash_and_fetch`
- `_check_sigs_and_hash_and_fetch_one` for each event received over backfill
- ❗ `$luA4l7QHhf_jadH3mI-AyFqho0U2Q-IXXUbGSMq6h6M` fails with `Signature on retrieved event was invalid.`: `unable to verify signature for sender domain xxx: 401: Failed to find any key to satisfy: _FetchKeyRequest(...)`
- ❗ `$zuOn2Rd2vsC7SUia3Hp3r6JSkSFKcc5j3QTTqW_0jDw` fails with `Signature on retrieved event was invalid.`: `unable to verify signature for sender domain xxx: 401: Failed to find any key to satisfy: _FetchKeyRequest(...)`
- `_process_pulled_events`
- `_process_pulled_event` for each validated event
- ❗ Event `$Q0iMdqtz3IJYfZQU2Xk2WjB5NDF8Gg8cFSYYyKQgKJ0` references `$luA4l7QHhf_jadH3mI-AyFqho0U2Q-IXXUbGSMq6h6M` as a `prev_event` which is missing so we try to get it
- `_get_state_ids_after_missing_prev_event`
- `outgoing-federation-request` `/state_ids`
- ❗ `get_pdu` for `$luA4l7QHhf_jadH3mI-AyFqho0U2Q-IXXUbGSMq6h6M` which fails the signature check again
- ❗ `get_pdu` for `$zuOn2Rd2vsC7SUia3Hp3r6JSkSFKcc5j3QTTqW_0jDw` which fails the signature check
The callers either set a default limit or manually handle a None-limit
later on (by setting a default value).
Update the callers to always instantiate PaginationConfig with a default
limit and then assume the limit is non-None.
Implement the /threads endpoint from MSC3856.
This is currently unstable and behind an experimental configuration
flag.
It includes a background update to backfill data, results from
the /threads endpoint will be partial until that finishes.
By getting the joined rooms before the current token we avoid any reading
history to confirm a user *was* in a room. We can then use any membership
change events, which we already fetch during sync, to determine the final
list of joined room IDs.
When retrieving counts of notifications segment the results based on the
thread ID, but choose whether to return them as individual threads or as
a single summed field by letting the client opt-in via a sync flag.
The summarization code is also updated to be per thread, instead of per
room.
Keep the old behavior (of including the original_event field) for any
requests to the /unstable version of the endpoint, but do not include
the field when the /v1 version is used.
This should avoid new clients from depending on this field, but will
not help with current dependencies.
MSC3316 declares that both /rooms/{roomId}/send and /rooms/{roomId}/state
should accept a ts parameter for appservices. This change expands support
to /state and adds tests.
Spawned while working on [`get_users_in_room` mis-uses](https://github.com/matrix-org/synapse/pull/13958#discussion_r984074897) and thinking we could use `get_local_users_in_room` here but we can't.
From first glance, it seemed like this was only using local users from all of the `is_mine_id(user_id)` checks but I see that it does actually use remote users. Just making things a little more clear here what it does and mentions remote users so maybe that will be more obvious in the future.
Fixes#13942. Introduced in #13575.
Basically, let's only get the ordered set of hosts out of the DB if we need an ordered set of hosts. Since we split the function up the caching won't be as good, but I think it will still be fine as e.g. multiple backfill requests for the same room will hit the cache.
There is no need to grab thousands of backfill points when we only need 5 to make the `/backfill` request with. We need to grab a few extra in case the first few aren't visible in the history.
Previously, we grabbed thousands of backfill points from the database, then sorted and filtered them in the app. Fetching the 4.6k backfill points for `#matrix:matrix.org` from the database takes ~50ms - ~570ms so it's not like this saves a lot of time 🤷. But it might save us more time now that `get_backfill_points_in_room`/`get_insertion_event_backward_extremities_in_room` are more complicated after https://github.com/matrix-org/synapse/pull/13635
This PR moves the filtering and limiting to the SQL query so we just have less data to work with in the first place.
Part of https://github.com/matrix-org/synapse/issues/13356
c.f. #12993 (comment), point 3
This stores all device list updates that we receive while partial joins are ongoing, and processes them once we have the full state.
Note: We don't actually process the device lists in the same ways as if we weren't partially joined. Instead of updating the device list remote cache, we simply notify local users that a change in the remote user's devices has happened. I think this is safe as if the local user requests the keys for the remote user and we don't have them we'll simply fetch them as normal.
This PR begins work on batching up events during the creation of a room. The PR splits out the creation and sending/persisting of the events. The first three events in the creation of the room-creating the room, joining the creator to the room, and the power levels event are sent sequentially, while the subsequent events are created and collected to be sent at the end of the function. This is currently done by appending them to a list and then iterating over the list to send, the next step (after this PR) would be to send and persist the collected events as a batch.
Since #11482, we're saving sessions IDs from upstream IdPs, but we've been losing them when the user goes through a user mapping session on account registration.
During a `lazy_load_members` `/sync`, we look through auth events in
rooms with partial state to find prior membership events. When such a
membership is not found, an error is logged.
Since the first join event for a user never has a prior membership event
to cite, the error would always be logged when one appeared in the room
timeline.
Avoid logging errors for such events.
Introduced in #13477.
Signed-off-by: Sean Quah <seanq@matrix.org>
This is also using the partial state approximation if needed so we do
not block here during a fast join.
Signed-off-by: Mathieu Velten <mathieuv@matrix.org>
Co-authored-by: Sean Quah <8349537+squahtx@users.noreply.github.com>
Part of the work for #12993.
Once #12993 is fully resolved, we expect `/keys/changes` to behave
sensibly when joined to a room with partial state.
Signed-off-by: Sean Quah <seanq@matrix.org>
Use the provided list of servers in the room from the `/send_join`
response, since we will not know which users are in the room. This
isn't sufficient to ensure that all remote servers receive the right
device list updates, since the `/send_join` response may be inaccurate
or we may calculate the membership state of new users in the room
incorrectly.
Signed-off-by: Sean Quah <seanq@matrix.org>
When a remote user leaves the last room shared with the homeserver, we
have to mark their device list as unsubscribed, otherwise we would hold
on to a stale device list in our cache. Crucially, the device list would
remain cached even after the remote user rejoined the room, which could
lead to E2EE failures until the next change to the remote user's device
list.
Fixes#13651.
Signed-off-by: Sean Quah <seanq@matrix.org>
This is a re-do of 57d334a13d (#13365),
which was backed out in 12abd72497 (#13501).
The `room_id` field represented the parent space for each room
and was made redundant by changes in the API shape where the
`children_state` is now nested underneath each `room`.
The room ID of each child is in the `state_key` field and is still
available.
Optimize how we calculate `likely_domains` during backfill because I've seen this take 17s in production just to `get_current_state` which is used to `get_domains_from_state` (see case [*2. Loading tons of events* in the `/messages` investigation issue](https://github.com/matrix-org/synapse/issues/13356)).
There are 3 ways we currently calculate hosts that are in the room:
1. `get_current_state` -> `get_domains_from_state`
- Used in `backfill` to calculate `likely_domains` and `/timestamp_to_event` because it was cargo-culted from `backfill`
- This one is being eliminated in favor of `get_current_hosts_in_room` in this PR 🕳
1. `get_current_hosts_in_room`
- Used for other federation things like sending read receipts and typing indicators
1. `get_hosts_in_room_at_events`
- Used when pushing out events over federation to other servers in the `_process_event_queue_loop`
Fix https://github.com/matrix-org/synapse/issues/13626
Part of https://github.com/matrix-org/synapse/issues/13356
Mentioned in [internal doc](https://docs.google.com/document/d/1lvUoVfYUiy6UaHB6Rb4HicjaJAU40-APue9Q4vzuW3c/edit#bookmark=id.2tvwz3yhcafh)
### Query performance
#### Before
The query from `get_current_state` sucks just because we have to get all 80k events. And we see almost the exact same performance locally trying to get all of these events (16s vs 17s):
```
synapse=# SELECT type, state_key, event_id FROM current_state_events WHERE room_id = '!OGEhHVWSdvArJzumhm:matrix.org';
Time: 16035.612 ms (00:16.036)
synapse=# SELECT type, state_key, event_id FROM current_state_events WHERE room_id = '!OGEhHVWSdvArJzumhm:matrix.org';
Time: 4243.237 ms (00:04.243)
```
But what about `get_current_hosts_in_room`: When there is 8M rows in the `current_state_events` table, the previous query in `get_current_hosts_in_room` took 13s from complete freshness (when the events were first added). But takes 930ms after a Postgres restart or 390ms if running back to back to back.
```sh
$ psql synapse
synapse=# \timing on
synapse=# SELECT COUNT(DISTINCT substring(state_key FROM '@[^:]*:(.*)$'))
FROM current_state_events
WHERE
type = 'm.room.member'
AND membership = 'join'
AND room_id = '!OGEhHVWSdvArJzumhm:matrix.org';
count
-------
4130
(1 row)
Time: 13181.598 ms (00:13.182)
synapse=# SELECT COUNT(*) from current_state_events where room_id = '!OGEhHVWSdvArJzumhm:matrix.org';
count
-------
80814
synapse=# SELECT COUNT(*) from current_state_events;
count
---------
8162847
synapse=# SELECT pg_size_pretty( pg_total_relation_size('current_state_events') );
pg_size_pretty
----------------
4702 MB
```
#### After
I'm not sure how long it takes from complete freshness as I only really get that opportunity once (maybe restarting computer but that's cumbersome) and it's not really relevant to normal operating times. Maybe you get closer to the fresh times the more access variability there is so that Postgres caches aren't as exact. Update: The longest I've seen this run for is 6.4s and 4.5s after a computer restart.
After a Postgres restart, it takes 330ms and running back to back takes 260ms.
```sh
$ psql synapse
synapse=# \timing on
Timing is on.
synapse=# SELECT
substring(c.state_key FROM '@[^:]*:(.*)$') as host
FROM current_state_events c
/* Get the depth of the event from the events table */
INNER JOIN events AS e USING (event_id)
WHERE
c.type = 'm.room.member'
AND c.membership = 'join'
AND c.room_id = '!OGEhHVWSdvArJzumhm:matrix.org'
GROUP BY host
ORDER BY min(e.depth) ASC;
Time: 333.800 ms
```
#### Going further
To improve things further we could add a `limit` parameter to `get_current_hosts_in_room`. Realistically, we don't need 4k domains to choose from because there is no way we're going to query that many before we a) probably get an answer or b) we give up.
Another thing we can do is optimize the query to use a index skip scan:
- https://wiki.postgresql.org/wiki/Loose_indexscan
- Index Skip Scan, https://commitfest.postgresql.org/37/1741/
- https://www.timescale.com/blog/how-we-made-distinct-queries-up-to-8000x-faster-on-postgresql/
Use dedicated `get_local_users_in_room` to find local users when calculating `join_authorised_via_users_server` ("the authorising user for joining a restricted room") of a `/make_join` request.
Found while working on https://github.com/matrix-org/synapse/pull/13575#discussion_r953023755 but it's not related.
Patrick Cloke