Whenever we want to persist an event, we first compute an event context,
which includes the state at the event and a flag indicating whether the
state is partial. After a lot of processing, we finally try to store the
event in the database, which can fail for partial state events when the
containing room has been un-partial stated in the meantime.
We detect the race as a foreign key constraint failure in the data store
layer and turn it into a special `PartialStateConflictError` exception,
which makes its way up to the method in which we computed the event
context.
To make things difficult, the exception needs to cross a replication
request: `/fed_send_events` for events coming over federation and
`/send_event` for events from clients. We transport the
`PartialStateConflictError` as a `409 Conflict` over replication and
turn `409`s back into `PartialStateConflictError`s on the worker making
the request.
All client events go through
`EventCreationHandler.handle_new_client_event`, which is called in
*a lot* of places. Instead of trying to update all the code which
creates client events, we turn the `PartialStateConflictError` into a
`429 Too Many Requests` in
`EventCreationHandler.handle_new_client_event` and hope that clients
take it as a hint to retry their request.
On the federation event side, there are 7 places which compute event
contexts. 4 of them use outlier event contexts:
`FederationEventHandler._auth_and_persist_outliers_inner`,
`FederationHandler.do_knock`, `FederationHandler.on_invite_request` and
`FederationHandler.do_remotely_reject_invite`. These events won't have
the partial state flag, so we do not need to do anything for then.
The remaining 3 paths which create events are
`FederationEventHandler.process_remote_join`,
`FederationEventHandler.on_send_membership_event` and
`FederationEventHandler._process_received_pdu`.
We can't experience the race in `process_remote_join`, unless we're
handling an additional join into a partial state room, which currently
blocks, so we make no attempt to handle it correctly.
`on_send_membership_event` is only called by
`FederationServer._on_send_membership_event`, so we catch the
`PartialStateConflictError` there and retry just once.
`_process_received_pdu` is called by `on_receive_pdu` for incoming
events and `_process_pulled_event` for backfill. The latter should never
try to persist partial state events, so we ignore it. We catch the
`PartialStateConflictError` in `on_receive_pdu` and retry just once.
Refering to the graph of code paths in
https://github.com/matrix-org/synapse/issues/12988#issuecomment-1156857648
may make the above make more sense.
Signed-off-by: Sean Quah <seanq@matrix.org>
* Cast to postgres types when handling postgres db
* Remove unused method
* Easy annotations
* Annotate create_room
* Use `ParamSpec` to annotate looping_call
* Annotate `default_config`
* Track `now` as a float
`time_ms` returns an int like the proper Synapse `Clock`
* Introduce a `Timer` dataclass
* Introduce a Looper type
* Suppress checking of a mock
* tests.utils is typed
* Changelog
* Whoops, import ParamSpec from typing_extensions
* ditch the psycopg2 casts
==============================
Bugfixes
--------
- Fix unread counts for users on large servers. Introduced in v1.62.0rc1. ([\#13140](https://github.com/matrix-org/synapse/issues/13140))
- Fix DB performance when deleting old push notifications. Introduced in v1.62.0rc1. ([\#13141](https://github.com/matrix-org/synapse/issues/13141))
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Merge tag 'v1.62.0rc2' into develop
Synapse 1.62.0rc2 (2022-07-01)
==============================
Bugfixes
--------
- Fix unread counts for users on large servers. Introduced in v1.62.0rc1. ([\#13140](https://github.com/matrix-org/synapse/issues/13140))
- Fix DB performance when deleting old push notifications. Introduced in v1.62.0rc1. ([\#13141](https://github.com/matrix-org/synapse/issues/13141))
When we receive an event over federation during a faster join, there is no need
to wait for full state, since we have a whole reconciliation process designed
to take the partial state into account.
* Extend the auth rule checks for `m.room.create` events
... and move them up to the top of the function. Since the no auth_events are
allowed for m.room.create events, we may as well get the m.room.create event
checks out of the way first.
* Add a test for create events with prev_events
