Now that we wait for stream positions whenever we do a HTTP replication
hit, we need to be less brutal in the case where we do timeout (as we
have bugs around this).
We were incorrectly checking if the *local* token had been advanced, rather than the token for the remote instance.
In practice, I don't think this has caused any bugs due to where we use `wait_for_stream_position`, as critically we don't use it on instances that also write to the given streams (and so the local token will lag behind all remote tokens).
This creates a new store method, `process_replication_position` that
is called after `process_replication_rows`. By moving stream ID advances
here this guarantees any relevant cache invalidations will have been
applied before the stream is advanced.
This avoids race conditions where Python switches between threads mid
way through processing the `process_replication_rows` method where stream
IDs may be advanced before caches are invalidated due to class resolution
ordering.
See this comment/issue for further discussion:
https://github.com/matrix-org/synapse/issues/14158#issuecomment-1344048703
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.
* Add tests for StreamIdGenerator
* Drive-by: annotate all defs
* Revert "Revert "Remove slaved id tracker (#14376)" (#14463)"
This reverts commit d63814fd73, which in
turn reverted 36097e88c4. This restores
the latter.
* Fix StreamIdGenerator not handling unpersisted IDs
Spotted by @erikjohnston.
Closes#14456.
* Changelog
Co-authored-by: Nick Mills-Barrett <nick@fizzadar.com>
Co-authored-by: Erik Johnston <erik@matrix.org>
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.
This matches the multi instance writer ID generator class which can
both handle advancing the current token over replication and by calling
the database.
This adds support for the stable identifiers of MSC2285 while
continuing to support the unstable identifiers behind the configuration
flag. These will be removed in a future version.
More prep work for asyncronous caching, also makes all process_replication_rows methods consistent (presence handler already is so).
Signed off by Nick @ Beeper (@Fizzadar)
Bounce recalculation of current state to the correct event persister and
move recalculation of current state into the event persistence queue, to
avoid concurrent updates to a room's current state.
Also give recalculation of a room's current state a real stream
ordering.
Signed-off-by: Sean Quah <seanq@matrix.org>
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>
While `ReplicationEndpoint`s register themselves via `JsonResource`,
they pass a method that calls the handler, instead of the handler itself,
to `register_paths`. As a result, `JsonResource` will not correctly pick
up the `@cancellable` flag and we have to apply it ourselves.
Signed-off-by: Sean Quah <seanq@element.io>
