On startup `MultiWriteIdGenerator` fetches the maximum stream ID for
each instance from the table and uses that as its initial "current
position" for each writer. This is problematic as a) it involves either
a scan of events table or an index (neither of which is ideal), and b)
if rows are being persisted out of order elsewhere while the process
restarts then using the maximum stream ID is not correct. This could
theoretically lead to race conditions where e.g. events that are
persisted out of order are not sent down sync streams.
We fix this by creating a new table that tracks the current positions of
each writer to the stream, and update it each time we finish persisting
a new entry. This is a relatively small overhead when persisting events.
However for the cache invalidation stream this is a much bigger relative
overhead, so instead we note that for invalidation we don't actually
care about reliability over restarts (as there's no caches to
invalidate) and simply don't bother reading and writing to the new table
in that particular case.
... and to show that it does something slightly different to
`_get_e2e_device_keys_txn`.
`include_all_devices` and `include_deleted_devices` were never used (and
`include_deleted_devices` was broken, since that would cause `None`s in the
result which were not handled in the loop below.
Add some typing too.
* Don't raise session_id errors on submit_token if request_token_inhibit_3pid_errors is set
* Changelog
* Also wait some time before responding to /requestToken
* Incorporate review
* Update synapse/storage/databases/main/registration.py
Co-authored-by: Andrew Morgan <1342360+anoadragon453@users.noreply.github.com>
* Incorporate review
Co-authored-by: Andrew Morgan <1342360+anoadragon453@users.noreply.github.com>
The function is used for two purposes: 1) for subscribers of streams to
get a token they can use to get further updates with, and 2) for
replication to track position of the writers of the stream.
For streams with a single writer the two scenarios produce the same
result, however the situation becomes complicated for streams with
multiple writers. The current `MultiWriterIdGenerator` does not
correctly handle the first case (which is not an issue as its only used
for the `caches` stream which nothing subscribes to outside of
replication).
Calls `self.get_success` on all deferred methods instead of abusing `self.pump()`. This has the benefit of working with coroutines, as well as checking that method execution completed successfully.
There are also a few small cleanups that I made in the process.
The idea here is that if an instance persists an event via the replication HTTP API it can return before we receive that event over replication, which can lead to races where code assumes that persisting an event immediately updates various caches (e.g. current state of the room).
Most of Synapse doesn't hit such races, so we don't do the waiting automagically, instead we do so where necessary to avoid unnecessary delays. We may decide to change our minds here if it turns out there are a lot of subtle races going on.
People probably want to look at this commit by commit.
==============================
Bugfixes
--------
- Fix a long-standing bug which could cause messages not to be sent over federation, when state events with state keys matching user IDs (such as custom user statuses) were received. ([\#7376](https://github.com/matrix-org/synapse/issues/7376))
- Restore compatibility with non-compliant clients during the user interactive authentication process, fixing a problem introduced in v1.13.0rc1. ([\#7483](https://github.com/matrix-org/synapse/issues/7483))
Internal Changes
----------------
- Fix linting errors in new version of Flake8. ([\#7470](https://github.com/matrix-org/synapse/issues/7470))
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Merge tag 'v1.13.0rc2' into develop
Synapse 1.13.0rc2 (2020-05-14)
==============================
Bugfixes
--------
- Fix a long-standing bug which could cause messages not to be sent over federation, when state events with state keys matching user IDs (such as custom user statuses) were received. ([\#7376](https://github.com/matrix-org/synapse/issues/7376))
- Restore compatibility with non-compliant clients during the user interactive authentication process, fixing a problem introduced in v1.13.0rc1. ([\#7483](https://github.com/matrix-org/synapse/issues/7483))
Internal Changes
----------------
- Fix linting errors in new version of Flake8. ([\#7470](https://github.com/matrix-org/synapse/issues/7470))
Fix a bug where the `get_joined_users` cache could be corrupted by custom
status events (or other state events with a state_key matching the user ID).
The bug was introduced by #2229, but has largely gone unnoticed since then.
Fixes#7099, #7373.
The aim here is to get to a stage where we have a `PersistEventStore` that holds all the write methods used during event persistence, so that we can take that class out of the `DataStore` mixin and instansiate it separately. This will allow us to instansiate it on processes other than master, while also ensuring it is only available on processes that are configured to write to events stream.
This is a bit of an architectural change, where we end up with multiple classes per data store (rather than one per data store we have now). We end up having:
1. Storage classes that provide high level APIs that can talk to multiple data stores.
2. Data store modules that consist of classes that must point at the same database instance.
3. Classes in a data store that can be instantiated on processes depending on config.
