Refactor how the `EventContext` class works, with the intention of reducing the amount of state we fetch from the DB during event processing.
The idea here is to get rid of the cached `current_state_ids` and `prev_state_ids` that live in the `EventContext`, and instead defer straight to the database (and its caching).
One change that may have a noticeable effect is that we now no longer prefill the `get_current_state_ids` cache on a state change. However, that query is relatively light, since its just a case of reading a table from the DB (unlike fetching state at an event which is more heavyweight). For deployments with workers this cache isn't even used.
Part of #12684
Refactor and convert `Linearizer` to async. This makes a `Linearizer`
cancellation bug easier to fix.
Also refactor to use an async context manager, which eliminates an
unlikely footgun where code that doesn't immediately use the context
manager could forget to release the lock.
Signed-off-by: Sean Quah <seanq@element.io>
When we get a partial_state response from send_join, store information in the
database about it:
* store a record about the room as a whole having partial state, and stash the
list of member servers too.
* flag the join event itself as having partial state
* also, for any new events whose prev-events are partial-stated, note that
they will *also* be partial-stated.
We don't yet make any attempt to interpret this data, so API calls (and a bunch
of other things) are just going to get incorrect data.
I've never found this terribly useful. I think it was added in the early days
of Synapse, without much thought as to what would actually be useful to log,
and has just been cargo-culted ever since.
Rather, it tends to clutter up debug logs with useless information.
This fixes a bug where we would accept an event whose `auth_events` include
rejected events, if the rejected event was shadowed by another `auth_event`
with same `(type, state_key)`.
The approach is to pass a list of auth events into
`check_auth_rules_for_event` instead of a dict, which of course means updating
the call sites.
This is an extension of #10956.
Broadly, the existing `event_auth.check` function has two parts:
* a validation section: checks that the event isn't too big, that it has the rught signatures, etc.
This bit is independent of the rest of the state in the room, and so need only be done once
for each event.
* an auth section: ensures that the event is allowed, given the rest of the state in the room.
This gets done multiple times, against various sets of room state, because it forms part of
the state res algorithm.
Currently, this is implemented with `do_sig_check` and `do_size_check` parameters, but I think
that makes everything hard to follow. Instead, we split the function in two and call each part
separately where it is needed.
Constructing an EventContext for an outlier is actually really simple, and
there's no sense in going via an `async` method in the `StateHandler`.
This also means that we can resolve a bunch of FIXMEs.
Part of #9744
Removes all redundant `# -*- coding: utf-8 -*-` lines from files, as python 3 automatically reads source code as utf-8 now.
`Signed-off-by: Jonathan de Jong <jonathan@automatia.nl>`
- Update black version to the latest
- Run black auto formatting over the codebase
- Run autoformatting according to [`docs/code_style.md
`](80d6dc9783/docs/code_style.md)
- Update `code_style.md` docs around installing black to use the correct version
This had two effects 1) it'd give the wrong answer and b) would iterate
*all* power levels in the auth chain of each event. The latter of which
can be *very* expensive for certain types of IRC bridge rooms that have
large numbers of power level changes.
We do state res with unpersisted events when calculating the new current state of the room, so that should be the only thing impacted. I don't think this is tooooo big of a deal as:
1. the next time a state event happens in the room the current state should correct itself;
2. in the common case all the unpersisted events' auth events will be pulled in by other state, so will still return the correct result (or one which is sufficiently close to not affect the result); and
3. we mostly use the state at an event to do important operations, which isn't affected by this.
I'd like to get a better insight into what we are doing with respect to state
res. The list of state groups we are resolving across should be short (if it
isn't, that's a massive problem in itself), so it should be fine to log it in
ite entiretly.
I've done some grepping and found approximately zero cases in which the
"shortcut" code delivered the result, so I've ripped that out too.
slots use less memory (and attribute access is faster) while slightly
limiting the flexibility of the class attributes. This focuses on objects
which are instantiated "often" and for short periods of time.
State res v2 across large data sets can be very CPU intensive, and if
all the relevant events are in the cache the algorithm will run from
start to finish within a single reactor tick. This can result in
blocking the reactor tick for several seconds, which can have major
repercussions on other requests.
To fix this we simply add the occaisonal `sleep(0)` during iterations to
yield execution until the next reactor tick. The aim is to only do this
for large data sets so that we don't impact otherwise quick resolutions.=
It was originally implemented by pulling the full auth chain of all
state sets out of the database and doing set comparison. However, that
can take a lot work if the state and auth chains are large.
Instead, lets try and fetch the auth chains at the same time and
calculate the difference on the fly, allowing us to bail early if all
the auth chains converge. Assuming that the auth chains do converge more
often than not, this should improve performance. Hopefully.
