If backfilling is slow then the client may time out and retry, causing
Synapse to start a new `/backfill` before the existing backfill has
finished, duplicating work.
This adds quite a lot of OpenTracing decoration for database activity. Specifically it adds tracing at four different levels:
* emit a span for each "interaction" - ie, the top level database function that we tend to call "transaction", but isn't really, because it can end up as multiple transactions.
* emit a span while we hold a database connection open
* emit a span for each database transaction - actual actual transaction.
* emit a span for each database query.
I'm aware this might be quite a lot of overhead, but even just running it on a local Synapse it looks really interesting, and I hope the overhead can be offset just by turning down the sampling frequency and finding other ways of tracing requests of interest (eg, the `force_tracing_for_users` setting).
The existing tracing reports an error each time there is a timeout, which isn't
really representative.
Additionally, we log things about the way `wait_for_events` works
(eg, the result of the callback) to the *parent* span, which is confusing.
Empirically, this helped my server considerably when handling gaps in Matrix HQ. The problem was that we would repeatedly call have_seen_events for the same set of (50K or so) auth_events, each of which would take many minutes to complete, even though it's only an index scan.
==============================
Bugfixes
--------
- Fix a bug introduced in v1.35.0rc1 when calling the spaces summary API via a GET request. ([\#10079](https://github.com/matrix-org/synapse/issues/10079))
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Merge tag 'v1.35.0rc2' into develop
Synapse 1.35.0rc2 (2021-05-27)
==============================
Bugfixes
--------
- Fix a bug introduced in v1.35.0rc1 when calling the spaces summary API via a GET request. ([\#10079](https://github.com/matrix-org/synapse/issues/10079))
* Make `invalidate` and `invalidate_many` do the same thing
... so that we can do either over the invalidation replication stream, and also
because they always confused me a bit.
* Kill off `invalidate_many`
* changelog
`keylen` seems to be a thing that is frequently incorrectly set, and we don't really need it.
The only time it was used was to figure out if we had removed a subtree in `del_multi`, which we can do better by changing `TreeCache.pop` to return a different type (`TreeCacheNode`).
Commits should be independently reviewable.
* Fix /upload 500'ing when presented a very large image
Catch DecompressionBombError and re-raise as ThumbnailErrors
* Set PIL's MAX_IMAGE_PIXELS to match homeserver.yaml
to get it to bomb out quicker, to load less into memory
in the case of super large images
* Add changelog entry for 10029
Fixes: https://github.com/matrix-org/synapse/issues/9962
This is a fix for above problem.
I fixed it by swaping the order of insertion of new records and deletion of old ones. This ensures that we don't delete fresh database records as we do deletes before inserts.
Signed-off-by: Marek Matys <themarcq@gmail.com>
Also add support for giving a callback to generate the JSON object to
verify. This should reduce memory usage, as we no longer have the event
in memory in dict form (which has a large memory footprint) for extend
periods of time.
Instead of parsing the full response to `/send_join` into Python objects (which can be huge for large rooms) and *then* parsing that into events, we instead use ijson to stream parse the response directly into `EventBase` objects.
