Ensure we only load an event from the DB once when the same event is requested multiple times at once.

Co-authored-by: Erik Johnston <erik@matrix.org>

Setting the value will help PostgreSQL free up memory by recycling
the connections in the connection pool.

Signed-off-by: Toni Spets <toni.spets@iki.fi>

This PR is tantamount to running:

    python3.8 -m com2ann -v 6 tests/

(com2ann requires python 3.8 to run)

This adds a simple best effort locking mechanism that works cross workers.

Work on https://github.com/matrix-org/matrix-doc/pull/2716

Reformat all files with the new version.

Signed-off-by: Marcus Hoffmann <bubu@bubu1.eu>

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.

The hope here is that by moving all the schema files into synapse/storage/schema, it gets a bit easier for newcomers to navigate.

It certainly got easier for me to write a helpful README. There's more to do on that front, but I'll follow up with other PRs for that.

I went through and removed a bunch of cruft that was lying around for compatibility with old Python versions. This PR also will now prevent Synapse from starting unless you're running Python 3.6+.

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&gt;`>

Related: #8334
Deprecated in: #9429 - Synapse 1.28.0 (2021-02-25)

`GET /_synapse/admin/v1/users/<user_id>` has no
- unit tests
- documentation

API in v2 is available (#5925 - 12/2019, v1.7.0).
API is misleading. It expects `user_id` and returns a list of all users.

Signed-off-by: Dirk Klimpel <dirk@klimpel.org>

Part of #9366

Adds in fixes for B006 and B008, both relating to mutable parameter lint errors.

Signed-off-by: Jonathan de Jong <jonathan@automatia.nl>

This uses a simplified version of get_chain_cover_difference to calculate
auth chain of events.

Unfortunately this doesn't test re-joining the room since
that requires having another homeserver to query over
federation, which isn't easily doable in unit tests.

 - Update black version to the latest
 - Run black auto formatting over the codebase
    - Run autoformatting according to [`docs/code_style.md
`](https://github.com/matrix-org/synapse/blob/80d6dc9783aa80886a133756028984dbf8920168/docs/code_style.md)
 - Update `code_style.md` docs around installing black to use the correct version

We do this by allowing a single iteration to process multiple rooms at a
time, as there are often a lot of really tiny rooms, which can massively
slow things down.

This only applies if the user's data is to be erased.

This allows for efficiently finding which users ignore a particular
user.

Co-authored-by: Erik Johnston <erik@matrix.org>

If we see stale extremities while persisting events, and notice that
they don't change the result of state resolution, we drop them.

* Use the simple dictionary in fts for the user directory

* Clarify naming

This is so that we can choose which algorithm to use based on the room ID.