To perform an emulated upsert into a table safely, we must either:
* lock the table,
* be the only writer upserting into the table
* or rely on another unique index being present.
When the 2nd or 3rd cases were applicable, we previously avoided locking
the table as an optimization. However, as seen in #14406, it is easy to
slip up when adding new schema deltas and corrupt the database.
The only time we lock when performing emulated upserts is while waiting
for background updates on postgres. On sqlite, we do no locking at all.
Let's remove the option to skip locking tables, so that we don't shoot
ourselves in the foot again.
Signed-off-by: Sean Quah <seanq@matrix.org>
* 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>
This matches the multi instance writer ID generator class which can
both handle advancing the current token over replication and by calling
the database.
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)
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>`
Introduced in #9104
This wasn't picked up by the tests as this is all fine the first time you run Synapse (after upgrading), but then when you restart the wrong value is pulled from `stream_positions`.
