Re: Introduce XID age and inactive timeout based replication slot invalidation

Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>

From: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>

To: shveta malik <shveta.malik@gmail.com>

Cc: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>, Masahiko Sawada <sawada.mshk@gmail.com>, Amit Kapila <amit.kapila16@gmail.com>, Nathan Bossart <nathandbossart@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>

Date: 2024-04-03T05:47:41Z

Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

Add a test for commit ac0e33136a using the injection point.
- 8a695d7998be 18.0 landed
Invalidate inactive replication slots.
- ac0e33136abc 18.0 landed
Fix incorrect slot type in BuildTupleHashTableExt
- d96d1d5152f3 18.0 cited
Allow synced slots to have their inactive_since.
- 6f132ed693b6 17.0 landed
Change last_inactive_time to inactive_since in pg_replication_slots.
- 6d49c8d4b4f4 17.0 landed
Track last_inactive_time in pg_replication_slots.
- a11f330b5584 17.0 landed
Track invalidation_reason in pg_replication_slots.
- 6ae701b4378d 17.0 landed
Add option force_initdb to PostgreSQL::Test::Cluster:init()
- ff9e1e764fcc 17.0 cited
Add a failover option to subscriptions.
- 776621a5e479 17.0 cited
Allow setting failover property in the replication command.
- 73292404370c 17.0 cited
Allow to enable failover property for replication slots via SQL API.
- c393308b69d2 17.0 cited
Track conflict_reason in pg_replication_slots.
- 007693f2a3ac 17.0 cited
Log messages for replication slot acquisition and release.
- 7c3fb505b14e 17.0 cited
Remove vacuum_defer_cleanup_age
- 1118cd37eb61 16.0 cited
Fix corruption due to vacuum_defer_cleanup_age underflowing 64bit xids
- be504a3e974d 16.0 cited
meson: Add initial version of meson based build system
- e6927270cd18 16.0 cited

Attachments

v31-0001-Allow-synced-slots-to-have-their-own-inactive_si.patch (application/x-patch) patch v31-0001
v31-0002-Add-inactive_timeout-based-replication-slot-inva.patch (application/x-patch) patch v31-0002

On Wed, Apr 3, 2024 at 8:38 AM shveta malik <shveta.malik@gmail.com> wrote:
>
> > > Or a simple solution is that the slotsync worker updates
> > > inactive_since as it does for non-synced slots, and disables
> > > timeout-based slot invalidation for synced slots.
>
> I like this idea better, it takes care of such a case too when the
> user is relying on sync-function rather than worker and does not want
> to get the slots invalidated in between 2 sync function calls.

Please find the attached v31 patches implementing the above idea:

- synced slots get their on inactive_since just like any other slot
- synced slots don't get invalidated due to inactive timeout because
such slots not considered active at all as they don't perform logical
decoding (of course, they will perform in fast_forward mode to fix the
other data loss issue, but they don't generate changes for them to be
called as *active* slots)
- synced slots inactive_since is set to current timestamp after the
standby gets promoted to help inactive_since interpret correctly just
like any other slot.

--
Bharath Rupireddy
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com