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

Amit Kapila <amit.kapila16@gmail.com>

From: Amit Kapila <amit.kapila16@gmail.com>

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

Cc: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>, Peter Smith <smithpb2250@gmail.com>, Ajin Cherian <itsajin@gmail.com>, Bertrand Drouvot <bertranddrouvot.pg@gmail.com>, Masahiko Sawada <sawada.mshk@gmail.com>, Nathan Bossart <nathandbossart@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>

Date: 2024-09-05T03:55:51Z

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

On Wed, Sep 4, 2024 at 2:49 PM shveta malik <shveta.malik@gmail.com> wrote:
>
> On Wed, Sep 4, 2024 at 9:17 AM shveta malik <shveta.malik@gmail.com> wrote:
> >
> > On Tue, Sep 3, 2024 at 3:01 PM shveta malik <shveta.malik@gmail.com> wrote:
> > >
> > >
>
>
> 1)
> It is related to one of my previous comments (pt 3 in [1]) where I
> stated that inactive_since should not keep on changing once a slot is
> invalidated.
>

Agreed. Updating the inactive_since for a slot that is already invalid
is misleading.

>
>
> 2)
> One more issue in this message is, once I set
> replication_slot_inactive_timeout to a bigger value, it becomes more
> misleading. This is because invalidation was done in the past using
> previous value while message starts showing new value:
>
> ALTER SYSTEM SET replication_slot_inactive_timeout TO '36h';
>
> --see 129600 secs in DETAIL and the current time.
> postgres=# SELECT * FROM pg_replication_slot_advance('mysubnew1_1',
> pg_current_wal_lsn());
> ERROR:  can no longer get changes from replication slot "mysubnew1_1"
> DETAIL:  The slot became invalid because it was inactive since
> 2024-09-04 10:06:38.980939+05:30, which is more than 129600 seconds
> ago.
> postgres=# select now();
>                now
> ----------------------------------
>  2024-09-04 10:07:35.201894+05:30
>
> I feel we should change this message itself.
>

+1.

-- 
With Regards,
Amit Kapila.