Horton

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

Amit Kapila <amit.kapila16@gmail.com>

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From: Amit Kapila <amit.kapila16@gmail.com>
To: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Cc: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>, Nathan Bossart <nathandbossart@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2024-03-13T04:24:15Z
Lists: pgsql-hackers

Commits

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  1. Add a test for commit ac0e33136a using the injection point.

  2. Invalidate inactive replication slots.

  3. Fix incorrect slot type in BuildTupleHashTableExt

  4. Allow synced slots to have their inactive_since.

  5. Change last_inactive_time to inactive_since in pg_replication_slots.

  6. Track last_inactive_time in pg_replication_slots.

  7. Track invalidation_reason in pg_replication_slots.

  8. Add option force_initdb to PostgreSQL::Test::Cluster:init()

  9. Add a failover option to subscriptions.

  10. Allow setting failover property in the replication command.

  11. Allow to enable failover property for replication slots via SQL API.

  12. Track conflict_reason in pg_replication_slots.

  13. Log messages for replication slot acquisition and release.

  14. Remove vacuum_defer_cleanup_age

  15. Fix corruption due to vacuum_defer_cleanup_age underflowing 64bit xids

  16. meson: Add initial version of meson based build system

On Tue, Mar 12, 2024 at 10:10 PM Bharath Rupireddy
<bharath.rupireddyforpostgres@gmail.com> wrote:
>
> On Mon, Mar 11, 2024 at 3:44 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> >
> > Yes, your understanding is correct. I wanted us to consider having new
> > parameters like 'inactive_replication_slot_timeout' to be at
> > slot-level instead of GUC. I think this new parameter doesn't seem to
> > be the similar as 'max_slot_wal_keep_size' which leads to truncation
> > of WAL at global and then invalidates the appropriate slots. OTOH, the
> > 'inactive_replication_slot_timeout' doesn't appear to have a similar
> > global effect.
>
> last_inactive_at is tracked for each slot using which slots get
> invalidated based on inactive_replication_slot_timeout. It's like
> max_slot_wal_keep_size invalidating slots based on restart_lsn. In a
> way, both are similar, right?
>

There is some similarity but 'max_slot_wal_keep_size' leads to
truncation of WAL which in turn leads to invalidation of slots. Here,
I am also trying to be cautious in adding a GUC unless it is required
or having a slot-level parameter doesn't serve the need. Having said
that, I see that there is an argument that we should follow the path
of 'max_slot_wal_keep_size' GUC and there is some value to it but
still I think avoiding a new GUC for inactivity in the slot would
outweigh.

-- 
With Regards,
Amit Kapila.