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: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2024-02-21T14:40:00Z
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 →
  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 Wed, Feb 21, 2024 at 5:55 PM Bertrand Drouvot
<bertranddrouvot.pg@gmail.com> wrote:
>
> > As far as the 0001 patch is concerned, it reports the
> > invalidation_reason as long as slot_contents.data.invalidated !=
> > RS_INVAL_NONE. I think this is okay.
> >
> > Thoughts?
>
> Yeah, looking at the code I agree that looks ok. OTOH, that looks confusing,
> maybe we should add a few words about it in the doc?

I'll think about it.

> Looking at v5-0001:
>
> +      <entry role="catalog_table_entry"><para role="column_definition">
> +       <structfield>invalidation_reason</structfield> <type>text</type>
> +      </para>
> +      <para>
>
> My initial thought was to put "conflict" value in this new field in case of
> conflict (not to mention the conflict reason in it). With the current proposal
> invalidation_reason could report the same as conflict_reason, which sounds weird
> to me.
>
> Does that make sense to you to use "conflict" as value in "invalidation_reason"
> when the slot has "conflict_reason" not NULL?

I'm thinking the other way around - how about we revert
https://git.postgresql.org/gitweb/?p=postgresql.git;a=commitdiff;h=007693f2a3ac2ac19affcb03ad43cdb36ccff5b5,
that is, put in place "conflict" as a boolean and introduce
invalidation_reason the text form. So, for logical slots, whenever the
"conflict" column is true, the reason is found in invaldiation_reason
column? How does it sound? Again the debate might be "conflict" vs
"invalidation", but that looks clean IMHO.

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