Horton

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

Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>

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From: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
To: Dilip Kumar <dilipbalaut@gmail.com>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2024-02-06T17:32:33Z
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 Tue, Feb 6, 2024 at 2:16 PM Dilip Kumar <dilipbalaut@gmail.com> wrote:
>
> > Thoughts?
> >
> +1 for the idea,  here are some comments on 0002, I will review other
> patches soon and respond.

Thanks for looking at it.

> +       <structfield>inactive_at</structfield> <type>timestamptz</type>
>
> Maybe we can change the field name to 'last_inactive_at'? or maybe the
> comment can explain timestampt at which slot was last inactivated.
> I think since we are already maintaining the inactive_count so better
> to explicitly say this is the last invaliding time.

last_inactive_at looks better, so will use that in the next version of
the patch.

> 2.
> + /*
> + * XXX: Can inactive_count of type uint64 ever overflow? It takes
> + * about a half-billion years for inactive_count to overflow even
> + * if slot becomes inactive for every 1 millisecond. So, using
> + * pg_add_u64_overflow might be an overkill.
> + */
>
> Correct we don't need to use pg_add_u64_overflow for this counter.

Will remove this comment in the next version of the patch.

> + /* Convert to numeric. */
> + snprintf(buf, sizeof buf, UINT64_FORMAT, slot_contents.data.inactive_count);
> + values[i++] = DirectFunctionCall3(numeric_in,
> +   CStringGetDatum(buf),
> +   ObjectIdGetDatum(0),
> +   Int32GetDatum(-1));
>
> What is the purpose of doing this? I mean inactive_count is 8 byte
> integer and you can define function outparameter as 'int8' which is 8
> byte integer.  Then you don't need to convert int to string and then
> to numeric?

Nope, it's of type uint64, so reporting it as numeric is a way
typically used elsewhere - see code around /* Convert to numeric. */.

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