Horton

Re: pgsql: Track last_inactive_time in pg_replication_slots.

Bertrand Drouvot <bertranddrouvot.pg@gmail.com>

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From: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: Robert Haas <robertmhaas@gmail.com>, shveta malik <shveta.malik@gmail.com>, Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>, Amit Kapila <akapila@postgresql.org>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2024-03-25T16:24:54Z
Lists: pgsql-hackers 
Hi,

On Mon, Mar 25, 2024 at 07:32:11PM +0530, Amit Kapila wrote:
> On Mon, Mar 25, 2024 at 6:57 PM Robert Haas <robertmhaas@gmail.com> wrote:
> > And I'm suspicious that having an exception for slots being synced is
> > a bad idea. That makes too much of a judgement about how the user will
> > use this field. It's usually better to just expose the data, and if
> > the user needs helps to make sense of that data, then give them that
> > help separately.
> 
> The reason we didn't set this for sync slots is that they won't be
> usable (one can't use them to decode WAL) unless standby is promoted
> [2]. But I see your point as well. So, I have copied the others
> involved in this discussion to see what they think.

Yeah I also see Robert's point. If we also sync the "last inactive time" field then
we would need to take care of the corner case mentioned by Shveta in [1] during
promotion.

[1]: https://www.postgresql.org/message-id/CAJpy0uCLu%2BmqAwAMum%3DpXE9YYsy0BE7hOSw_Wno5vjwpFY%3D63g%40mail.gmail.com

Regards,

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

Commits

  1. Allow synced slots to have their inactive_since.

  2. Change last_inactive_time to inactive_since in pg_replication_slots.

  3. Track last_inactive_time in pg_replication_slots.

  4. Remove vacuum_defer_cleanup_age