Re: pgsql: Track last_inactive_time in pg_replication_slots.

On Tue, Mar 26, 2024 at 9:38 AM shveta malik <shveta.malik@gmail.com> wrote:
>
> On Mon, Mar 25, 2024 at 9:54 PM Bertrand Drouvot
> <bertranddrouvot.pg@gmail.com> wrote:
> >
> > 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.
>
> I have suggested one potential solution for that in [1]. Please have a look.
>
> [1]:
https://www.postgresql.org/message-id/CAJpy0uB-yE%2BRiw7JQ4hW0%2BigJxvPc%2Brq%2B9c7WyTa1Jz7%2B2gAiA%40mail.gmail.com

I posted the v21 patch implementing the above idea in the other thread
- https://www.postgresql.org/message-id/CALj2ACXRFx9g7A9RFJZF7eBe%3Dzxk7%3DapMRFuCgJJKYB7O%3Dvgwg%40mail.gmail.com.
For ease, I'm also attaching the patch in here.

--
Bharath Rupireddy
PostgreSQL Contributors Team
RDS Open Source Databases
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