Re: Synchronizing slots from primary to standby

Hi,

On Thu, Feb 01, 2024 at 04:12:43PM +0530, Amit Kapila wrote:
> On Thu, Jan 25, 2024 at 11:26 AM Bertrand Drouvot
> <bertranddrouvot(dot)pg(at)gmail(dot)com> wrote:
> >
> > On Wed, Jan 24, 2024 at 04:09:15PM +0530, shveta malik wrote:
> > > On Wed, Jan 24, 2024 at 2:38 PM Bertrand Drouvot
> > > <bertranddrouvot(dot)pg(at)gmail(dot)com> wrote:
> > > >
> > > > I also see Sawada-San's point and I'd vote for "sync_replication_slots". Then for
> > > > the current feature I think "failover" and "on" should be the values to turn the
> > > > feature on (assuming "on" would mean "all kind of supported slots").
> > >
> > > Even if others agree and we change this GUC name to
> > > "sync_replication_slots", I feel we should keep the values as "on" and
> > > "off" currently, where "on" would mean 'sync failover slots' (docs can
> > > state that clearly).
> >
> > I gave more thoughts on it and I think the values should only be "failover" or
> > "off".
> >
> > The reason is that if we allow "on" and change the "on" behavior in future
> > versions (to support more than failover slots) then that would change the behavior
> > for the ones that used "on".
> >
>
> I again thought on this point and feel that even if we start to sync
> say physical slots their purpose would also be to allow
> failover/switchover, otherwise, there is no use of syncing the slots.

Yeah, I think this is a good point.

> So, by that theory, we can just go for naming it as
> sync_failover_slots or simply sync_slots with values 'off' and 'on'.
> Now, if these are used for switchover then there is an argument that
> adding 'failover' in the GUC name could be confusing but I feel
> 'failover' is used widely enough that it shouldn't be a problem for
> users to understand, otherwise, we can go with simple name like
> sync_slots as well.
>

I agree and "on"/"off" looks enough to me now. As far the GUC name I've the
feeling that "replication" should be part of it, and think that sync_replication_slots
is fine. The reason behind is that "sync_slots" could be confusing if in the
future other kind of "slot" (other than replication ones) are added in the engine.

Thoughts?

Regards,

--
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
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