Re: pg_copy_logical_replication_slot doesn't copy the failover property

On Sat, Feb 22, 2025 at 11:26 AM Shlok Kyal <shlok(dot)kyal(dot)oss(at)gmail(dot)com> wrote:
>
> Adding Amit to the thread.
>

Thanks.

Looking at the original complaint:

> It says
> * To avoid potential issues with the slot synchronization where the
> * restart_lsn of a replication slot can go backward, we set the
> * failover option to false here. This situation occurs when a slot
> * on the primary server is dropped and immediately replaced with a
> * new slot of the same name, created by copying from another existing
> * slot. However, the slot synchronization will only observe the
> * restart_lsn of the same slot going backward.

It would be better to update the comments as well to make the
potential issues with slot synchronization clear or mention the
reference of other place where we have comments related to this race
condition. Also, I think it is better to write about two_phase in the
comments as well as in docs unless already mentioned. If you agree
with updating the comments as well, shall we redirect this to hackers?

> >
> > IIUC the two_phase field is also not copied from the source slot. I
> > think we can clarify in the doc that these two fields are not copied.
> >

+1.

--
With Regards,
Amit Kapila.