Re: Improve pg_sync_replication_slots() to wait for primary to advance

On Wed, Dec 10, 2025 at 8:10 AM Ajin Cherian <itsajin(at)gmail(dot)com> wrote:
>
> On Wed, Dec 10, 2025 at 1:29 PM Chao Li <li(dot)evan(dot)chao(at)gmail(dot)com> wrote:
> >
> > Hi Ajin,
> >
> > I’d like to revisit this patch, but looks like 04396eacd3faeaa4fa3d084a6749e4e384bdf0db has some conflicts to this patch. So can you please rebase this patch?
> >
> > Best regards,
> > --
>
> It's been rebased. Have a look at the latest version.
>

Few comments on 001:

1)
/*
* Emit an error if a promotion or a concurrent sync call is in progress.
* Otherwise, advertise that a sync is in progress.
*/
static void
check_and_set_sync_info

We need to change this comment because now this function does not
handle promotion case.

2)
+  if (sync_process_pid!= InvalidPid)
+    kill(sync_process_pid, SIGUSR1);

We need to have space between sync_process_pid and '!='

3)
+ * Exit or throw errors if relevant GUCs have changed depending on whether

errors->error

4)
In slotsync_reread_config(), even when we mark parameter_changed=true
in the first if-block, we still go to the second if-block which was
not needed. So shall we make second if-block as else-if to avoid
this? Thoughts?

5)
As discussed in [1], we can make this change in ProcessSlotSyncInterrupts():

'replication slot synchronization worker is shutting down because
promotion is triggered'
to
'replication slot synchronization worker will stop because promotion
is triggered'

[1]: https://www.postgresql.org/message-id/6AE56C64-F760-4CBD-BABF-72633D3F7B5E%40gmail.com

thanks
Shveta