RE: Doc: fix the note related to the GUC "synchronized_standby_slots"

On Monday, August 26, 2024 5:37 PM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
>
> On Mon, Aug 26, 2024 at 1:30 PM <Masahiro(dot)Ikeda(at)nttdata(dot)com> wrote:
> >
> > When I read the following documentation related to the
> "synchronized_standby_slots", I misunderstood that data loss would not occur
> in the case of synchronous physical replication. However, this is incorrect (see
> reproduce.txt).
> >
> > > Note that in the case of asynchronous replication, there remains a risk of
> data loss for transactions committed on the former primary server but have yet
> to be replicated to the new primary server.
> > https://www.postgresql.org/docs/17/logical-replication-failover.html
> >
> > Am I missing something?
> >
>
> It seems part of the paragraph: "Note that in the case of asynchronous
> replication, there remains a risk of data loss for transactions committed on the
> former primary server but have yet to be replicated to the new primary server." is
> a bit confusing. Will it make things clear to me if we remove that part?

I think the intention is to address a complaint[1] that the date inserted on
primary after the primary disconnects with the standby is still lost after
failover. But after rethinking, maybe it's doesn't directly belong to the topic in
the logical failover section because it's a general fact for async replication.
If we think it matters, maybe we can remove this part and slightly modify
another part:

parameter ensures a seamless transition of those subscriptions after the
standby is promoted. They can continue subscribing to publications on the
- new primary server without losing data.
+ new primary server without losing that has already been replicated and
+ flushed on the standby server.

[1] https://www.postgresql.org/message-id/ZfRe2%2BOxMS0kvNvx%40ip-10-97-1-34.eu-west-3.compute.internal

Best Regards,
Hou zj