Re: speed up a logical replica setup

On Wed, Mar 27, 2024 at 1:47 AM Euler Taveira <euler@eulerto.com> wrote:
>
> On Tue, Mar 26, 2024, at 4:12 PM, Tomas Vondra wrote:
>
> Perhaps I'm missing something, but why is NUM_CONN_ATTEMPTS even needed?
> Why isn't recovery_timeout enough to decide if wait_for_end_recovery()
> waited long enough?
>
>
> It was an attempt to decoupled a connection failure (that keeps streaming the
> WAL) from recovery timeout. The NUM_CONN_ATTEMPTS guarantees that if the primary
> is gone during the standby recovery process, there is a way to bail out.
>

I think we don't need to check primary if the WAL corresponding to
consistent_lsn is already present on the standby. Shouldn't we first
check that? Once we ensure that the required WAL is copied, just
checking server_is_in_recovery() should be sufficient. I feel that
will be a direct way of ensuring what is required rather than
indirectly verifying the same (by checking pg_stat_wal_receiver) as we
are doing currently.

--
With Regards,
Amit Kapila.