On Thu, May 29, 2025 at 5:02 PM Michael Paquier <michael@paquier.xyz> wrote:
nd master versions.
Yeah, I think that this is a sensible move. Documenting the reason why GetXLogReplayRecPtr() is called is important, but the comment you are suggesting could be better, IMO, say: "For cascading logical WAL senders, we use the replay LSN rather than the flush LSN, as decoding would only happen with records already replayed. This distinction is important especially during the shutdown sequence, as cascading logical WAL senders can only catch up with records that have been already replayed, not flushed."
That feels that I'm repeating myself a bit twice if formulated this way. If you have a better suggestion, feel free..
I think this new fix is much better and cleaner. A suggestion for the comment: "For cascading logical WAL senders, we use the replay LSN instead of the flush LSN, since logical decoding on a standby only processes WAL that has been replayed. This distinction becomes particularly important during shutdown, as new WAL is no longer replayed and the last replayed LSN marks the furthest point up to which decoding can proceed."
