Dear Vitaly,
I've been working on the bug...
> This assert was introduced in the patch. Now, I think, it is a wrong one. Let me
> please explain one of the possible scenarios when it can be triggered. In case
> of physical replication, when walsender receives a standby reply message, it
> calls PhysicalConfirmReceivedLocation function which updates slots' restart_lsn
> from received flush_lsn value. This value may be older than the saved value.
To confirm, can you tell me the theory why the walsender received old LSN?
It is sent by the walreceiver, so is there a case that LogstreamResult.Flush can go backward?
Not sure we can accept the situation.
Best regards,
Hayato Kuroda
FUJITSU LIMITED