Thank you Michael. I agree with you. Relevant part can be removed from the document and eliminate the confusion at least.
Michael Paquier <michael@paquier.xyz>, 5 Oca 2021 Sal, 10:17 tarihinde şunu yazdı:
On Mon, Jan 04, 2021 at 04:12:34PM +0300, Amine Tengilimoglu wrote: > When I read the pg_rewind PG12 doc. It says: > > "... but if the target cluster ran for a long time after the divergence, > the old WAL files might no longer be present. In that case, they can be > manually copied from the WAL archive to the pg_wal directory,* or fetched > on startup by configuring **primary_conninfo > <https://www.postgresql.org/docs/12/runtime-config-replication.html#GUC-PRIMARY-CONNINFO> > or restore_command > <https://www.postgresql.org/docs/12/runtime-config-wal.html#GUC-RESTORE-COMMAND>* > .". > > So I thought we could use restore_command. But when I try to use it , I > see it doesn't work either.
I agree with your point that the docs of 9.6~12 are confusing here. It makes no sense to mention restore_command or primary_conninfo to fetch WAL segments for the target to allow pg_rewind to find the point of divergence because the target is already offline when we look at that. Mentioning restore_command/primary_conninfo for recovery purposes could make sense in the context in the follow-up paragraph though, where the target gets restarted, after the rewind. But the uses are different.
The docs of 13~ got that right when -c has been introduced by rewording this sentence as "or run pg_rewind with the -c option to automatically retrieve them from the WAL archive". So let's get rid of ", or fetched on startup by configuring primary_conninfo or restore_command." ("or fetched on startup by configuring recovery.conf" in some older branches). This confusion has been introduced by 878bd9a, down to 9.6.
