Hi, On Fri, Jun 18, 2021 at 5:42 PM Andrey Borodin <x4...@yandex-team.ru> wrote: > > If we run 'pg_rewind --restore-target-wal' there must be restore_command in > config of target installation. But if the config is not within > $PGDATA\postgresql.conf pg_rewind cannot use it. > If we run postmaster with `-c > config_file=/etc/postgresql/10/data/postgresql.conf`, we simply cannot use > the feature. We solved the problem by putting config into PGDATA only during > pg_rewind, but this does not seem like a very robust solution. >
Yeah, Michael was against it, while we had no good arguments, so Alexander removed it, IIRC. This example sounds reasonable to me. I also recall some complaints from PostgresPro support folks, that it is sad to not have a cli option to pass restore_command. However, I just thought about another recent feature --- ensure clean shutdown, which is turned on by default. So you usually run Postgres with one config, but pg_rewind may start it with another, although in single-user mode. Is it fine for you? > > Maybe we could add "-C, --target-restore-command=COMMAND target WAL > restore_command\n" as was proposed within earlier versions of the patch[0]? > Or instruct pg_rewind to pass config to 'postgres -C restore_command' run? Hm, adding --target-restore-command is the simplest way, sure, but forwarding something like '-c config_file=...' to postgres sounds interesting too. Could it have any use case beside providing a restore_command? I cannot imagine anything right now, but if any exist, then it could be a more universal approach. > > From my POV adding --target-restore-command is simplest way, I can extract > corresponding portions from original patch. > I will have a look, maybe I even already have this patch separately. I remember that we were considering adding this option to PostgresPro, when we did a backport of this feature. -- Alexey Kondratov
