Re: In case of network issues, how long before archive_command does retries

Hello Laurenz,

Thanks for the reply. That would mean the source code is here:
https://github.com/postgres/postgres/blob/REL_11_0/src/backend/postmaster/pgarch.c

Just to be sure, the "signal" you speak of, this is the result of the
command executed by archive_command?

If my understanding of the code is right, if no SIGTERM or other signal
arrives, it won't ever happen that a walarchive is skipped if the
archive_command fails too many times or takes too long? It will simply
check again every 60 seconds(PGARCH_AUTOWAKE_INTERVAL) ? Or is the 60
seconds the point where it stops trying, waiting for the next time
archive_command is invoked?

I'm assuming that as long as the file is still in the pg_wal directory and
as long as there is no ".done" file for that walarchive under
pg_wal/archive_status, it will keep trying forever(or until someone
forcefully switches the timeline with for instance a basebackup)?

Apologies, I already sent this message once, but only to Laurenz. Sending
again to have it in the archives.

Regards,
Koen

On Thu, May 19, 2022 at 9:10 AM Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at>
wrote:

> On Wed, 2022-05-18 at 22:51 +0200, Koen De Groote wrote:
> > I've got a setup where archive_command will gzip the wal archive to a
> directory that is itself an NFS mount.
> >
> > When connection is gone or blocked, archive_command fails after the
> timeout specified by the NFS mount, as expected. (for a soft mount. hard
> mount hangs, as expected)
> >
> > However, on restoring connection, it's not clear to me how long it takes
> before the command is retried.
> >
> > Experience says "a few minutes", but I can't find documentation on an
> exact algorithm.
> >
> > To be clear, the question is: if archive_command fails, what are the
> specifics of retrying? Is there a timeout? How is that timeout defined?
> >
> > Is this detailed somewhere? Perhaps in the source code? I couldn't find
> it in the documentation.
> >
> > For detail, I'm using postgres 11, running on Ubuntu 20.
>
> You can find the details in "src/backend/postmaster/pgarch.c".
>
> The archiver will try to archive three times (NUM_ARCHIVE_RETRIES) in an
> interval
> of one second, then back off until it receives a signal, PostgreSQL shutd
> down
> or a minute has passed.
>
> Yours,
> Laurenz Albe
> --
> Cybertec | https://www.cybertec-postgresql.com
>