Hello Laurenz,
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 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
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