Re: BUG in pg_autovacuum - with patch

Karl Denninger wrote:

>I have a process which does backups by mounting a disk into a RAID array,
>allowing it to sync, then it must stop the database before detaching it so
>as to insure that the DBMS is consistent on the backup disk.
>
>Once detached, Postgres must be restarted, of course......
>
>This process is MUCH faster than dumping the disks to tape and results in a
>bootable backup volume - the latter is of great value for disaster recovery!
>
>

The problem is that if pg_autovacuum exits and then is relaunched, it
doesn't remember any of it's state information from when it last
exited. So if you are stopping and starting autovacuum one a day, it
will be less effective. If you have some very active tables that
autovacuum will vacuum several times a day then I can still see it's
usefullness, but it's never going to vacuum a table that doesn't have
enough activity to cause a vacuum in one day.

Anyway, if pg_autovacuum is causing problems for cron I'm sure we would
still benefit from this patch. However, while I claim no expertise
related to detaching from the console, I will say that I copied the code
detach code directly from postgresql itself, so I would have thought it
was OK. Can someone more informed than I take a look at this patch?

Thanks,

Matthew