Re: Forcing current WAL file to be archived

Simon Riggs wrote:
> On Tue, 2006-07-25 at 11:31 -0400, Tom Lane wrote:
> > Bruce Momjian <bruce(at)momjian(dot)us> writes:
> > > For example, if you do pg_stop_backup(), in what cases would you not
> > > also call pg_finish_wal_segment()? I can't think of one.
> >
> > I can't see why you would need to, unless your intention is not to run
> > PITR at all but only to make a filesystem backup instead of using
> > pg_dump.
>
> If thats all you want you can set
> archive_command = 'echo %f %p > /dev/null'

Uh, what good is a file system backup without the WAL files modified
during the backup?

> > Normally you'd be running a continuing archival process and
> > there's no particular need to force the current WAL segment off to
> > archive at that exact instant.
>
> That's exactly the point of contention. When we originally completed
> PITR we thought that was acceptable. It isn't and many people have stuck
> pins in effigies of me since then. :-/
>
> > My point here is that forcing the current segment to archive is a
> > function of whatever your continuous-archiving process is, and it's
> > not necessarily tied to backups. We should not prejudge when people
> > want that fairly-expensive function to be invoked.
>
> The point is until that last WAL file is backed up, the whole backup is
> useless. It isn't good policy to have a backup's value be contingent on
> some future event.

Good analysis.

--
Bruce Momjian bruce(at)momjian(dot)us
EnterpriseDB http://www.enterprisedb.com

+ If your life is a hard drive, Christ can be your backup. +