Re: Consistent PITR backup

Hi Tom,

> > My idea is now: When doing a consistent PITR backup, extend the
> > documented steps between 4 (pg_stop_backup()) and 5 (wait for archived
> > WAL file) with a busy wait on pg_xlog/archive_status/*.ready files - as
> > soon as no .ready files are there anymore, the archiver has done its
> > work, and I can safely backup the archived WAL files in order to have a
> > really consistent backup.
> If the database is busy, you might never see an instant where there are
> no .ready files. Certainly it's possible that this approach will
> archive many more segments than you need.

I see - but the risk for never seeing an instant without .ready files is
relatively slow, I hope. And compared to the risk of not having a
consistent backup, I could live with having backed up more WAL files
than I actually would have needed.

> > Is that right? Or is there an easier way to do it?
> I believe the intended way to do this is to look at pg_stop_backup's
> return value to determine the last segment you need to archive.

Thank you - I saw that, but I didn't have a clue about how to determine
the WAL filename in which this segment is to be found ...

Thank you & regards,
Thomas