Re: Consistent PITR backup

Thomas Karcher <thkarcher(at)gmx(dot)de> writes:
> 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.

> 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.

regards, tom lane