Tom Lane wrote:
> Bruce Momjian <pgman@candle.pha.pa.us> writes:
> >> Does anyone know what the major barriers to infinite log replay are in
> >> PostgreSQL? I'm trying to look for everything that might need to be
> >> changed outside xlog.c, but surely this has come up before. Searching
> >> the archives hasn't revealed much.
>
> > This has been brought up. Could we just save WAL files and get replay?
> > I believe some things have to be added to WAL to allow this, but it
> > seems possible.
>
> The Red Hat group has been looking at this somewhat; so far there seem
> to be some minor tweaks that would be needed, but no showstoppers.
Good.
> > Somehow you would need a tar-type
> > backup of the database, and with a running db, it is hard to get a valid
> > snapshot of that.
>
> But you don't *need* a "valid snapshot", only a correct copy of
> every block older than the first checkpoint in your WAL log series.
> Any inconsistencies in your tar dump will look like repairable damage;
> replaying the WAL log will fix 'em.
Yes, my point was that you need physical file backups, not pg_dump, and
you have to be tricky about the files changing during the backup. You
_can_ work around changes to the files during backup.
-- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610)
853-3000+ If your life is a hard drive, | 830 Blythe Avenue + Christ can be your backup. | Drexel Hill,
Pennsylvania19026
/usr/local/bin/mime: cannot create /dev/ttyp3: permission denied
