Re: restoring wal archive and pg_xlog dir - Mailing list pgsql-admin

From Tom Lane
Subject Re: restoring wal archive and pg_xlog dir
Date
Msg-id 7197.1119551082@sss.pgh.pa.us
Whole thread Raw
In response to restoring wal archive and pg_xlog dir  (Jeff Frost <jeff@frostconsultingllc.com>)
Responses Re: restoring wal archive and pg_xlog dir  (Jeff Frost <jeff@frostconsultingllc.com>)
List pgsql-admin
Jeff Frost <jeff@frostconsultingllc.com> writes:
> If the system will use the files in the archive in preference to the ones in
> pg_xlog, how can this actually happen if it will not overwrite the contents of
> pg_xlog?

Segment files pulled from the archive are saved using temporary file
names (and then deleted after being replayed).  For obvious safety
reasons, we try never to overwrite any xlog file in either the archive
or local storage.

> I also noticed that if there is not at least one wal archive available in
> the archive or the pg_xlog dir, the restore errors out and exits.  So the
> base backup is really not complete without at least one wal archive
> following it.  Is this by design?

Certainly.  If you don't have wal data spanning the entire time that the
base backup is being taken, the backup is useless because there's no way
to make it consistent.

            regards, tom lane

pgsql-admin by date:

Previous
From: Jeff Frost
Date:
Subject: restoring wal archive and pg_xlog dir
Next
From: Jeff Frost
Date:
Subject: Re: restoring wal archive and pg_xlog dir