Simon Riggs wrote:
On Thu, 2009-05-07 at 17:54 +0300, Heikki Linnakangas wrote:
Simon Riggs wrote:
A more useful thing might be to do an xlog switch before we do the
shutdown checkpoint at end of recovery. That gives the same sequence of
actions without modifying the existing sequence of activities for
backups, which is delicate enough for me to not want to touch it.
Hmm, yeah should work as well. I find the recovery sequence to be even
more delicate, though, than pg_start_backup(). I think you'd need to
write the XLOG switch record using the old timeline ID, as we currently
require that the timeline changes only at a shutdown checkpoint record.
That's not hard, but does make me a bit nervous.
Yes, you're right about the delicacy of all of this so both suggestions
sound kludgey - the problem is to do with timelines not with sequencing
of checkpoints and log switches. The problem is Mikael deleted the
history file and he shouldn't have done that.
I don't see any user error here. What he did was:
1. Restore from backup A
2. Clear old WAL archive
3. pg_start_backup() + tar all but pg_xlog + pg_stop_backup();
4. Restore new backup B
There's no history file in the archive because it was cleared in step 2.
There's nothing wrong with that; you only need to retain WAL files from
the point that you call pg_start_backup(). There's no history file
either in the tar, because pg_xlog was not tarred as we recommend in the
manual.
--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com
--
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers
