Re: Data corruption issues using streaming replication on 9.0.14/9.2.5/9.3.1

On 2013-11-21 23:02:29 +0200, Heikki Linnakangas wrote:
> On 21.11.2013 22:53, Andres Freund wrote:
> >On 2013-11-21 12:51:17 -0800, Josh Berkus wrote:
> >>On 11/21/2013 12:46 PM, Andres Freund wrote:
> >>>The problem is starting with hot_standby=on on a system with
> >>>recovery.conf present. It is independent of whether you use streaming
> >>>replication, archive based recovery, or just shutdown the server and
> >>>manually copy xlog segments there.
> >>>As long as hot_standby=on, and recovery.conf is present you can hit the
> >>>bug.
> >>
> >>Oh, aha. There have to be some transactions which are awaiting
> >>checkpoint, though, correct? As in, if there's no activity on the
> >>master, you can't trigger the bug?
> >
> >Correct. Also, if you *start* at such a checkpoint you're not vulnerable
> >until the standby is restarted.
>
> Keep in mind that autovacuum counts as "activity" in this case. If you're
> unlucky, that is. It's next to impossible to determine after-the-fact if
> there has been activity in the master that might've caused problems.

Well, in that case you're going to "just" loose the
pg_database/pg_class/stats updates from analyze/vacuum. That's annoying,
but not too bad.

> I wouldn't try to narrow it down any further than that, it gets too
> complicated.

Yes.

Greetings,

Andres Freund

--
Andres Freund http://www.2ndQuadrant.com/
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