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.

If you have ever set hot_standby=on in your standby server, running one of the affected versions, you're at risk. The standby might be corrupt, and should be rebuild from a base backup. The higher the transaction rate in the master, the higher the risk.

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

- Heikki


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