Re: pg_upgrade and epoch

On Tue, Apr 22, 2014 at 6:33 PM, Sergey Burladyan <eshkinkot@gmail.com> wrote:
> Current pg_upgrade copy XID into new cluster, but not it epoch. Why?
>
> Without epoch from old cluster txid_current() in upgraded database return
> lower value than before upgrade. This break, for example, PgQ and it must
> be fixed by hand after upgrade with pg_resetxlog.
>
> PS: see
> http://lists.pgfoundry.org/pipermail/skytools-users/2014-April/001812.html

BTW, I didn't manage to make a test case yet. Recently, when I was
migrating several servers to skytools3 and upgrading from 9.0 to 9.2,
I noticed that epoch was copied, timeline id was >0 after upgrade, but
skytools3 sometimes still didn't like it. Also note "sometimes" here,
so in some cases everything was okay, but in some it wasn't. I still
can't explain this, but incrementing timeline id always helped.

-- 
Kind regards,
Sergey Konoplev
PostgreSQL Consultant and DBA

http://www.linkedin.com/in/grayhemp
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