Fujii Masao wrote:
Hi, Heikki. Thanks for the comment!

On Thu, Nov 20, 2008 at 11:24 PM, Heikki Linnakangas
<[EMAIL PROTECTED]> wrote:
Fujii Masao wrote:
In the current Synch Rep patch, the standby cannot catch up with the
primary which has a bigger timeline.
That would only happen if you've performed an archive recovery in the
primary. If you've done PITR in the primary, I don't think there's any
guarantee that it's even possible to catch up the standby. The standby might
already have replayed a WAL file from an earlier timeline, that isn't part
of the history of the bigger timeline.

I assume the situation of making the standby (the original primary) catch up
with the primary (the original standby) after failover. Since a timeline is
incremented when a failover finishes archive recovery on a standby, the
timelines differ between two servers.

That seems like a dangerous assumption. What if the standby had fallen behind before the failover? It's not safe to failover back to the original primary in that case. We'd need some kind of safeguards against that.

--
  Heikki Linnakangas
  EnterpriseDB   http://www.enterprisedb.com

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