Re: Cascading replication and recovery_target_timeline='latest'

Heikki Linnakangas <hlinnaka@iki.fi> writes:
> On 04.09.2012 03:02, Dimitri Fontaine wrote:
>> Heikki Linnakangas<hlinnaka@iki.fi>  writes:
>>> Hmm, I was thinking that when walsender gets the position it can send the
>>> WAL up to, in GetStandbyFlushRecPtr(), it could atomically check the current
>>> recovery timeline. If it has changed, refuse to send the new WAL and
>>> terminate. That would be a fairly small change, it would just close the
>>> window between requesting walsenders to terminate and them actually
>>> terminating.
>
> No, only cascading replication is affected. In non-cascading situation, the
> timeline never changes in the master. It's only in cascading mode that you
> have a problem, where the standby can cross timelines while it's replaying
> the WAL, and also sending it over to cascading standby.

It seems to me that it applies to connecting a standby to a newly
promoted standby too, as the timeline did change in this case too.

Regards,
-- 
Dimitri Fontaine
http://2ndQuadrant.fr     PostgreSQL : Expertise, Formation et Support