Re: Cascading replication and recovery_target_timeline='latest' - Mailing list pgsql-hackers

From Heikki Linnakangas
Subject Re: Cascading replication and recovery_target_timeline='latest'
Date
Msg-id 5046844F.6000800@iki.fi
Whole thread Raw
In response to Re: Cascading replication and recovery_target_timeline='latest'  (Dimitri Fontaine <dimitri@2ndQuadrant.fr>)
Responses Re: Cascading replication and recovery_target_timeline='latest'  (Dimitri Fontaine <dimitri@2ndQuadrant.fr>)
List pgsql-hackers
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.
>
> It looks to me like a bug fix that also applies to non cascading
> situation. Is that right?

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.

- Heikki



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