Re: Automatic Client Failover

Dimitri Fontaine <dfontaine@hi-media.com> writes:
> Le 5 ao�t 08 � 01:13, Tom Lane a �crit :
>> There is one really bad consequence of the oversimplified failover
>> design that Simon proposes, which is that clients might try to fail
>> over for reasons other than a primary server failure.  (Think network
>> partition.)  You really want any such behavior to be managed
>> centrally, IMHO.

> Then, what about having pgbouncer capability into -core. This would  
> probably mean, AFAIUI,  than the listen()ing process would no longer  
> be postmaster but a specialized one,

Huh?  The problem case is that the primary server goes down, which would
certainly mean that a pgbouncer instance on the same machine goes with
it.  So it seems to me that integrating pgbouncer is 100% backwards.

Failover that actually works is not something we can provide with
trivial changes to Postgres.  It's really a major project in its
own right: you need heartbeat detection, STONITH capability,
IP address redirection, etc.  I think we should be recommending
external failover-management project(s) instead of offering a
half-baked home-grown solution.  Searching freshmeat for "failover"
finds plenty of potential candidates, but not having used any of
them I'm not sure which are worth closer investigation.
        regards, tom lane