[Pgpool-general] Online Recovery Question

[Tatsuo Ishii]

> Hi everyone, I am new to this list. I am experimenting with Pgpool-II
> for high availability and load balancing purposes.
> 
> Regarding the online recovery caveat mentioned in the manual:
> 
> "Note that there is a restriction about online recovery. If pgpool-II
> itself is installed on multiple hosts, online recovery does not work
> correctly, because pgpool-II has to stop all clients during the 2nd
> stage of online recovery. If there are several pgpool hosts, only one
> will have received the online recovery command and will block
> connections."
> 
> What should be the course of action if I run multiple pgpool-II
> instances, and I need to recover a database? For example, let my
> environment consist of multiple, redundant application servers, each
> with its own pgpool. Attached to each pgpool is the same set of
> Postgres clusters, of course. My guess would be to perform the
> following steps:
> 
> 1) Shut down all pgpool/app server pairs except for one (thus, for a
> small period of time, all connections will go through the one remaning
> pgpool/app server - this is fine for me)
> 2) Perform online recovery on the remaining pgpool
> 3) Start up all the previously-shutdown pgpools/app servers.

Yes, these are exactly the steps you need.
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese: http://www.sraoss.co.jp