[Pgpool-hackers] proposal for new feature

[Tatsuo Ishii]

> Hi all,
> 
> I'm a developer of the PGCluster which is a multi-master synchronous replication tool for PogstreSQL.
> I have used pgpool as a loadbalancer of PGCluster for a long time (about eight years).

Welcome Mitani!

> I would like to propose new features for pgpool-II to bolster an availability.
>
> In order to prevent single point of failure, two or more pgpool sets should be put in a system. In this case, there are two type of composition. 
> (1) Single master and multi slave composition
> If the master pgpool failed, the slave pgpool might take over it.
> I know there are some tools which is designed to build redundant system like a Heartbeat, DRBD and Lifekeeper etc. However, these tools are not so easy to build up. And these are not enouth for database redundancy I think.
> If pgpool-II has this function in it self, user might be pleased to use it.
> (2) Multi master composition 
> I know that pgpool-II can be used like a multi master composition.
> However, if one pgpool execute online backup, other pgpools are not block  sessions.
> I think that it needs a cooperate action for online backup.
> 
> I'll create some patches within a few monthes if nobody oppesed it.
> I would like to have a comment about it.

All sounds great to me. In the mean time I'm interested in how do you
design a communication infrastracture between mutiple pgpool instances
in #1. I'm looking forward to hearing more details from you.
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese: http://www.sraoss.co.jp