[pgpool-general: 3957] Re: How promote pgpool II a slave among many slaves

[Tatsuo Ishii]

> Recently, I have been working in a project and I have a doubt about how
> promote pgpool II a slave to master (in the case that you have more than
> one slave). Is there any rule or parameter?

No. It totally depends on how you write the failover script.

For example, pgpool_setup, a testing tool coming with pgpool-II source
code, will promote the new master node, which is live and the youngest
DB node. Suppose there are 4 DB nodes 0: primary node, 1: standby,
2:standby, 3:standby.

1) If node 0 goes down, node 1 is promoted because 1 is live and the
younguest. Now we have:

	   0: down
	   1: primary
	   2: standby
	   3: standby

2) If node 1 goes down, node 2 is promoted because 1 is live and the
younguest. Now we have:

	   0: down
	   1: down
	   2: primary
	   3: standby

This is just an example. You could think of your own algorithm.

Best regards,
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese:http://www.sraoss.co.jp