[pgpool-general: 6568] Re: Pgpool Info Required

Tatsuo Ishii ishii at sraoss.co.jp
Thu May 23 13:33:30 JST 2019

> Answers to some questions (just my ideas )
> 1. failover_command : this will usually be a shell script. The script will do a standby promote on new master, so there is no reason that it would fail and I believe it is over-engineering to do more than that. But since this is a script, you are free to put what you want in it : if you want to check the result of the standby promote and if it fails try on the third node, it is possible.
> 2. pgpool does not support switch-over, you would have to stop the primary postgres database and let pgpool trigger the failover and then run a pcp_recovery on the old primary postgres
> 3. The VIP point to the pgpool master not to the postgres master. So application connects to pgpool, not to postgres.
> 4. No, pgpool will not do anything when a failed standby comes back, this must be done manually or you could develop a script and schedule it via cron for example (it is a bit complex and it might be risky)
> 5. No idea, sorry
> Pierre 

Regarding 5. It's normal. Don't worry.

When a standby PostgreSQL node is added, existing connections to
Pgpool-II are kept (thus do not use the new standby for load
balacing). After the session ends, Pgpool-II child process checks
whether the failback has happend. If happend, exits itself so that new
process is spwan to reflect the fact that new standby node has been
added (thus it can use the new standby for load balancing).

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

More information about the pgpool-general mailing list