Playing with Elephants ~PostgreSQL and Pgpool-II~

  Pgpool-II is a PostgreSQL cluster management tool. In this post I will explain how to retrieve the cluster statistics from Pgpool-II. There are 3 ways to retrieve cluster statistics: use SHOW SQL commands          The SHOW commands can be issued inside a SQL session. They are not forwarded to PostgreSQL and only processed by Pgpool-II.  use PCP commands          Since PCP commands can be executed via network, you are able to operate Pgpool-II from remote servers using PCP commands. use pgpool_adm extension            Pgpool_adm is an extension to allow to access to PCP commands. The advantage of using pgpool_adm is that you can specify specific conditions to retrieve the required data. To use pgpool_adm you need to install pgpool-II-pg*-extensions package and execute " CREATE EXTENSION pgpool_adm " on PostgreSQL servers.   Next, let's see how to retrieve Pgpool-II's statistics. Backend nodes statistics To retrieve backend nodes statistics, you can execute the fol