[Pgpool-general] Connection made to both slave and master on SELECT, we expect only one connection (parallel_mode=fal

[Yoshiyuki Asaba]

Hi,

From: Mark F <enigma_3319 at hotmail.com>
Subject: [Pgpool-general] Connection made to both slave and master on SELECT, we expect only one connection (parallel_mode=fal
Date: Fri, 22 Feb 2008 16:53:12 -0600

> This is good, but we want to know why each request through PGPool is
> establishing a connection to both servers on each query.  We are not
> replicating select statements and have made all recommended changes
> to use a PGPool setup for load balance only.  Can someone please
> show us why PGPool is creating a connection on each database server
> for each query? 

If pgpool creates a connection for each query, the following case may
be wrong.

  postgres=# SET client_encoding TO UTF8
  postgres=# SELECT ...

Then, pgpool needs to send INSERT/UPDATE/DELETE queries to master
node in master_slave mode. So pgpool connects both servers at client
authentication.

I think there is no overhead if connection_cache is true.

Regards,
--
Yoshiyuki Asaba
y-asaba at sraoss.co.jp