From: CS DBA <cs_dba@consistentstate.com>
To: pgsql-performance@postgresql.org
Subject: Increased shared_buffer setting = lower hit ratio ?
Date: Thu, 13 Nov 2014 16:09:18 -0700
Message-ID: <54653A1E.3050805@consistentstate.com> (raw)
List-Unsubscribe: <mailto:majordomo@postgresql.org?body=unsub%20pgsql-performance>
All;
We have a large db server with 128GB of ram running complex functions.
with the server set to have the following we were seeing a somewhat low
hit ratio and lots of temp buffers
shared_buffers = 18GB
work_mem = 75MB
effective_cache_size = 105GB
checkpoint_segments = 128
when we increased the values to these not only did the hit ratio drop
but query times are now longer as well:
shared_buffers = 28GB
work_mem = 150MB
effective_cache_size = 105GB
checkpoint_segments = 256
This does not seem to make sense to me, anyone have any thoughts on why
more memory resources would cause worse performance?
Thanks in advance
--
Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-performance
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-performance@postgresql.org
Cc: cs_dba@consistentstate.com
Subject: Re: Increased shared_buffer setting = lower hit ratio ?
In-Reply-To: <54653A1E.3050805@consistentstate.com>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox