From: "Carlo Stonebanks" <stonec.register@sympatico.ca>
Subject: default_statistics_target
Date: Sun, 14 Mar 2010 19:27:57 -0400
Organization: Hub.Org Networking Services
Lines: 20
Message-ID: <hnjrcs$2trl$1@news.hub.org>
Mime-Version: 1.0
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
	reply-type=original
Content-Transfer-Encoding: 7bit
To: pgsql-performance@postgresql.org

Hi people,

The whole topic of messing with stats makes my head spin but I am concerned 
about some horridly performing queries that have had bad rows estimates and 
others which always choose seq scans when indexes are available. Reading up 
on how to improve planner estimates, I have seen references to 
default_statistics_target being changed from the default of 10 to 100.

Our DB is large, with thousands of tables, but the core schema has about 100 
tables and the typical row counts are in the millions of rows for the whole 
table. We have been playing endless games with tuning this server - but with 
all of the suggestions, I don't think the issue of changing 
default_statistics_target has ever come up. Realizing that there is a 
performance hit associated with ANALYZE, are there any other downsides to 
increasing this value to 100, and is this a common setting for large DBs?

Thanks,

Carlo