Message-ID: <514CC98E.4050903@agliodbs.com>
Date: Fri, 22 Mar 2013 14:13:50 -0700
From: Josh Berkus <josh@agliodbs.com>
Organization: PostgreSQL Experts Inc.
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To: pgsql-performance@postgresql.org
Subject: Re: Performance of query
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On 03/22/2013 12:46 PM, Cindy Makarowsky wrote:
> I've tried playing around with the settings in the config file for
> shared_buffers, work_mem, etc restarting Postgres each time and nothing
> seems to help.

Well, you're summarizing 55 million rows on an unindexed table:

"        ->  Seq Scan on busbase  (cost=0.00..6378172.28 rows=55402728
width=7) (actual time=0.004..250046.673 rows=60057057 loops=1)"

... that's where your time is going.

My only suggestion would be to create a composite index which matches
the group by condition on table1, and vacuum freeze the whole table so
that you can use index-only scan on 9.2.

-- 
Josh Berkus
PostgreSQL Experts Inc.
http://pgexperts.com


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