From: Tom Lane <tgl@sss.pgh.pa.us>
To: Ellen Cyran <ellen@urban.csuohio.edu>
Cc: pgsql-sql@postgresql.org
Subject: Re: slow group by query
Date: Tue, 19 Nov 2002 10:21:26 -0500
Message-ID: <20977.1037719286@sss.pgh.pa.us> (raw)
In-Reply-To: <5.1.1.6.0.20021118124632.01b5dcf0@wolf.csuohio.edu>
References: <5.1.1.6.0.20021118124632.01b5dcf0@wolf.csuohio.edu>
Ellen Cyran <ellen@urban.csuohio.edu> writes:
> Is there any way to make this query faster? I have indexes on year,
> msa_code, and sic. I've also tried it with
> an index on the combined group by columns. I've made both sort_mem and
> shared_buffers bigger, but still this query
> takes 40 seconds when I select 4 msa_codes and 7 minutes when I select 40
> msa_codes.
Hm, have you vacuum analyzed lately? Those cost estimates seem awfully
low for a query that is taking 40 sec. Also, if you're using 7.2 (which
you should be ;-)) then showing EXPLAIN ANALYZE results would be more
useful than plain EXPLAIN.
regards, tom lane
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To: pgsql-sql@postgresql.org
Cc: tgl@sss.pgh.pa.us, ellen@urban.csuohio.edu
Subject: Re: slow group by query
In-Reply-To: <20977.1037719286@sss.pgh.pa.us>
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