Re: Trivial query, large query, but very sad results.

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Alexander Haväng <eel(at)musiknet(dot)se>
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: Trivial query, large query, but very sad results.
Date: 2002-04-02 15:41:38
Message-ID: 24976.1017762098@sss.pgh.pa.us
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=?iso-8859-1?Q?Alexander_Hav=E4ng?= <eel(at)musiknet(dot)se> writes:
> I'm using postgresql 7.1.3 (linux 2.4.17, 2*1.13 Mhz SMP), and I've created a table with 10 million rows.

> When I do a query, say,
> SELECT count(id) FROM bigtable WHERE somestring='something';

What's the query plan (see EXPLAIN)? What fraction of the rows are
actually selected by that WHERE clause? Is there anything else
going on in Postgres?

7.1.* is known to have performance problems on SMP machines, but I do
not think the problems affect a single-query situation. On the other
hand, if you are running multiple queries in parallel, that could
explain your poor results. Try 7.2...

regards, tom lane

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