From: Stephen Byers <stephenabyers@yahoo.com>
To: Steinar H. Gunderson <sgunderson@bigfoot.com>
To: pgsql-performance@postgresql.org
Subject: Re: why is bitmap index chosen for this query?
Date: Thu, 18 May 2006 09:41:23 -0700 (PDT)
Message-ID: <20060518164123.98856.qmail@web30710.mail.mud.yahoo.com> (raw)
In-Reply-To: <20060518155906.GA6909@uio.no>
"Steinar H. Gunderson" <sgunderson@bigfoot.com> wrote:
It sounds like PostgreSQL badly overestimates the cost of the index scan.
Does the table perchance fit completely into memory, without
effective_cache_size indicating that?
Don't know the exact way to answer your question, but my initial instinct is "no way."
select pg_relation_size('packets');
pg_relation_size
------------------
19440115712
19GB. So it's a big table. The query I submitted earlier returns about 13M rows and the table currently has about 38M rows.
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To: pgsql-performance@postgresql.org
Cc: stephenabyers@yahoo.com, sgunderson@bigfoot.com
Subject: Re: why is bitmap index chosen for this query?
In-Reply-To: <20060518164123.98856.qmail@web30710.mail.mud.yahoo.com>
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