From: Tom Lane <tgl@sss.pgh.pa.us>
To: Jeffrey Tenny <jeffrey.tenny@comcast.net>
Cc: Jim C. Nasby <jnasby@pervasive.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: performance question (something to do w/ parameterized
Date: Mon, 08 May 2006 16:49:58 -0400
Message-ID: <29684.1147121398@sss.pgh.pa.us> (raw)
In-Reply-To: <445FAB2A.9050401@comcast.net>
References: <445F7FF8.6070707@comcast.net>
<20060508173812.GW99570@pervasive.com>
<445F9F6B.9040200@comcast.net>
<29345.1147118920@sss.pgh.pa.us>
<445FAB2A.9050401@comcast.net>
Jeffrey Tenny <jeffrey.tenny@comcast.net> writes:
> I dropped the multicolumn index 'testindex2', and a new explain analyze
> looks like this:
> Sort (cost=35730.71..35768.28 rows=1503 width=16) (actual
> time=962.555..964.467 rows=677 loops=1)
> Sort Key: f, c
> -> Seq Scan on x (cost=0.00..34937.60 rows=1503 width=16) (actual
> time=5.449..956.594 rows=677 loops=1)
> Filter: ((f = 1) OR (f = 2) OR (f = 3) ...
> Turning on the server debugging again, I got roughly identical
> query times with and without the two column index.
That's good, actually, seeing that the planner thinks they're close to
the same speed too. Now try "set enable_seqscan = off" to see if you
can force the multi-index-scan plan to be chosen, and see how that does.
regards, tom lane
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To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, jeffrey.tenny@comcast.net, jnasby@pervasive.com
Subject: Re: performance question (something to do w/ parameterized
In-Reply-To: <29684.1147121398@sss.pgh.pa.us>
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