From: Sean Chittenden <sean@chittenden.org>
Cc: Daniel Kalchev <daniel@digsys.bg>
Cc: pgsql-hackers@postgresql.org
Subject: Re: again on index usage
Date: Mon, 7 Jan 2002 17:53:21 -0800
Message-ID: <20020107175321.C67695@ninja1.internal> (raw)
In-Reply-To: <14149.1010432467@sss.pgh.pa.us>
References: <200201071841.UAA26328@dcave.digsys.bg>
<14149.1010432467@sss.pgh.pa.us>
> It's difficult to tell from this what it thinks the selectivity of the
> ipdate index would be, since the rows estimate includes the effect of
> the ipaddr and router restrictions. What do you get from just
>
> explain
> SELECT sum(input) FROM iplog_gate200112
> WHERE
> '2001-12-01 00:00:00+02' <= ipdate AND ipdate < '2001-12-02 00:00:00+02' AND
> '2001-12-01 00:00:00+02' <= ipdate AND ipdate < '2002-01-01 00:00:00+02';
>
I don't know if this'd help, but if you're suming the data and running
this query often, see if a function index would help:
CREATE INDEX sum_input_fnc_idx ON iplog_gate200112 (sum(input));
-sc
--
Sean Chittenden
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To: pgsql-hackers@postgresql.org
Cc: sean@chittenden.org, daniel@digsys.bg
Subject: Re: again on index usage
In-Reply-To: <20020107175321.C67695@ninja1.internal>
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