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Message-ID: <9e4684ce0510080344v1dfa36f7nea19ddb1ad38f652@mail.gmail.com>
Date: Sat, 8 Oct 2005 12:44:09 +0200
From: hubert depesz lubaczewski <depesz@gmail.com>
Reply-To: hubert depesz lubaczewski <depesz@gmail.com>
To: Cestmir Hybl <cestmirl@freeside.sk>
Subject: Re: count(*) using index scan in "query often,
	update rarely" environment
Cc: pgsql-performance@postgresql.org
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On 10/7/05, Cestmir Hybl <cestmirl@freeside.sk> wrote:
>
> No, I can't speed-up evaluation of generic "count(*) where ()" queries
> this way.
>

no you can't speed up generic where(), *but* you can check what are the mos=
t
common "where"'s (like usually i do where on one column like:
select count(*) from table where some_particular_column =3D 'some value';
where you can simply make the trigger aware of the fact that it should coun=
t
based on value in some_particular_column.
works good enough for me not to look for alternatives.

depesz

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On 10/7/05, <b class=3D"gmail_sendername">Cestmir Hybl</b> &lt;<a href=3D"m=
ailto:cestmirl@freeside.sk">cestmirl@freeside.sk</a>&gt; wrote:<div><span c=
lass=3D"gmail_quote"></span><blockquote class=3D"gmail_quote" style=3D"bord=
er-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-l=
eft: 1ex;">
<div><font face=3D"Arial" size=3D"2">No, I can't speed-up evaluation of gen=
eric=20
&quot;count(*) where ()&quot; queries this way.</font></div></blockquote></=
div><br>
no you can't speed up generic where(), *but* you can check what are the
most common &quot;where&quot;'s (like usually i do where on one column like=
:<br>
select count(*) from table where some_particular_column =3D 'some value';<b=
r>
where you can simply make the trigger aware of the fact that it should coun=
t based on value in some_particular_column.<br>
works good enough for me not to look for alternatives.<br>
<br>
depesz<br>
<br>
<br>

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