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Message-ID: <f966c2ee0803052143k4570d771o6c300647d3b987d@mail.gmail.com>
Date: Thu, 6 Mar 2008 11:13:01 +0530
From: "sathiya psql" <sathiya.psql@gmail.com>
To: pgsql-performance@postgresql.org
Subject: count * performance issue
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count(*) tooks much time...

but with the where clause we can make this to use indexing,... what where
clause we can use??

Am using postgres 7.4 in Debian OS with 1 GB RAM,

am having a table with nearly 50 lakh records,

it has more than 15 columns, i want to count how many records are there, it
is taking nearly 17 seconds to do that...

i know that to get a approximate count we can use
         SELECT reltuples FROM pg_class where relname = TABLENAME;

but this give approximate count, and i require exact count...

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count(*) tooks much time...<br><div class="gmail_quote"><br>but with the where clause we can make this to use indexing,... what where clause we can use??<br><br>Am using postgres 7.4 in Debian OS with 1 GB RAM, <br><br>am having a table with nearly 50 lakh records, <br>

<br>it has more than 15 columns, i want to count how many records are there, it is taking nearly 17 seconds to do that...<br><br>i know that to get a approximate count we can use<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; SELECT reltuples FROM pg_class where relname = TABLENAME;<br>

<br>but this give approximate count, and i require exact count...<br>
</div><br>

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