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Message-ID: <4CBBFE2F.3010801@gmail.com>
Date: Mon, 18 Oct 2010 10:58:39 +0300
From: Vitalii Tymchyshyn <tivv00@gmail.com>
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To: pgsql-performance@postgresql.org
Subject: Re: Select count(*), the sequel
References: <4CB9D82F.9040505@gmail.com>
In-Reply-To: <4CB9D82F.9040505@gmail.com>
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16.10.10 19:51, Mladen Gogala написав(ла):
> There was some doubt as for the speed of doing the select count(*) in 
> PostgreSQL and Oracle.
> To that end, I copied the most part of the Oracle table I used before 
> to Postgres. Although the copy
> wasn't complete, the resulting table is already significantly larger 
> than the table it was copied from. The result still shows that Oracle 
> is significantly faster:

Hello.

Did you vacuum postgresql DB before the count(*). I ask this because 
(unless table was created & loaded in same transaction) on the first 
scan, postgresql has to write hint bits to the whole table. Second scan 
may be way faster.

Best regards, Vitalii Tymchyshyn