Re: Select count(*), the sequel

From: Vitalii Tymchyshyn <tivv00(at)gmail(dot)com>
To: pgsql-performance(at)postgresql(dot)org
Subject: Re: Select count(*), the sequel
Date: 2010-10-18 07:58:39
Message-ID: 4CBBFE2F.3010801@gmail.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-performance

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

In response to

Responses

Browse pgsql-performance by date

  From Date Subject
Next Message Mladen Gogala 2010-10-18 11:41:41 Re: Select count(*), the sequel
Previous Message Samuel Gendler 2010-10-18 06:13:01 Re: No hash join across partitioned tables?