From: Markus Schaber <schabi@logix-tt.com>
To: pgsql-performance@postgresql.org
Subject: Re: Poor performance on seq scan
Date: Mon, 18 Sep 2006 10:22:00 +0200
Message-ID: <450E5728.7000802@logix-tt.com> (raw)
In-Reply-To: <200609121410.02710.P.Kolaczkowski@elka.pw.edu.pl>
References: <450684EC.4090304@designaproduct.biz>
<4506902C.7090407@enterprisedb.com>
<200609121410.02710.P.Kolaczkowski@elka.pw.edu.pl>
Hi, Piotr,
Piotr Kołaczkowski wrote:
> Why match rows from the heap if ALL required data are in the index itself?
> Why look at the heap at all?
Because the index does not contain any transaction informations, so it
has to look to the heap to find out which of the rows are current.
This is one of the more debated points in the PostgreSQL way of MVCC
implementation.
Markus
--
Markus Schaber | Logical Tracking&Tracing International AG
Dipl. Inf. | Software Development GIS
Fight against software patents in Europe! www.ffii.org
www.nosoftwarepatents.org
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To: pgsql-performance@postgresql.org
Cc: schabi@logix-tt.com
Subject: Re: Poor performance on seq scan
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