Subject: Re: Updates on large tables are extremely slow
From: Rod Taylor <pg@rbt.ca>
To: Yves Vindevogel <yves.vindevogel@implements.be>
Cc: pgsql-performance@postgresql.org
In-Reply-To: <93fcaa35413e2059526ab3aa562a17dd@implements.be>
References: <6243ad910c02150d526b7b32d4cfef9d@implements.be>
	<42ADAE10.6050204@archonet.com>
	<93fcaa35413e2059526ab3aa562a17dd@implements.be>
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Date: Mon, 13 Jun 2005 12:53:19 -0400
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> Ok, if all 21 are affected, I can understand the problem.
> But allow me to say that this is a "functional error"

It's a choice between total throughput on a high load, high connection
basis (MVCC dramatically wins here), versus a single user, low load
scenario (MS Access is designed for this).

Believe me when I say that a lot of people have spent a lot of time
explicitly making the system work that way.

> On 13 Jun 2005, at 18:02, Richard Huxton wrote:
> 
>         Yves Vindevogel wrote:
>                 I forgot cc
>                 Begin forwarded message:
>                         From: Yves Vindevogel
>                         <yves.vindevogel@implements.be>
>                         Date: Mon 13 Jun 2005 17:45:19 CEST
>                         To: Tom Lane <tgl@sss.pgh.pa.us>
>                         Subject: Re: [PERFORM] Updates on large tables
>                         are extremely slow
>                         
>                         Yes, but if I update one column, why should PG
>                         update 21 indexes ?
>                         There's only one index affected !
>         
>         No - all 21 are affected. MVCC creates a new row on disk.
>         
>         -- 
>           Richard Huxton
>           Archonet Ltd
>         
>         
> Met vriendelijke groeten,
> Bien à vous,
> Kind regards,
> 
> Yves Vindevogel
> Implements
> 
> 
> 
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