From: Yves Vindevogel <yves.vindevogel@implements.be>
To: pgsql-performance@postgresql.org
Subject: Fwd: Updates on large tables are extremely slow
Date: Mon, 13 Jun 2005 17:49:47 +0200
Message-ID: <6243ad910c02150d526b7b32d4cfef9d@implements.be> (raw)
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 !
>
> On 13 Jun 2005, at 16:32, Tom Lane wrote:
>
>> Yves Vindevogel <yves.vindevogel@implements.be> writes:
>>> rvponp=3D# vacuum verbose tblPrintjobs ;
>>> INFO: vacuuming "public.tblprintjobs"
>>> [ twenty-one different indexes on one table ]
>>
>> Well, there's your problem. You think updating all those indexes is
>> free? It's *expensive*. Heed the manual's advice: avoid creating
>> indexes you are not certain you need for identifiable commonly-used
>> queries.
>>
>> (The reason delete is fast is it doesn't have to touch the indexes ...
>> the necessary work is left to be done by VACUUM.)
>>
>> regards, tom lane
>>
>>
> Met vriendelijke groeten,
> Bien à vous,
> Kind regards,
>
> Yves Vindevogel
> Implements
>
>
>
> Mail: yves.vindevogel@implements.be - Mobile: +32 (478) 80 82 91
>
> Kempische Steenweg 206 - 3500 Hasselt - Tel-Fax: +32 (11) 43 55 76
>
> Web: http://www.implements.be
>
> First they ignore you. Then they laugh at you. Then they fight you.
> Then you win.
> Mahatma Ghandi.
>
Met vriendelijke groeten,
Bien à vous,
Kind regards,
Yves Vindevogel
Implements
Mail: yves.vindevogel@implements.be - Mobile: +32 (478) 80 82 91
Kempische Steenweg 206 - 3500 Hasselt - Tel-Fax: +32 (11) 43 55 76
Web: http://www.implements.be
First they ignore you. Then they laugh at you. Then they fight you.
Then you win.
Mahatma Ghandi.
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Cc: yves.vindevogel@implements.be
Subject: Re: Fwd: Updates on large tables are extremely slow
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