Fwd: Updates on large tables are extremely slow

I forgot cc

Begin forwarded message:

> From: Yves Vindevogel <yves(dot)vindevogel(at)implements(dot)be>
> Date: Mon 13 Jun 2005 17:45:19 CEST
> To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)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(dot)vindevogel(at)implements(dot)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
>