Clustering (was Re: Optimizing Query)

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От Mathijs Brands
Тема Clustering (was Re: Optimizing Query)
Дата
Msg-id 20010305230355.B22983@ilse.nl
обсуждение исходный текст
Ответ на Re: Optimizing Query  (Bruce Momjian <pgman@candle.pha.pa.us>)
Список pgsql-sql
On Mon, Mar 05, 2001 at 04:45:47PM -0500, Bruce Momjian allegedly wrote:
> Yes.
> 
> > On Mon, Mar 05, 2001 at 04:07:57PM -0500, Bruce Momjian allegedly wrote:
> > > Have you tried VACUUM ANALYZE and CLUSTER?
> > 
> > I assume CLUSTER still drops all indexes except the one you're clustering
> > on?
> > 
> > Mathijs

So running cluster on the words table (which is indexed with a seperate index
on each of the two fields) would probably decrease performance by getting rid
of one index without warning (the one NOT specified in the cluster command)?

How useful is clustering with pgsql when in a lot of situations systems have
enough memory to have the filesystem subsystem cache most or all index data?
Seek times shouldn't be an issue in such a situation, since the index doesn't
have to be read.

Just wondering,

Mathijs
-- 
It's not that perl programmers are idiots, it's that the language
rewards idiotic behavior in a way that no other language or tool has
ever done.                                                   Erik Naggum


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