Re: Performance and IN clauses

От: Matthew Wakeling
Тема: Re: Performance and IN clauses
Дата: ,
Msg-id: alpine.DEB.1.10.0811181610310.4666@aragorn.flymine.org
(см: обсуждение, исходный текст)
Ответ на: Performance and IN clauses  ("Kynn Jones")
Ответы: Re: Performance and IN clauses  ()
Список: pgsql-performance

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Performance and IN clauses  ("Kynn Jones", )
 Re: Performance and IN clauses  (Matthew Wakeling, )
  Re: Performance and IN clauses  (, )
   Re: Performance and IN clauses  (Mark Roberts, )
    Re: Performance and IN clauses  (Tomas Vondra, )
    Re: Performance and IN clauses  (Tomas Vondra, )

On Tue, 18 Nov 2008, Kynn Jones wrote:
> Also, assuming that the optimal way to write the query depends on the length of $node_list, how can I estimate the
> "critical length" at which I should switch from one form of the query to the other?

In the past, I have found the fastest way to do this was to operate on
groups of a bit less than a thousand values, and issue one query per
group. Of course, Postgres may have improved since then, so I'll let more
knowledgable people cover that for me.

Matthew

--
 Heat is work, and work's a curse. All the heat in the universe, it's
 going to cool down, because it can't increase, then there'll be no
 more work, and there'll be perfect peace.      -- Michael Flanders


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