Re: anti-join chosen even when slower than old plan

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От Bruce Momjian
Тема Re: anti-join chosen even when slower than old plan
Дата
Msg-id 201101270140.p0R1eoH20105@momjian.us
обсуждение исходный текст
Ответ на Re: anti-join chosen even when slower than old plan  (Robert Haas <robertmhaas@gmail.com>)
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Robert Haas wrote:
> On Thu, Jan 20, 2011 at 4:17 AM, C?dric Villemain
> <cedric.villemain.debian@gmail.com> wrote:
> >>> I think his point is that we already have a proven formula
> >>> (Mackert-Lohmann) and shouldn't be inventing a new one out of thin air.
> >>> The problem is to figure out what numbers to apply the M-L formula to.
> >>>
> >>> I've been thinking that we ought to try to use it in the context of the
> >>> query as a whole rather than for individual table scans; the current
> >>> usage already has some of that flavor but we haven't taken it to the
> >>> logical conclusion.
> >>
> >> Is there a TODO here?
> >
> > it looks like, yes.
>
> "Modify the planner to better estimate caching effects"?

Added to TODO.

--
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

  + It's impossible for everything to be true. +

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