Re: Index isn't used during a join.

От: Robert Creager
Тема: Re: Index isn't used during a join.
Дата: ,
Msg-id: 20060111212046.200f3e55@thunder.logicalchaos.org
(см: обсуждение, исходный текст)
Ответ на: Re: Index isn't used during a join.  (Tom Lane)
Список: pgsql-performance

Скрыть дерево обсуждения

Index isn't used during a join.  (Robert Creager, )
 Re: Index isn't used during a join.  (Michael Fuhr, )
  Re: Index isn't used during a join.  (Robert Creager, )
  Re: Index isn't used during a join.  (Robert Creager, )
   Re: Index isn't used during a join.  (Michael Fuhr, )
    Re: Index isn't used during a join.  (Michael Fuhr, )
    Re: Index isn't used during a join.  (Robert Creager, )
     Re: Index isn't used during a join.  (Robert Creager, )
      Re: Index isn't used during a join.  (Michael Fuhr, )
     Re: Index isn't used during a join.  (Tom Lane, )
      Re: Index isn't used during a join.  (Robert Creager, )

When grilled further on (Wed, 11 Jan 2006 10:33:03 -0500),
Tom Lane <> confessed:

> The planner understands about transitivity of equality, ie given a = b
> and b = c it can infer a = c.  It doesn't do any such thing for
> inequalities though, nor does it deduce f(a) = f(b) for arbitrary
> functions f.  The addition Michael suggested requires much more
> understanding of the properties of the functions in your query than
> I think would be reasonable to put into the planner.
>

OK.  I think reached a point that I need to re-organize how the data is stored,
maybe ridding myself of the schema and switching entirely to views.  At that
point, I likely could rid myself of the function (unmunge_time) I'm using, and
work with times and doy fields.

Thanks,
Rob

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