Re: View performance

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От Bruno Wolff III
Тема Re: View performance
Дата
Msg-id 20021226203656.GB22984@wolff.to
обсуждение исходный текст
Ответ на Re: View performance  (Tom Lane <tgl@sss.pgh.pa.us>)
Ответы Re: View performance
Список pgsql-performance
On Thu, Dec 26, 2002 at 14:42:39 -0500,
  Tom Lane <tgl@sss.pgh.pa.us> wrote:
>
> which means that views using subselects in their targetlists will not be
> flattened into the calling query in 7.3.1.  This is not real desirable,
> but I see no other short-term fix.

Thanks for the explaination.

> In the particular case, your view definition seemed mighty inefficient
> anyway (it must recompute the subselects for each column retrieved from
> the view) so I think your rewrite is a good change.

I was naively expecting that the planner would notice the common subexpressions
and only compute them once.

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