Re: [ADMIN] poor performance in migrated database

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От Carlos Lopez
Тема Re: [ADMIN] poor performance in migrated database
Дата
Msg-id 20041109145631.86002.qmail@web52710.mail.yahoo.com
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Ответ на Re: [ADMIN] poor performance in migrated database  (Tom Lane <tgl@sss.pgh.pa.us>)
Список pgsql-performance
Dear Tom,
thanks for your information.
Where can I learn more about the explain and analyze??
One view that is giving a lot of problems is vkardex_3
which is used most of the time...
The explain analyze I sent is one of the views that
conform this one.

Thanks in advance.
Carlos Lopez Linares


--- Tom Lane <tgl@sss.pgh.pa.us> wrote:

> Carlos Lopez <chlopezl@yahoo.com> writes:
> > This is one of the queries that work,and is the
> first
> > in a 4 level nested query....
>
> Do you really need UNION (as opposed to UNION ALL)
> in this query?
> The EXPLAIN shows that almost half the runtime is
> going into the
> sort/uniq to eliminate duplicates ... and according
> to the row
> counts, there are no duplicates, so it's wasted
> effort.
>
> I looked at your schema and saw an awful lot of
> SELECT DISTINCTs
> that looked like they might not be necessary, too.
> But I'm not
> willing to crawl through 144 views with no
> information about
> which ones are causing you problems.  What's a
> typical query
> that you are unsatisfied with the performance of?
>
>             regards, tom lane
>


=====
___
Ing. Carlos L�pez Linares
IT Consultant
Quieres aprender linux?
visita http://www.aprende-linux.com.sv

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