Re: performance with query

От: Kevin Grittner
Тема: Re: performance with query
Дата: ,
Msg-id: 4A3A552E0200002500027DB3@gw.wicourts.gov
(см: обсуждение, исходный текст)
Ответ на: Re: performance with query  (Tom Lane)
Список: pgsql-performance

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performance with query  (Alberto Dalmaso, )
 Re: performance with query  (Joshua Tolley, )
 Re: performance with query  ("Kevin Grittner", )
 Re: performance with query  (Alberto Dalmaso, )
  Re: performance with query  (Matthew Wakeling, )
   Re: performance with query  (Alberto Dalmaso, )
    Re: performance with query  (Tom Lane, )
     Re: performance with query  (Alberto Dalmaso, )
      Re: performance with query  (Tom Lane, )
      Re: performance with query (OT)  ("Albe Laurenz", )
    Re: performance with query  ("Kevin Grittner", )
  Re: performance with query  ("Kevin Grittner", )
   Re: performance with query  (Alberto Dalmaso, )
    Re: performance with query  ("Kevin Grittner", )
    Re: performance with query  ("Kevin Grittner", )
     Re: performance with query  (Alberto Dalmaso, )
      Speeding up a query.  ("Hartman, Matthew", )
       Re: Speeding up a query.  (Anthony Presley, )
        Re: Speeding up a query.  ("Hartman, Matthew", )
       Re: Speeding up a query.  ("Albe Laurenz", )
        Re: Speeding up a query.  (Grzegorz Jaśkiewicz, )
       Re: Speeding up a query.  (Alberto Dalmaso, )
        Re: Speeding up a query.  ("Kevin Grittner", )
        Re: Speeding up a query.  (Tom Lane, )
       Re: Speeding up a query.  (Merlin Moncure, )
        Re: Speeding up a query.  ("Hartman, Matthew", )
       Re: Speeding up a query.  ("Hartman, Matthew", )
       Re: Speeding up a query.  (Simon Riggs, )
        Re: Speeding up a query.  ("Hartman, Matthew", )
 Re: performance with query  (Alberto Dalmaso, )
 Re: performance with query  (Alberto Dalmaso, )
  Re: performance with query  ("Kevin Grittner", )
   Re: performance with query  (Alberto Dalmaso, )
    Re: performance with query  ("Kevin Grittner", )
     Re: performance with query  (Alberto Dalmaso, )
      Re: performance with query  ("Kevin Grittner", )
       Re: performance with query  (Tom Lane, )
        Re: performance with query  ("Kevin Grittner", )

Tom Lane <> wrote:
> "Kevin Grittner" <> writes:
>> With all the optimizer options on, and the from_collapse_limit and
>> join_collapse_limit values both set to 100, run an EXPLAIN (no
>> ANALYZE) on your big problem query.  Let us know how long the
>> EXPLAIN runs.  If it gets any errors, copy and paste all available
>> information.  (General descriptions aren't likely to get us very
>> far.)  Since EXPLAIN without ANALYZE only *plans* the query, but
>> doesn't run it, it should not take long to do this.
>
> One issue here is that with the collapse limits cranked up to more
> than geqo_threshold, he's going to be coping with GEQO's partially-
> random plan selection; so whatever he reports might or might not be
> especially reflective of day-to-day results.  I'm tempted to ask
> that he also push up geqo_threshold.

In an earlier post[1] he said that he had geqo turned off.  It does
pay to be explicit, though; I'd hate to assume it's of if he's been
changing things.

Alberto, please ensure that you still have geqo off when you run the
test I suggested.  Also, I see that I didn't explicitly say that you
should send the ANALYZE output, but that's what would be helpful.

> It's possible that that *will* send the planning time to the moon;
> but it would certainly be worth trying, to find out what plan is
> produced.

Agreed.  What plan is produced, and how long that takes.  (And whether
he gets an out of memory error.)  I figured it was best to get a clear
answer to those before moving on....

-Kevin

[1]
http://archives.postgresql.org/pgsql-performance/2009-06/msg00186.php


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