Re: Optimizing maximum/minimum queries (yet again)

From: Bruno Wolff III
Subject: Re: Optimizing maximum/minimum queries (yet again)
Date: ,
Msg-id: 20050409052752.GA9500@wolff.to
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In response to: Re: Optimizing maximum/minimum queries (yet again)  (Tom Lane)
Responses: Re: Optimizing maximum/minimum queries (yet again)  (Tom Lane)
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Optimizing maximum/minimum queries (yet again)  (Tom Lane, )
 Re: Optimizing maximum/minimum queries (yet again)  (Bruno Wolff III, )
  Re: Optimizing maximum/minimum queries (yet again)  (Tom Lane, )
   Re: Optimizing maximum/minimum queries (yet again)  (Bruno Wolff III, )
 Re: Optimizing maximum/minimum queries (yet again)  (Bruno Wolff III, )
  Re: Optimizing maximum/minimum queries (yet again)  (Tom Lane, )
 Re: Optimizing maximum/minimum queries (yet again)  (Bruno Wolff III, )
  Re: Optimizing maximum/minimum queries (yet again)  (Tom Lane, )
 Re: Optimizing maximum/minimum queries (yet again)  (Mark Kirkwood, )
 Re: Optimizing maximum/minimum queries (yet again)  (Neil Conway, )
  Re: Optimizing maximum/minimum queries (yet again)  (Tom Lane, )
   Re: Optimizing maximum/minimum queries (yet again)  (Neil Conway, )
    Re: Optimizing maximum/minimum queries (yet again)  (Tom Lane, )
     Re: Optimizing maximum/minimum queries (yet again)  (Bruno Wolff III, )
      Re: Optimizing maximum/minimum queries (yet again)  (Tom Lane, )

On Sat, Apr 09, 2005 at 00:57:11 -0400, Tom Lane <> wrote:
> 
> I don't have a problem with that, but I haven't quite convinced myself
> that we need to expend the cycles to check for it, either ...

You could have two different aggregates and end up with values
that could happen if the same set of rows was used to evaluate both.
I would expect that the sequential plan would be better for a volatile
where clause since you are going to execute it for every row anyway.
So disabling the optimization in that case isn't normally going to
slow things down.



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