Re: [Fwd: Re: Functionscan estimates]
От | elein@varlena.com (elein) |
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Тема | Re: [Fwd: Re: Functionscan estimates] |
Дата | |
Msg-id | 20050414205143.GB5278@varlena.com обсуждение исходный текст |
Ответ на | Re: [Fwd: Re: Functionscan estimates] (Alvaro Herrera <alvherre@dcc.uchile.cl>) |
Список | pgsql-performance |
Hmmm. My brain is being jostled and I'm confusing illustra-postgres, informix-postgres and postgresql. Some things had functions and some things had constants and I do not remember which products had what combination. But probably how they are in postgresql, post hellerstein, is how I am remembering. I can find out for sure, given a little time, by querying old contacts. It would be best if I had a clear question to ask, though. --elein On Thu, Apr 14, 2005 at 02:58:09PM -0400, Alvaro Herrera wrote: > On Thu, Apr 14, 2005 at 10:39:03AM -0700, elein wrote: > > > All functions could have a cost associated with them, set by the writer of > > the function in order for the planner to reorder function calls. > > The stonebraker airplane level example was: > > select ... from ... where f(id) = 3 and expensive_image_function(img) > > The idea, of course is to weight the expensive function so it was > > pushed to the end of the execution. > > So there was only a constant cost associated with the function? No > estimator function, for example? > > -- > Alvaro Herrera (<alvherre[@]dcc.uchile.cl>) > "If you have nothing to say, maybe you need just the right tool to help you > not say it." (New York Times, about Microsoft PowerPoint) >
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