Re: [Fwd: Re: Functionscan estimates] - Mailing list pgsql-performance

From Alvaro Herrera
Subject Re: [Fwd: Re: Functionscan estimates]
Date
Msg-id 20050414185809.GD28198@dcc.uchile.cl
Whole thread Raw
In response to Re: [Fwd: Re: Functionscan estimates]  (elein@varlena.com (elein))
Responses Re: [Fwd: Re: Functionscan estimates]
List pgsql-performance
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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