From: | elein(at)varlena(dot)com (elein) |
---|---|
To: | Alvaro Herrera <alvherre(at)dcc(dot)uchile(dot)cl> |
Cc: | Simon Riggs <simon(at)2ndquadrant(dot)com>, pgsql-performance(at)postgresql(dot)org, elein <elein(at)varlena(dot)com> |
Subject: | Re: [Fwd: Re: Functionscan estimates] |
Date: | 2005-04-14 20:51:43 |
Message-ID: | 20050414205143.GB5278@varlena.com |
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Thread: | |
Lists: | 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[(at)]dcc(dot)uchile(dot)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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