[postgis-users] GIST index speed

[Mark Cave-Ayland]

Paul Ramsey wrote:
> IMMUTABLE.
> 
> I bet when you have the function it's caching the result, and when you
> don't, it's re-fetching it. And because the bare result is a toasted
> tuple, the re-fetch is a lot more expensive.
> 
> P.

Hi Paul,

If only it were that simple ;)  I'd already tried removing the IMMUTABLE 
definition from SQL definition of mcatest() and it didn't make any 
difference to me - probably because adding a POSTGIS_DEBUG macro shows 
that it only gets called once in total rather than once per iteration of 
the nested loop scan.


ATB,

Mark.

-- 
Mark Cave-Ayland
Sirius Corporation - The Open Source Experts
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