[postgis-users] GIST index speed
mark.cave-ayland at siriusit.co.uk
Mon Jun 9 06:34:18 PDT 2008
Paul Ramsey wrote:
> 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.
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.
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