"Tom Lane" <[EMAIL PROTECTED]> writes:

> Gregory Stark <[EMAIL PROTECTED]> writes:
>> I imagine you've thought of this already but just in case, the cost of the
>> function call has to be combined with the selectivity to get this right. If
>> you can do an expensive but very selective clause first and save 100 cheap
>> calls that almost always return true it may still be worthwhile.
> I've thought of it, but I haven't figured out a reasonable algorithm for
> ordering the clauses in view of that.  Have you?

Hum, I hadn't tried. Now that I think about it it's certainly not obvious.

And picturing the possible failure modes I would rather it execute cheap
expressions more often than necessary than call some user-defined perl
function that could be doing i/o or involve waiting on other resources any
more than absolutely necessary. So I guess what you originally described is

  Gregory Stark
  EnterpriseDB          http://www.enterprisedb.com

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