Re: 'cost' and 'rows' for volitile function

Rob Sargent wrote:
> Richard Huxton wrote:
>> Rob Sargent wrote:
>>> pg-admin is showing 'COST 100' and 'ROWS 1000' for my explicitly
>>> VOLATILE functions.

> Thanks for the pointer back to CREATE FUNCTION docs. That would have
> told me that those value are indeed the defaults. I guess I'm somewhat
> surprised that they are in fact defautled. "COST" is too arbitrary for
> me to comment on, but my functions' results sets fall on both sides of
> 1000 rows, so I'm not sure giving this value to the planner does a lot
> of good. Luckily, my functions are typically pretty much stand-alone
> calls, and not part of some larger query.

If your functions are all called at the top-level then indeed it doesn't
matter. At a low level though, telling the planner function F1 costs
1000 times more than F2 is useful.

--
Richard Huxton
Archonet Ltd