2011/1/17 Tom Lane <tgl@sss.pgh.pa.us>:
> Pavel Stehule <pavel.stehule@gmail.com> writes:
>> it should to work without functional index - but not sure about effectivity
>
> As long as the function is VOLATILE, the planner can't use any
> intelligent query plan. Merge or hash join both require at least
> stable join keys.
sure, my first advice was a question about function volatility - and
my sentence was related to using immutable function.
regards
Pavel Stehule
>
> regards, tom lane
>