Andres Freund <[email protected]> writes:
> On October 31, 2019 7:06:13 AM PDT, Andrzej Barszcz <[email protected]> wrote:
>> I almost finished patch optimizing non volatile function calls.
>>
>> select f(t.n) from t where f(t.n) > 10 and f(t.n) < 100; needs 3 calls
>> of
>> f() for each tuple,
>> after applying patch only 1.
>>
>> Any pros and cons ?
> Depends on the actual way of implementing this proposal. Think we need more
> details than what you idea here.
We've typically supposed that the cost of searching for duplicate
subexpressions would outweigh the benefits of sometimes finding them.
regards, tom lane
