Re: [PATCH] Negative Transition Aggregate Functions (WIP)
| От | David Rowley |
|---|---|
| Тема | Re: [PATCH] Negative Transition Aggregate Functions (WIP) |
| Дата | |
| Msg-id | CAApHDvr-m_79bdY_xhFd4WkPHdwd8tq4_vM42dwp7j4Ysa6SNA@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: [PATCH] Negative Transition Aggregate Functions (WIP) (David Rowley <dgrowleyml@gmail.com>) |
| Ответы |
Re: [PATCH] Negative Transition Aggregate Functions (WIP)
|
| Список | pgsql-hackers |
On Tue, Jan 14, 2014 at 9:09 PM, David Rowley <dgrowleyml@gmail.com> wrote:
I think unless anyone has some objections I'm going to remove the inverse transition for SUM(numeric) and modify the documents to tell the user how to build their own FAST_SUM(numeric) using the built in functions to do it. I'm starting to think that playing around with resetting numeric scale will turn a possible 9.4 patch into a 9.5/10.0 patch. I see no reason why what's there so far, minus sum(numeric), can't go in...
Of course its only now that I discover that this is not possible to do this:
CREATE AGGREGATE fast_sum (numeric)
(
stype = numeric,
sfunc = numeric_avg_accum,
invfunc = numeric_avg_accum_inv,
finalfunc = numeric_sum
);
because SUM(numeric) uses an internal type to store the transition state.
hmmm, built-in fast_sum anyone?
Is there any simple way to limit these to only be used in the context of a window? If so is it worth it?
Would we want fast_sum() for float too?
Regards
David Rowley
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