Re: [HACKERS] WIP: Aggregation push-down

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От Robert Haas
Тема Re: [HACKERS] WIP: Aggregation push-down
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Msg-id CA+TgmoYDDq332NZn-51fte_F_zUbyHNSgQjdHbEdHE5sU3=f9Q@mail.gmail.com
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Ответ на Re: [HACKERS] WIP: Aggregation push-down  (Antonin Houska <ah@cybertec.at>)
Ответы Re: [HACKERS] WIP: Aggregation push-down
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On Mon, Jan 29, 2018 at 3:32 AM, Antonin Houska <ah@cybertec.at> wrote:
> I think of a variant of this: implement an universal function that tests the
> binary values for equality (besides the actual arguments, caller would have to
> pass info like typlen, typalign, typbyval for each argument, and cache these
> for repeated calls) and set pg_proc(oprcode) to 0 wherever this function is
> sufficient. Thus the problematic cases like numeric, citext, etc. would be
> detected by their non-zero oprcode.

I don't think that's a good option, because we don't want int4eq to
have to go through a code path that has branches to support varlenas
and cstrings.  Andres is busy trying to speed up expression evaluation
by removing unnecessary code branches; adding new ones would be
undoing that valuable work.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company


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