Re: [HACKERS] WIP: Aggregation push-down

Robert Haas <robertmhaas@gmail.com>

From: Robert Haas <robertmhaas@gmail.com>
To: Antonin Houska <ah@cybertec.at>
Cc: "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2018-01-29T14:43:49Z
Lists: pgsql-hackers
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


Commits

  1. Move estimate_hashagg_tablesize to selfuncs.c, and widen result to double.

  2. Remove unnecessairly duplicated gram.y productions