Horton

Re: [HACKERS] WIP: Aggregation push-down

Antonin Houska <ah@cybertec.at>

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From: Antonin Houska <ah@cybertec.at>
To: Alvaro Herrera <alvherre@2ndquadrant.com>
Cc: Richard Guo <riguo@pivotal.io>, Tom Lane <tgl@sss.pgh.pa.us>, Michael Paquier <michael@paquier.xyz>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2019-09-05T06:10:58Z
Lists: pgsql-hackers 
Alvaro Herrera <alvherre@2ndquadrant.com> wrote:

> This stuff seems very useful.  How come it sits unreviewed for so long?

I think the review is hard for people who are not interested in the planner
very much. And as for further development, there are a few design decisions
that can hardly be resolved without Tom Lane's comments. Right now I recall
two problems: 1) is the way I currently store RelOptInfo for the grouped
relations correct?, 2) how should we handle types for which logical equality
does not imply physical (byte-wise) equality?

Fortunately it seems now that I'm not the only one who cares about 2), so this
problem might be resolved soon:

https://www.postgresql.org/message-id/CAH2-Wzn3Ee49Gmxb7V1VJ3-AC8fWn-Fr8pfWQebHe8rYRxt5OQ%40mail.gmail.com

But 1) still remains.

-- 
Antonin Houska
Web: https://www.cybertec-postgresql.com

Commits

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

  2. Remove unnecessairly duplicated gram.y productions