Horton

Re: Eager aggregation, take 3

Richard Guo <guofenglinux@gmail.com>

View thread View on postgr.es
From: Richard Guo <guofenglinux@gmail.com>
To: David Rowley <dgrowleyml@gmail.com>
Cc: Robert Haas <robertmhaas@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>, Tender Wang <tndrwang@gmail.com>, Paul George <p.a.george19@gmail.com>, Andy Fan <zhihuifan1213@163.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>, pgsql-hackers@lists.postgresql.org, Matheus Alcantara <matheusssilv97@gmail.com>
Date: 2025-10-09T01:49:48Z
Lists: pgsql-hackers 
On Wed, Oct 8, 2025 at 8:14 PM David Rowley <dgrowleyml@gmail.com> wrote:
> +-- Enable eager aggregation, which by default is disabled.
> +SET enable_eager_aggregate TO on;

> The above comment and command mismatch to my understanding from
> looking at postgresql.conf.sample and guc_parameters.dat.

Right.  This GUC was disabled by default prior to v17, and this is a
leftover from that.  Will push a fix.  Thanks for pointing it out!

- Richard

Commits

  1. Fix eager aggregation for semi/antijoin inner rels

  2. Cover additional errors and corner conditions in repack.c

  3. Fix volatile function evaluation in eager aggregation

  4. Fix collation handling for grouping keys in eager aggregation

  5. Rename apply_at to apply_agg_at for clarity

  6. Fix comment in eager_aggregate.sql

  7. Remove unnecessary include of "utils/fmgroids.h"

  8. Implement Eager Aggregation

  9. Allow negative aggtransspace to indicate unbounded state size

  10. Add macros for looping through a List without a ListCell.

  11. Account for the effect of lossy pages when costing bitmap scans.

  12. Fix a thinko in join_is_legal: when we decide we can implement a semijoin