Horton

Re: Eager aggregation, take 3

Richard Guo <guofenglinux@gmail.com>

View thread View on postgr.es
From: Richard Guo <guofenglinux@gmail.com>
To: jian he <jian.universality@gmail.com>
Cc: 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, Robert Haas <robertmhaas@gmail.com>
Date: 2024-11-01T06:30:30Z
Lists: pgsql-hackers 
On Thu, Oct 31, 2024 at 9:16 PM jian he <jian.universality@gmail.com> wrote:
>
> hi.
> still trying to understand v13. found a bug.
>
> minimum test :
> drop table if exists t1, t2;
> CREATE TABLE t1 (a int, b int, c int);
> CREATE TABLE t2 (a int, b int, c int);
> SET enable_eager_aggregate TO on;
> explain(costs off, settings) SELECT avg(t2.a), t1.c FROM t1 JOIN t2 ON
> t1.b = t2.b GROUP BY t1.c having grouping(t1.c) > 0;
>
> havingQual can have GroupingFunc.
> if that happens, then segmentation fault.

Nice catch.  Thanks.

create_agg_clause_infos does check for GROUPING() expressions, but
not in the right place.  Will fix it in the next version.

Thanks
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