Horton

Re: Eager aggregation, take 3

Richard Guo <guofenglinux@gmail.com>

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From: Richard Guo <guofenglinux@gmail.com>
To: Robert Haas <robertmhaas@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
Date: 2024-12-21T01:05:09Z
Lists: pgsql-hackers

Attachments

On Tue, Dec 17, 2024 at 12:42 PM Richard Guo <guofenglinux@gmail.com> wrote:
> Attached is the patch rebased on the latest master.  It refines the
> theoretical justification for the correctness of this transformation
> in README and commit message.  It also adds the check for image
> equality for all grouping keys used in partial aggregation, and fixes
> the issue reported by Jian.  It does not yet handle the RLS case
> though.

I've looked at the RLS case.  AFAIU we want to prevent any
non-leakproof aggregation functions from being pushed down past
securityQuals.  I added a check in create_agg_clause_infos to ensure
that no aggregation is pushed down if securityQuals are present along
with any non-leakproof aggregate functions.  I know this might be
overly strict, but for now, I want to focus on the eager aggregation
transformation itself.  We can relax this restriction in subsequent
patches after this already large one.

Attached is the latest patch, which also includes some cosmetic
tweaks.  I am seeking the possibility of pushing this by the end of
January, so that I can have enough time to react to any bugs before
the feature freeze.

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