Horton

Re: Eager aggregation, take 3

Andy Fan <zhihuifan1213@163.com>

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From: Andy Fan <zhihuifan1213@163.com>
To: Richard Guo <guofenglinux@gmail.com>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>, pgsql-hackers@lists.postgresql.org
Date: 2024-03-04T11:45:43Z
Lists: pgsql-hackers 
Richard Guo <guofenglinux@gmail.com> writes:

> Hi All,
>
> Eager aggregation is a query optimization technique that partially
> pushes a group-by past a join, and finalizes it once all the relations
> are joined.  Eager aggregation reduces the number of input rows to the
> join and thus may result in a better overall plan.  This technique is
> thoroughly described in the 'Eager Aggregation and Lazy Aggregation'
> paper [1].

This is a really helpful and not easy task, even I am not sure when I
can spend time to study this, I want to say "Thanks for working on
this!" first and hope we can really progress on this topic. Good luck! 

-- 
Best Regards
Andy Fan

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