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Re: POC: GROUP BY optimization

Andrei Lepikhov <a.lepikhov@postgrespro.ru>

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From: Andrey Lepikhov <a.lepikhov@postgrespro.ru>
To: PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>
Cc: Teodor Sigaev <teodor@sigaev.ru>, Tomas Vondra <tomas.vondra@2ndquadrant.com>, Tom Lane <tgl@sss.pgh.pa.us>, David Rowley <dgrowleyml@gmail.com>, "a.rybakina" <a.rybakina@postgrespro.ru>, Белялов Дамир Наилевич <d.belyalov@postgrespro.ru>, Etsuro Fujita <etsuro.fujita@gmail.com>
Date: 2023-09-13T05:21:32Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Restore preprocess_groupclause()

  2. Rename PathKeyInfo to GroupByOrdering

  3. Add invariants check to get_useful_group_keys_orderings()

  4. Fix asymmetry in setting EquivalenceClass.ec_sortref

  5. Multiple revisions to the GROUP BY reordering tests

  6. Get rid of pg_class usage in SJE regression tests

  7. Rename index "abc" in aggregates.sql

  8. Explore alternative orderings of group-by pathkeys during optimization.

  9. Generalize the common code of adding sort before processing of grouping

  10. Fix out-dated comment in preprocess_groupclause()

  11. Force parallelism in partition_aggregate

  12. Optimize order of GROUP BY keys

Attachments

Hi,
Here is the patch rebased on the current master. Also, I fixed some 
minor slips and one static analyzer warning.
This is just for adding to the next commitfest and enforcing work with 
this patch.

One extra difference in newly added postgres_fdw tests is caused by this 
patch - see changes in the query plan in attachment.

-- 
regards,
Andrey Lepikhov
Postgres Professional