Horton

Re: POC: GROUP BY optimization

Jonathan S. Katz <jkatz@postgresql.org>

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From: "Jonathan S. Katz" <jkatz@postgresql.org>
To: Tomas Vondra <tomas.vondra@enterprisedb.com>, David Rowley <dgrowleyml@gmail.com>
Cc: Michael Paquier <michael@paquier.xyz>, Zhihong Yu <zyu@yugabyte.com>, "Andrey V. Lepikhov" <a.lepikhov@postgrespro.ru>, Teodor Sigaev <teodor@sigaev.ru>, Tomas Vondra <tomas.vondra@2ndquadrant.com>, PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>
Date: 2022-08-30T13:15:51Z
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

On 8/18/22 3:29 AM, Tomas Vondra wrote:
> 
> 
> On 8/18/22 03:32, David Rowley wrote:

>> Here are a couple of patches to demo the idea.
>>
> 
> Yeah, that's an option too. I should have mentioned it along with the
> cpu_operator_cost.
> 
> BTW would you mind taking a look at the costing? I think it's fine, but
> it would be good if someone not involved in the patch takes a look.

With RMT hat on, just a friendly reminder that this is still on the open 
items list[1] -- we have the Beta 4 release next week and it would be 
great if we can get this resolved prior to it.

Thanks!

Jonathan

[1] https://wiki.postgresql.org/wiki/PostgreSQL_15_Open_Items
[2] 
https://www.postgresql.org/message-id/9d251aec-cea2-bc1a-5ed8-46ef0bcf6c69@postgresql.org