Horton

Re: POC: GROUP BY optimization

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: Dmitry Dolgov <9erthalion6@gmail.com>
Cc: Teodor Sigaev <teodor@sigaev.ru>, GavinFlower@archidevsys.co.nz, Michael Paquier <michael@paquier.xyz>, PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>, Tomas Vondra <tomas.vondra@2ndquadrant.com>
Date: 2019-01-31T11:24:07Z
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 2018-11-29 17:56:53 +0100, Dmitry Dolgov wrote:
> > On Tue, Oct 2, 2018 at 4:16 AM Michael Paquier <michael@paquier.xyz> wrote:
> >
> > On Sat, Jun 30, 2018 at 09:19:13AM +1200, Gavin Flower wrote:
> > > Additionally put an upper limit threshold on the number of combinations to
> > > check, fairly large by default?
> > >
> > > If first threshold is exceeded, could consider checking out a few more
> > > selected at random from paths not yet checked, to avoid any bias caused by
> > > stopping a systematic search.  This might prove important when N! is fairly
> > > large.
> >
> > Please note that the latest patch available does not apply, so this has
> > been moved to next CF 2018-11, waiting for input from its author.
> 
> Unfortunately, patch still has some conflicts, could you please rebase it?

As nothing has happened since, I'm marking this as returned with
feedback.

Greetings,

Andres Freund