Horton

Re: [PATCH] Incremental sort (was: PoC: Partial sort)

James Coleman <jtc331@gmail.com>

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From: James Coleman <jtc331@gmail.com>
To: Tomas Vondra <tomas.vondra@2ndquadrant.com>
Cc: Alvaro Herrera <alvherre@2ndquadrant.com>, Tom Lane <tgl@sss.pgh.pa.us>, Michael Paquier <michael@paquier.xyz>, Rafia Sabih <rafia.pghackers@gmail.com>, Peter Geoghegan <pg@bowt.ie>, Simon Riggs <simon@2ndquadrant.com>, Shaun Thomas <shaun.thomas@2ndquadrant.com>, Dmitry Dolgov <9erthalion6@gmail.com>, Alexander Korotkov <a.korotkov@postgrespro.ru>, PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>, Andreas Karlsson <andreas@proxel.se>
Date: 2020-04-06T21:27:44Z
Lists: pgsql-hackers

Attachments

On Mon, Apr 6, 2020 at 5:22 PM James Coleman <jtc331@gmail.com> wrote:
>
> On Mon, Apr 6, 2020 at 5:20 PM James Coleman <jtc331@gmail.com> wrote:
> >
> > On Mon, Apr 6, 2020 at 5:12 PM Tomas Vondra
> > <tomas.vondra@2ndquadrant.com> wrote:
> > >
> > > On Mon, Apr 06, 2020 at 04:54:38PM -0400, Alvaro Herrera wrote:
> > > >On 2020-Apr-06, Tom Lane wrote:
> > > >
> > > >> Locally, things pass without force_parallel_mode, but turning it on
> > > >> produces failures that look similar to rhinoceros's (didn't examine
> > > >> other BF members).
> > > >
> > > >FWIW I looked at the eight failures there were about fifteen minutes ago
> > > >and they were all identical.  I can confirm that, in my laptop, the
> > > >tests work without that GUC, and fail in exactly that way with it.
> > > >
> > >
> > > Yes, there's a thinko in show_incremental_sort_info() and it returns too
> > > soon. I'll push a fix in a minute.
> >
> > I'm stepping through this in a debugger; is what you're considering
> > that the for loop through the workers is off by one?
>
> Oh, nevermind, misread that.
>
> Looks like if the leader doesn't participate, then we don't show
> details for workers.
>
> Tomas: Do you already have a patch? If not, I can work one up.

Well, already have it, so I'll send it just in case.

James

Commits

  1. Further adjustments to Hashagg EXPLAIN ANALYZE output

  2. Rework EXPLAIN format for incremental sort

  3. Fix typos and improve incremental sort comments

  4. Stabilize incremental_sort tests

  5. Minor improvements in Incremental Sort explain

  6. Consider Incremental Sort paths at additional places

  7. Fix representation of SORT_TYPE_STILL_IN_PROGRESS.

  8. Fix failures in incremental_sort due to number of workers

  9. Fix show_incremental_sort_info with force_parallel_mode

  10. Implement Incremental Sort

  11. Fix handling of "Subplans Removed" field in EXPLAIN output.

  12. Fix EXPLAIN (SETTINGS) to follow policy about when to print empty fields.

  13. Ensure plpgsql result tuples have the right composite type marking.

  14. Propagate sort instrumentation from workers back to leader.

  15. Make new regression test case parallel-safe, and improve its output.

  16. Push limit through subqueries to underlying sort, where possible.

  17. Fix inappropriate printing of never-measured times in EXPLAIN.

  18. Fix some infelicities in EXPLAIN output for parallel query plans.