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: 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>, Tom Lane <tgl@sss.pgh.pa.us>, PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>, Alvaro Herrera <alvherre@2ndquadrant.com>
Date: 2020-01-21T14:37:01Z
Lists: pgsql-hackers 
On Tue, Jan 21, 2020 at 9:25 AM Tomas Vondra
<tomas.vondra@2ndquadrant.com> wrote:
>
> Hi,
>
> This patch has been marked as WoA since end of November, and there has
> been no discussion/reviews since then :-( Based on off-list discussion
> with James I don't think that's going to change in this CF, so I'll move
> it to the next CF.
>
> I plan to work on the planner part of this patch before 2020-03, with
> the hope it can still make it into 13.

In that off-list discussion I'd mentioned to Tomas that I would still
like to work on this, just my other responsibilities at work have left
me little time to work on the most important remaining part of this
(the planner parts) since that requires a fair amount of focus and
time.

That being said, the patch also needs some more work on improving
EXPLAIN ANALYZE output (perhaps min/max/mean or median of
memory usage number of groups in each sort mode), and I think it's far
more feasible that I can tackle that piecemeal before the next CF.

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.