Horton

Re: [PATCH] Incremental sort

Tomas Vondra <tomas.vondra@2ndquadrant.com>

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From: Tomas Vondra <tomas.vondra@2ndquadrant.com>
To: David Steele <david@pgmasters.net>
Cc: James Coleman <jtc331@gmail.com>, 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: 2020-03-03T18:43:25Z
Lists: pgsql-hackers 
On Tue, Mar 03, 2020 at 12:17:22PM -0500, David Steele wrote:
>James and Tomas,
>
>On 1/21/20 10:03 AM, James Coleman wrote:
>>On Tue, Jan 21, 2020 at 9:58 AM Tomas Vondra
>><tomas.vondra@2ndquadrant.com> wrote:
>>>
>>>On Tue, Jan 21, 2020 at 09:37:01AM -0500, James Coleman wrote:
>>>>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.
>>>>
>>>
>>>Sure, sorry if that was not clear from my message - you're of course
>>>more than welcome to continue working on this. My understanding is that
>>>won't happen by the end of this CF, hence the move to 2020-03.
>>
>>Oh, yeah, I probably didn't word that reply well -- I just wanted to
>>add some additional detail to what you had already said.
>>
>>Thanks for your work on this!
>
>It doesn't look there has been much movement on this patch for the 
>last few CFs.  Are one or both of you planning to work on this for 
>v13? Or should we mark it for v14 and/or move it to the next CF.
>

I'm currently working on it, I plan to submit a new patch version
shortly - hopefully by the end of this week.


regards

-- 
Tomas Vondra                  http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

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.