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Re: [HACKERS] [PATCH] Incremental sort

Alexander Korotkov <a.korotkov@postgrespro.ru>

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From: Alexander Korotkov <a.korotkov@postgrespro.ru>
To: Teodor Sigaev <teodor@sigaev.ru>
Cc: Alexander Kuzmenkov <a.kuzmenkov@postgrespro.ru>, Tomas Vondra <tomas.vondra@2ndquadrant.com>, Andres Freund <andres@anarazel.de>, Darafei Komяpa Praliaskouski <me@komzpa.net>, Antonin Houska <ah@cybertec.at>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2018-04-07T16:23:21Z
Lists: pgsql-hackers

Attachments

On Sat, Apr 7, 2018 at 5:37 PM, Teodor Sigaev <teodor@sigaev.ru> wrote:

> by this patch.  Revised version is attached.
>>
>
> Fine, patch got several rounds of review in all its parts. Is any places
> which should be improved before commit?


Also I found that after planner changes of Alexander Kuzmenkov, incremental
sort
was used in cheapest_input_path() only if its child is cheapest total path.
That makes incremental sort to not get used almost never.
I've changed that to consider incremental sort path when we have some
presorted columns.  I also have to put changes in postgres_fdw regression
tests back, because incremental sort was used right there.

This revision of the patch also includes commit message.

------
Alexander Korotkov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company

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.