Horton

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

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: James Coleman <jtc331@gmail.com>
Cc: Alvaro Herrera <alvherre@2ndquadrant.com>, Tomas Vondra <tomas.vondra@2ndquadrant.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>, PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>, Andreas Karlsson <andreas@proxel.se>
Date: 2020-03-31T17:58:24Z
Lists: pgsql-hackers 
James Coleman <jtc331@gmail.com> writes:
> On Tue, Mar 31, 2020 at 1:04 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Perhaps the semantics are such that that's actually sensible, but it's
>> far from a straightforward remapping of the old enum.

> Right, I didn't see the explicit "= 0" in other enums there, so it
> made me wonder if it was intentional to designate that one had to be
> 0, but I guess without a comment that's a lot of inference.

It's possible that somebody meant that as an indicator that the code
depends on palloc0() leaving the field with that value.  But if so,
you'd soon find that out ... and an actual comment would be better,
anyway.

			regards, tom lane

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.