Horton

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

Peter Geoghegan <pg@bowt.ie>

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From: Peter Geoghegan <pg@bowt.ie>
To: "Jonathan S. Katz" <jkatz@postgresql.org>
Cc: James Coleman <jtc331@gmail.com>, Justin Pryzby <pryzby@telsasoft.com>, Tomas Vondra <tomas.vondra@2ndquadrant.com>, Tom Lane <tgl@sss.pgh.pa.us>, Alvaro Herrera <alvherre@2ndquadrant.com>, Michael Paquier <michael@paquier.xyz>, Rafia Sabih <rafia.pghackers@gmail.com>, 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>, Peter Eisentraut <peter.eisentraut@2ndquadrant.com>, Andreas Karlsson <andreas@proxel.se>
Date: 2020-07-14T05:59:54Z
Lists: pgsql-hackers 
On Thu, Jul 9, 2020 at 12:06 PM Jonathan S. Katz <jkatz@postgresql.org> wrote:
> On 7/2/20 11:47 AM, James Coleman wrote:
> > It seems like the consensus over at another discussion on this topic
> > [1] is that we ought to go ahead and print the zeros [for machine
> > readable output formats], even though that creates some interesting
> > scenarios like the fact that disk sorts will print 0 for memory even
> > though that's not true.
> >
> > The change has already been made and pushed for hash disk spilling, so
> > I think we ought to use Justin's patch here.
>
> Do people agree with James analysis? From the RMT perspective, we would
> like to get this open item wrapped up for the next beta, given[1] is now
> resolved.

Tomas, Justin: Ping? Can we get an update on this?

Just for the record, David Rowley fixed the similar hashagg issue in
commit 40efbf8706cdd96e06bc4d1754272e46d9857875. I don't see any
reason for the delay here.

Thanks
-- 
Peter Geoghegan

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.