Horton

Re: [HACKERS] Parallel tuplesort (for parallel B-Tree index creation)

Amit Kapila <amit.kapila16@gmail.com>

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From: Amit Kapila <amit.kapila16@gmail.com>
To: Peter Geoghegan <pg@bowt.ie>
Cc: Robert Haas <robertmhaas@gmail.com>, Rushabh Lathia <rushabh.lathia@gmail.com>, Thomas Munro <thomas.munro@enterprisedb.com>, Heikki Linnakangas <hlinnaka@iki.fi>, Pg Hackers <pgsql-hackers@postgresql.org>, Corey Huinker <corey.huinker@gmail.com>
Date: 2018-01-13T13:34:09Z
Lists: pgsql-hackers 
On Sat, Jan 13, 2018 at 6:02 PM, Amit Kapila <amit.kapila16@gmail.com> wrote:
>
> The patch uses both parallel_leader_participation and
> force_parallel_mode, but it seems the definition is different from
> what we have in Gather.  Basically, even with force_parallel_mode, the
> leader is participating in parallel build. I see there is some
> discussion above about both these parameters and still, there is not
> complete agreement on the best way forward.  I think we should have
> parallel_leader_participation as that can help in testing if nothing
> else.
>

Or maybe just have force_parallel_mode.  I think one of these is
required to facilitate some form of testing of the parallel code
easily.  As you can see from my previous email, it was quite easy to
demonstrate a test with force_parallel_mode.

-- 
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com

Commits

  1. Support parallel btree index builds.

  2. Report an ERROR if a parallel worker fails to start properly.

  3. Transfer state pertaining to pending REINDEX operations to workers.

  4. Add a barrier primitive for synchronizing backends.

  5. Allow DML commands that create tables to use parallel query.

  6. Refactor GetOldestXmin() to use flags

  7. Fix regression in parallel planning against inheritance tables.

  8. Don't create "holes" in BufFiles, in the new logtape code.

  9. Simplify the code for logical tape read buffers.

  10. Fix excessive memory consumption in the new sort pre-reading code.

  11. Implement binary heap replace-top operation in a smarter way.

  12. Cosmetic code cleanup in commands/extension.c.

  13. Speed up planner's scanning for parallel-query hazards.

  14. Read from the same worker repeatedly until it returns no tuple.

  15. Improve tuplesort.c to support variable merge order. The original coding