Horton

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

Thomas Munro <thomas.munro@enterprisedb.com>

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From: Thomas Munro <thomas.munro@enterprisedb.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Peter Geoghegan <pg@bowt.ie>, Heikki Linnakangas <hlinnaka@iki.fi>, Pg Hackers <pgsql-hackers@postgresql.org>, Corey Huinker <corey.huinker@gmail.com>
Date: 2017-03-21T21:49:28Z
Lists: pgsql-hackers 
On Wed, Mar 22, 2017 at 10:03 AM, Robert Haas <robertmhaas@gmail.com> wrote:
> On Tue, Mar 21, 2017 at 3:50 PM, Peter Geoghegan <pg@bowt.ie> wrote:
>> I disagree with that. It is a
>> trade-off, I suppose. I have now run out of time to work through it
>> with you or Thomas, though.
>
> Bummer.

I'm going to experiment with refactoring the v10 parallel CREATE INDEX
patch to use the SharedBufFileSet interface from
hj-shared-buf-file-v8.patch today and see what problems I run into.

-- 
Thomas Munro
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