Horton

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

Peter Geoghegan <pg@bowt.ie>

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From: Peter Geoghegan <pg@bowt.ie>
To: Thomas Munro <thomas.munro@enterprisedb.com>
Cc: Robert Haas <robertmhaas@gmail.com>, Heikki Linnakangas <hlinnaka@iki.fi>, Pg Hackers <pgsql-hackers@postgresql.org>, Corey Huinker <corey.huinker@gmail.com>
Date: 2017-03-22T00:44:35Z
Lists: pgsql-hackers 
On Tue, Mar 21, 2017 at 2:49 PM, Thomas Munro
<thomas.munro@enterprisedb.com> wrote:
> 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.

I would be happy if you took over parallel CREATE INDEX completely. It
makes a certain amount of sense, and not just because I am no longer
able to work on it.

You're the one doing things with shared BufFiles that are of
significant complexity. Certainly more complicated than what parallel
CREATE INDEX needs in every way, and necessarily so. I will still have
some more feedback on your shared BufFile design, though, while it's
fresh in my mind.

-- 
Peter Geoghegan

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