Horton

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

Peter Geoghegan <pg@bowt.ie>

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From: Peter Geoghegan <pg@bowt.ie>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Amit Kapila <amit.kapila16@gmail.com>, Thomas Munro <thomas.munro@enterprisedb.com>, Rushabh Lathia <rushabh.lathia@gmail.com>, Heikki Linnakangas <hlinnaka@iki.fi>, Pg Hackers <pgsql-hackers@postgresql.org>, Corey Huinker <corey.huinker@gmail.com>
Date: 2018-02-02T21:35:59Z
Lists: pgsql-hackers 
On Fri, Feb 2, 2018 at 10:38 AM, Peter Geoghegan <pg@bowt.ie> wrote:
> On Fri, Feb 2, 2018 at 10:37 AM, Robert Haas <robertmhaas@gmail.com> wrote:
>> If you could keep an eye on the buildfarm and investigate anything
>> that breaks, I would appreciate it.

> I can keep an eye on it throughout the day.

There is a benign Valgrind error that causes the lousyjack animal to
report failure. It looks like this:

==6850== Syscall param write(buf) points to uninitialised byte(s)
==6850==    at 0x4E4D534: write (in /usr/lib64/libpthread-2.26.so)
==6850==    by 0x82328F: FileWrite (fd.c:2017)
==6850==    by 0x8261AD: BufFileDumpBuffer (buffile.c:513)
==6850==    by 0x826569: BufFileFlush (buffile.c:657)
==6850==    by 0x8262FB: BufFileRead (buffile.c:561)
==6850==    by 0x9F6C79: ltsReadBlock (logtape.c:273)
==6850==    by 0x9F7ACF: LogicalTapeFreeze (logtape.c:906)
==6850==    by 0xA05B0D: worker_freeze_result_tape (tuplesort.c:4477)
==6850==    by 0xA05BC6: worker_nomergeruns (tuplesort.c:4499)
==6850==    by 0x9FCA1E: tuplesort_performsort (tuplesort.c:1823)

I'll need to go and write a Valgrind suppression for this. I'll get to
it later today.

-- 
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