Horton

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

Peter Geoghegan <pg@heroku.com>

View thread View on postgr.es
From: Peter Geoghegan <pg@heroku.com>
To: Pg Hackers <pgsql-hackers@postgresql.org>
Cc: Corey Huinker <corey.huinker@gmail.com>
Date: 2016-08-22T21:43:13Z
Lists: pgsql-hackers 
On Mon, Aug 1, 2016 at 3:18 PM, Peter Geoghegan <pg@heroku.com> wrote:
> Attached WIP patch series:

This has bitrot, since commit da1c9163 changed the interface for
checking parallel safety. I'll have to fix that, and will probably
take the opportunity to change how workers have maintenance_work_mem
apportioned while I'm at it. To recap, it would probably be better if
maintenance_work_mem remained a high watermark for the entire CREATE
INDEX, rather than applying as a per-worker allowance.


-- 
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