Horton

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

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Prabhat Sahu <prabhat.sahu@enterprisedb.com>, Peter Geoghegan <pg@bowt.ie>, Tomas Vondra <tomas.vondra@2ndquadrant.com>, 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>, Andres Freund <andres@anarazel.de>
Date: 2018-03-08T16:57:49Z
Lists: pgsql-hackers 
On Thu, Mar 8, 2018 at 11:45 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Prabhat Sahu <prabhat.sahu@enterprisedb.com> writes:
>> On Wed, Mar 7, 2018 at 7:51 PM, Robert Haas <robertmhaas@gmail.com> wrote:
>>> That looks like the background worker got killed by the OOM killer.  How
>>> much memory do you have in the machine where this occurred?
>
>> I have ran the testcase in my local machine with below configurations:
>> Environment: CentOS 7(64bit)
>> HD : 100GB
>> RAM: 4GB
>> Processor: 4
>
> If you only have 4GB of physical RAM, it hardly seems surprising that
> trying to use 8GB of maintenance_work_mem would draw the wrath of the
> OOM killer.

Yup.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

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