Horton

Re: pgsql: Add parallel-aware hash joins.

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andres Freund <andres@anarazel.de>
Cc: Robert Haas <robertmhaas@gmail.com>, Thomas Munro <thomas.munro@enterprisedb.com>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2018-01-24T19:57:04Z
Lists: pgsql-hackers

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I wrote:
> I find that to be a completely bogus straw-man argument.  The point of
> looking at the prairiedog time series is just to see a data series in
> which the noise level is small enough to discern the signal.  If anyone's
> got years worth of data off a more modern machine, and they can extract
> a signal from that, by all means let's consider that data instead.

Just to make the point, I scraped the numbers for skink's "installcheck"
and "check" steps, which are data series I imagine at least Andres will
concede are worth paying attention to.  I made no attempt to clean
outliers, so these curves are pretty noisy, but I think there is a very
clear upward bump since mid-December.

			regards, tom lane

Commits

  1. Update obsolete sentence in README.parallel.

  2. Rewrite ConditionVariableBroadcast() to avoid live-lock.

  3. Tweak parallel hash join test case in hopes of improving stability.

  4. Rename pg_rewind's copy_file_range() to avoid conflict with new linux syscall.

  5. Fix some minor errors in new PHJ code.

  6. Fix EXPLAIN ANALYZE output for Parallel Hash.

  7. Fix rare assertion failure in parallel hash join.

  8. Cancel CV sleep during subtransaction abort.

  9. Add parallel-aware hash joins.

  10. Fix EXPLAIN ANALYZE of hash join when the leader doesn't participate.

  11. Add some regression tests that exercise hash join code.