Horton

Re: explain analyze output with parallel workers - question about meaning of information for explain.depesz.com

Robert Haas <robertmhaas@gmail.com>

View thread View on postgr.es
From: Robert Haas <robertmhaas@gmail.com>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: Hubert Lubaczewski <depesz@depesz.com>, pgsql-hackers mailing list <pgsql-hackers@postgresql.org>
Date: 2017-12-04T17:47:40Z
Lists: pgsql-hackers 
On Sat, Dec 2, 2017 at 8:04 AM, Amit Kapila <amit.kapila16@gmail.com> wrote:
> Attached patch contains regression test as well.  Note that I have
> carefully disabled all variable stats by using (analyze, timing off,
> summary off, costs off) and then selected parallel sequential scan on
> the right of join so that we have nloops and rows as variable stats
> and those should remain constant.

The regression test contains a whitespace error about which git diff
--check complains.

Also, looking at this again, shouldn't the reinitialization of the
instrumentation arrays happen in ExecParallelReinitialize rather than
ExecParallelFinish, so that we don't spend time doing it unless the
Gather is actually re-executed?

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

Commits

  1. Back-port fix for accumulation of parallel worker instrumentation.

  2. Test instrumentation of Hash nodes with parallel query.

  3. Try again to fix accumulation of parallel worker instrumentation.

  4. Revert "Fix accumulation of parallel worker instrumentation."

  5. Fix accumulation of parallel worker instrumentation.