Horton

Re: [PATCH] Push limit to sort through a subquery

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

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Douglas Doole <dougdoole@gmail.com>, Konstantin Knizhnik <k.knizhnik@postgrespro.ru>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2017-08-24T17:24:15Z
Lists: pgsql-hackers 
I wrote:
> To get the buildfarm back to green, I agree with the suggestion of
> setting force_parallel_mode=off for this test, at least for now.

Actually, there's an easier way: we can just make the test table be
TEMP.  That is a good idea anyway to prevent possible interference
from auto-analyze, which conceivably could come along at just the
wrong time and cause a plan change.

			regards, tom lane

Commits

  1. Propagate sort instrumentation from workers back to leader.

  2. Push tuple limits through Gather and Gather Merge.

  3. Code review for pushing LIMIT through subqueries.

  4. Make new regression test case parallel-safe, and improve its output.

  5. Push limit through subqueries to underlying sort, where possible.

  6. Move targetlist SRF handling from expression evaluation to new executor node.