Re: BUG #15324: Non-deterministic behaviour from parallelised sub-query

Amit Kapila <amit.kapila16@gmail.com>

From: Amit Kapila <amit.kapila16@gmail.com>

To: Andrew Fletcher <andy@prestigedigital.com>

Cc: Stephen Frost <sfrost@snowman.net>, Tom Lane <tgl@sss.pgh.pa.us>, Marko Tiikkaja <marko@joh.to>, Andres Freund <andres@anarazel.de>, PostgreSQL mailing lists <pgsql-bugs@lists.postgresql.org>

Date: 2018-08-16T06:59:26Z

Lists: pgsql-bugs

Commits

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Don't allow LIMIT/OFFSET clause within sub-selects to be pushed to workers.
- 568b4e1fdeb3 9.6.11 landed
- 1ceb103e7d1e 10.6 landed
- 830d7565902f 11.0 landed
- 75f9c4ca5a80 12.0 landed
Back-patch "Fix parallel hash join path search."
- 271b678436ce 9.6.11 landed
Prohibit pushing subqueries containing window function calculation to
- f658235a448a 9.6.11 landed
- bf61873ae3b6 10.6 landed
- 14e9b2a752ef 12.0 landed
- 2ce253cf57b1 11.0 landed
Fix parallel hash join path search.
- 655393a022bd 10.0 cited

On Thu, Aug 16, 2018 at 11:47 AM, Andrew Fletcher
<andy@prestigedigital.com> wrote:
>> (a) Consider the presence of a LIMIT/OFFSET in a sub-select as making
>> it parallel-unsafe.
>
>
> Presence of a LIMIT/OFFSET in a sub-select without an ORDER BY?
>

Yes, I wanted to do that, but Tom doesn't seem to like that especially
for back-branches.  Let me try to prepare a patch and then we can see
based on the complexity of fix.

-- 
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com