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

Amit Kapila <amit.kapila16@gmail.com>

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

To: Stephen Frost <sfrost@snowman.net>

Cc: Tom Lane <tgl@sss.pgh.pa.us>, Marko Tiikkaja <marko@joh.to>, Andres Freund <andres@anarazel.de>, Andrew Fletcher <andy@prestigedigital.com>, PostgreSQL mailing lists <pgsql-bugs@lists.postgresql.org>

Date: 2018-08-20T10:52:25Z

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 Mon, Aug 20, 2018 at 4:20 PM, Amit Kapila <amit.kapila16@gmail.com> wrote:
> On Thu, Aug 16, 2018 at 9:25 AM, Amit Kapila <amit.kapila16@gmail.com> wrote:
>> On Wed, Aug 15, 2018 at 4:40 PM, Stephen Frost <sfrost@snowman.net> wrote:
>> (b) Consider the presence of any window function calculation as
>> parallel-restricted operation.
>>
>
> For this, we need to mark all the window functions like row_number,
> rank, dense_rank, etc as parallel-restricted.   Additionally, we also
> need to detect the presence of aggregate functions that act as window
> functions (when an OVER clause follows the call).   Attached patch
> treat_window_func_calc_parallel_restricted_v1 implements the fix.
>

As this patch changes the catalog contents, we need to bump catalog
version number.  However, I have left it for later once we get a
review and or testing of the patch.

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