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

Marko Tiikkaja <marko@joh.to>

From: Marko Tiikkaja <marko@joh.to>

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

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

Date: 2018-08-14T12:20:41Z

Lists: pgsql-bugs

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

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 Tue, Aug 14, 2018 at 2:50 PM, Amit Kapila <amit.kapila16@gmail.com>
wrote:

> This looks related, but I think this is a different issue.

Sure.

> The real
> reason for this case is that row_number is marked as parallel_safe
> which seems to be wrong.  I think it should be marked as
> parallel_unsafe.

Marking the function parallel safe doesn't seem wrong to me.  The
non-parallel-safe part is that the input gets fed to it in different order
in different workers.  And I don't really think that to be the function's
fault.

.m