Re: Instability in select_parallel regression test

Amit Kapila <amit.kapila16@gmail.com>

From: Amit Kapila <amit.kapila16@gmail.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2017-02-27T02:37:41Z
Lists: pgsql-hackers
On Sun, Feb 26, 2017 at 11:15 PM, Robert Haas <robertmhaas@gmail.com> wrote:
> On Mon, Feb 20, 2017 at 7:52 AM, Amit Kapila <amit.kapila16@gmail.com> wrote:
>
>> The main point is if we
>> keep any loose end in this area, then there is a chance that the
>> regression test select_parallel can still fail, if not now, then in
>> future.  Another way could be that we can try to minimize the race
>> condition here and then adjust the select_parallel as suggested above
>> so that we don't see this failure.
>
> My guess is that if we apply the fix I suggested above, it'll be good
> enough.  If that turns out not to be true, then I guess we'll have to
> deal with that, but why not do the easy thing first?
>

Okay, that is also a sensible approach.  Your patch looks good to me,
though I have not tested it.

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


Commits

  1. Notify bgworker registrant after freeing worker slot.

  2. Replace min_parallel_relation_size with two new GUCs.

  3. Allow parallel workers to execute subplans.