Re: parallelize queries containing subplans

Dilip Kumar <dilipbalaut@gmail.com>

From: Dilip Kumar <dilipbalaut@gmail.com>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2017-01-12T06:41:39Z
Lists: pgsql-hackers
On Thu, Jan 12, 2017 at 9:22 AM, Amit Kapila <amit.kapila16@gmail.com> wrote:
> Valid point, but I think we can avoid that by returning false after
> foreach(..) loop.  I think one improvement could be that instead of
> manually checking the parallel safety of each subplan, we can
> recursively call max_parallel_hazard_walker for each subplan.

I agree that this way we can avoid the problem what I mentioned.
>
>
>> But, more than that it will be cleaner to not
>> handle AlternativeSubPlan here unless there is some strong reason?
>>
>
> Yeah, the reason is to avoid unnecessary recursion.  Also, in all
> other places in the code, we do handle both of them separately, refer
> cost_qual_eval_walker for somewhat similar usage.

ok.



-- 
Regards,
Dilip Kumar
EnterpriseDB: http://www.enterprisedb.com


Commits

  1. Allow parallel workers to execute subplans.