Re: parallelize queries containing subplans

From: Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>
To: Robert Haas <robertmhaas(at)gmail(dot)com>, Dilip Kumar <dilipbalaut(at)gmail(dot)com>
Cc: pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: parallelize queries containing subplans
Date: 2017-01-12 14:26:42
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On Thu, Jan 12, 2017 at 8:51 AM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> On Wed, Jan 11, 2017 at 9:58 PM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
>> The other alternative is to remember this information in SubPlan. We
>> can retrieve parallel_safe information from best_path and can use it
>> while generating SubPlan. The main reason for storing it in the plan
>> was to avoid explicitly passing parallel_safe information while
>> generating SubPlan as plan was already available at that time.
>> However, it seems there are only two places in code (refer
>> build_subplan) where this information needs to be propagated. Let me
>> know if you prefer to remember the parallel_safe information in
>> SubPlan instead of in Plan or if you have something else in mind?
> I think we should try doing it in the SubPlan, at least, and see if
> that comes out more elegant than what you have at the moment.

Okay, done that way. I have fixed the review comments raised by Dilip
as well and added the test case in attached patch.

With Regards,
Amit Kapila.

Attachment Content-Type Size
pq_pushdown_subplan_v2.patch application/octet-stream 9.0 KB

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