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: 2017-01-16 15:43:15
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On Thu, Jan 12, 2017 at 7:56 PM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> 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.

After commit-ab1f0c8, this patch needs a rebase. Attached find
rebased version of the patch.

Thanks to Kuntal for informing me offlist that this patch needs rebase.

With Regards,
Amit Kapila.

Attachment Content-Type Size
pq_pushdown_subplan_v3.patch application/octet-stream 9.0 KB

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