Re: [HACKERS] parallelize queries containing initplans - Mailing list pgsql-hackers

From Amit Kapila
Subject Re: [HACKERS] parallelize queries containing initplans
Date
Msg-id CAA4eK1KfqKrMjbsXpVmHT=FeQ=M8WmE6C1sV6b6aL3ZBie3gLQ@mail.gmail.com
Whole thread Raw
In response to Re: [HACKERS] parallelize queries containing initplans  (Robert Haas <robertmhaas@gmail.com>)
Responses Re: [HACKERS] parallelize queries containing initplans
List pgsql-hackers
On Thu, Oct 5, 2017 at 6:08 PM, Robert Haas <robertmhaas@gmail.com> wrote:
> On Thu, Oct 5, 2017 at 5:52 AM, Amit Kapila <amit.kapila16@gmail.com> wrote:
>> Now, unless, I am missing something here, it won't be possible to
>> detect params in such cases during forming of join rels and hence we
>> need the tests in generate_gather_paths.  Let me know if I am missing
>> something in this context or if you have any better ideas to make it
>> work?
>
> Hmm, in a case like this, I think we shouldn't need to detect it.  The
> Var is perfectly parallel-safe, the problem is that we can't use a
> not-safe plan for the inner rel.  I wonder why that's happening
> here...
>

It is because the inner rel (Result Path) contains a reference to a
param which appears to be at the same query level.  Basically due to
changes in max_parallel_hazard_walker().

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


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