Re: [sqlsmith] Failed assertion in parallel worker (ExecInitSubPlan) - Mailing list pgsql-hackers

From Amit Kapila
Subject Re: [sqlsmith] Failed assertion in parallel worker (ExecInitSubPlan)
Date
Msg-id CAA4eK1+cA33KJK2kPvVLeywJD3nyikpjJ1z-XZaDFhTPks4+Jw@mail.gmail.com
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In response to Re: [sqlsmith] Failed assertion in parallel worker (ExecInitSubPlan)  (Andreas Seltenreich <seltenreich@gmx.de>)
List pgsql-hackers
On Sun, May 22, 2016 at 9:32 PM, Andreas Seltenreich <seltenreich@gmx.de> wrote:
>
> Amit Kapila writes:
>
> > avoid_restricted_clause_below_gather_v1.patch
> > prohibit_parallel_clause_below_rel_v1.patch
>
> I didn't observe any parallel worker related coredumps since applying
> these.  The same amount of testing done before applying them yielded
> about a dozend.
>

Thanks for verification.

> Dilip Kumar writes:
>
> > So now its clear that because of sub query pullup, we may get expression in
> > targetlist while creating single table path list. So we need to avoid
> > parallel plan if it contains expression.
>
> This sounds like a rather heavy restriction though…
>

I think what Dilip means by above statement is to avoid parallel plan if target list contains parallel unsafe or restricted expressions.  We already restrict generation of parallel plans if qualification for a relation contains such expressions (refer set_rel_consider_parallel()), so this doesn't sound to be heavy restriction.



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

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