Re: [sqlsmith] Failed assertions on parallel worker shutdown

On Mon, May 23, 2016 at 2:19 PM, Andreas Seltenreich <seltenreich(at)gmx(dot)de>
wrote:
>
> I wrote:
> >> There's another class of parallel worker core dumps when testing master
> >> with sqlsmith. In these cases, the following assertion fails for all
> >> workers simulataneously:
> >>
> >> TRAP: FailedAssertion("!(mqh->mqh_partial_bytes <= nbytes)", File:
"shm_mq.c", Line: 386)
> >
> > I no longer observe these after applying these two patches by Amit
> > Kapila
>
> I spoke too soon: These still occur with the patches applied, but with
> much lower probability. (one core dump per 20e6 random queries instead
> of 1e6).
>
> Most of the collected plans look inconspicuous to me now, except for one
> that again had a subplan below a gather node (plan6).
>

This problem looks different from the previous problems you have reported.
Earlier problems were due to the reason that some unsafe/restricted
expressions were pushed below Gather node as part of target list whereas in
the plan6, it seems some unsafe node is pushed below Gather node. It will
be helpful if you can share the offending query?

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