Re: Defer selection of asynchronous subplans until the executor initialization stage

On Sat, Apr 9, 2022 at 1:58 AM Etsuro Fujita <etsuro.fujita@gmail.com> wrote:
> On Fri, Apr 8, 2022 at 9:43 PM Justin Pryzby <pryzby@telsasoft.com> wrote:
> > This patch seems to be causing the planner to crash.
> > Here's a query reduced from sqlsmith.
> >
> > | explain SELECT 1 FROM information_schema.constraint_column_usage WHERE 1 <= pg_trigger_depth();
> >
> > Program terminated with signal SIGSEGV, Segmentation fault.
>
> Reproduced.  Will look into this.

I think the cause of this is that mark_async_capable_plan() failed to
take into account that when the given path is a SubqueryScanPath or
ForeignPath, the given corresponding plan might include a gating
Result node that evaluates pseudoconstant quals.  My oversight.  :-(
Attached is a patch for fixing that.  I think v14 has the same issue,
so I think we need backpatching.

Best regards,
Etsuro Fujita