Re: ERROR: too many dynamic shared memory segments

On Tue, Nov 28, 2017 at 4:18 AM, Thomas Munro <thomas(dot)munro(at)enterprisedb(dot)com
> wrote:

> On Tue, Nov 28, 2017 at 10:05 AM, Jakub Glapa <jakub(dot)glapa(at)gmail(dot)com>
> wrote:
> > As for the crash. I dug up the initial log and it looks like a
> segmentation
> > fault...
> >
> > 2017-11-23 07:26:53 CET:192.168.10.83(35238):user(at)db:[30003]: ERROR:
> too
> > many dynamic shared memory segments
>
> I think there are two failure modes: one of your sessions showed the
> "too many ..." error (that's good, ran out of slots and said so and
> our error machinery worked as it should), and another crashed with a
> segfault, because it tried to use a NULL "area" pointer (bad). I
> think this is a degenerate case where we completely failed to launch
> parallel query, but we ran the parallel query plan anyway and this
> code thinks that the DSA is available. Oops.
>

I think BitmapHeapScan check whether dsa is valid or not if DSA is not
valid then it should assume it's non-parallel plan.

Attached patch should fix the issue.

--
Regards,
Dilip Kumar
EnterpriseDB: http://www.enterprisedb.com