Re: negative bitmapset member not allowed Error with partition pruning

Rajkumar Raghuwanshi <rajkumar.raghuwanshi@enterprisedb.com> writes:
> I am getting "ERROR:  negative bitmapset member not allowed" when
> enable_partition_pruning set to true with below test case.

Confirmed here.  It's failing in perform_pruning_combine_step,
which reaches this:

        result->bound_offsets = bms_add_range(NULL, 0, boundinfo->ndatums - 1);

with boundinfo->ndatums == 0.  It's not clear to me whether that situation
should be impossible or not.  If it is valid, perhaps all we need is
something like

        if (boundinfo->ndatums > 0)
            result->bound_offsets = bms_add_range(NULL, 0, boundinfo->ndatums - 1);
        else
            result->bound_offsets = NULL;

although that then opens the question of whether downstream code is
OK with bound_offsets being empty.

(BTW, I'm not sure that it was wise to design bms_add_range to fail for
empty ranges.  Maybe it'd be better to redefine it as a no-op for
upper < lower?)

            regards, tom lane