Eng 6012 inexists sp

I think that if the declaration and initialization of passedPredicate (which I'd rename hasMatchingTuple) was pulled out to before the while loop, this filter expression could be simplified as:

    if (m_isSemiScan && hasNullTuple && ! hasMatchingTuple) {

since hasNullTuple implies input_table->activeTupleCount() != 0
and passedPredicate/hasMatchingTuple implies output_temp_table->activeTupleCount() == 0