LP Bug: 1326103 - Optimizer always restricts HbaseScan DoP to number of nodes in cluster

The DoP is always restricted to number of Nodes for some plans. For example the plan produced by the optimizer for query
select * from shb1<<+ cardinality 10e6 >> is always:

>>explain options 'f' xx;

LC RC OP OPERATOR OPT DESCRIPTION CARD
---- ---- ---- -------------------- -------- -------------------- ---------

2 . 3 root 1.00E+000
1 . 2 esp_exchange 1:2(range) 1.00E+007
. . 1 trafodion_scan SHB1 1.00E+007

— SQL operation complete.

setting parallel_num_esps and/or max_esps_per_cpu_per_op to increase the DoP didn't work. The table has 75 partitions and a big table. The default plan produced by the optimizer with DoP 2 is not an optimal one.