Extracting data from oracle to starrocks using jdbc catalog

we are trying to run select command on oracle table from starrocks using jdbc catalog, but on checking sessions at oracle end, only 1 BE node is running select, not other 4 nodes. also i would like to run query in parallel.

i have tried setting set parallel_fragment_exec_instance_num = 8, but not change.

orcle session snapshot:

please help

@atwong