Session level parallelism setting to run scripts

alter session enable parallel ddl;
alter session force parallel ddl parallel 20;
alter session set db_file_multiblock_read_count = 256;
alter session set "_px_max_granules_per_slave"=3000;
alter session set "_px_index_sampling"=3000;
alter session set "_px_dynamic_sample_size"=3000;
ALTER SESSION ENABLE RESUMABLE TIMEOUT 3600;
alter session set parallel_force_local=TRUE;