CALL DBMS_STATS.GATHER_TABLE_STATS(
    'OWNER_NAME',
    'TABLE_NAME',
    ESTIMATE_PERCENT => 50,            -- longer but better than 1 for exec plans
    GRANULARITY => 'PARTITION',       -- or SUBPARTITION or nothing  
    PARTNAME => 'PARTITION_NAME',     -- or nothing
    DEGREE => 8                     -- parallelism
);