dbms_stats.gather_table_stats(....degree=>6....,cascade=>true)

Hi all,

Today I was given with a question, why a dbms_stats with degree=>6 created 12 parallel process instead of 6 process.

I was wondering, how come Oracle create 12 process where as degree is only 6 process.  I think many of you might know already.

Oracle creates 6 parallel process as requested, but because of "cascade=>true", it spawns another 6 process to collect statistics from Index.

Oracle uses the following hint to run the stats collect process.

/*+ PARALLEL(t, 6) PARALLEL_INDEX(t,6) */