when we running table stats with degree=16, running in single session.
exec DBMS_STATS.GATHER_TABLE_STATS (ownname => 'CVSTAGING',tabname => 'TST_CSS_CONS_CREDIT_FACILITY',estimate_percent=> dbms_stats.auto_sample_size,cascade => true,method_opt => 'FOR ALL COLUMNS SIZE AUTO',degree=>16);
we have three databases (a,b & c), all the nodes are running in VM, RHEL 7.8
a - pproddb --> 4 node RAC
b - pstgdb --> 4 node RAC
c - stgtest -->2 node RAC
In DB a all the tables are working in parallel session,
in DB b only non-partitioned table parallel session in gather_table_stats working,
In DB c no tables are working in parallel session.
please note: we recently upgraded DB from 11.2.0.4 to 19c, physical machine to virtual.
kindly do the needful to rectify the issue.