Decrease of parallel query degree after upgrade from 11.2.0.3 to 12.1.0.2
Hi ,
After upgrade ( in-place) from 11.2.0.3 to 12.1.0.2 on AIX (7.1) , oracle 12c parallelize (auto dop) less then 11g ! why ?
in 11g AUTO DOP is between 1 and 30 , in 12c it is between 1 and 4 for almost all queries.
What's brakes parallelism in 12c ?
NB :
- system + dictionary + fixed tables statistics have been gathered after upgarde.
- IO calibration has been performed after upgarde.
Best regards.
GD.