Toad World® Forums

Parallel Hint in RAC Environment

How to get parallel to use multiple instances by using degree option. Let’s assume that I have a 2 node rac database.

Option 1 - If you don’t specify a degree it does it , but it creates 2 * cpu_count sessions * parallel_threads_per_cpu on each instance – which may be an overkill

Option 2 - If you use a degree it seems to just go to one instance only.

Option 3 – This should open up 8 sessions on both nodes both does not.

  1.  Select /*+ PARALLEL */ -
  2.  Select /*+ PARALLEL(4) */  -  Only goes to one session
  3.  Select /*+ PARALLEL(4,2) */  - Doesn’t seem to work the way I expected it