Toad World® Forums

Parallel Hint in RAC Environment

Message from: Garivaldo

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


Historical Messages

Author: Garivaldo
Date: Fri Sep 30 10:51:12 PDT 2011

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

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