Oracle - number of CPUs changing on the fly

[Erik Trolle]

How will Oracle react to the number of CPUs changing on the fly? This feature will be part of virtual partitions in HP-UX.
With 1 CPU, Oracle will not spin on a lock. With >1 CPU Oracle will spin on a lock. So changing from 2 to 1 CPU may have performance impact. Otherwise I would expect no problems.
Has anyone actually tried it out?

[melvyn burnard]

Sounds to me like the sort of question you should actually bounce off of Oracl ethemselves.

[Andreas D. Skjervold]

Hi
You will get a performenc boost if your procesess today does a lot of waiting to aquire latches.
If this isn't the case (as it was in my case), adjusting the spin_count parameter had no effect.
Do not increase the spin_count parameter if your already high on CPU usage.

Another thing is the fact that your computer gets extra CPU cylces for all other task. And that might speed things up a bit.

Or else you can just run a seti@home client on it... (just kidding)

Andreas