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Re: ASSM in 10g RAC doesnt seem work that well

From: Martic Zoran <zoran_martic_at_yahoo.com>
Date: Tue, 29 Mar 2005 10:02:23 -0800 (PST)
Message-ID: <20050329180223.25124.qmail@web52605.mail.yahoo.com>


Christo,

I could not reproduce the same CPU time for ASM and non-ASM tablespaces in all mine environments. I have only Solaris/HP-UX environments and so cannot test Linux.

It could be OS specific of course. This is why I mentioned many times my environment and what I tested.

I am not using any specific parameter.
Maybe tuned a little bit interconnection between nodes in the past and that is all.

In your case you need to tune waits because that is what is the different in your case.
Nothing to do with the CPU usage because it is the same.
I assume your test is far from the real scenario?

Maybe you just proved when pushing with very high speed DML from both nodes then the collisions on blocks are more frequent and so pushing RAC to the end where performances starting to drop because of global cache.
This is very natural. As faster you push both sides of RAC you are going to pay the price.
In this particular case old non-ASSM with two freelists gave you better results.

I assume your HW/SW/interconnect environment may cause these things. You should be aware about the RAC tuning and global cache issues with bad interconnection.

Regards,
Zoran

> So right now we're basically lost?
>
> - We dont know why ASSM is using less CPU in
> Martic's case and not in mine
> - We dont know why ASSM is not working as expected
> in my RAC test
> case, and not in his.
>
> Any ideas ?
>
> Martic, why dont you post all your non-default
> parameters ? Could it
> be something OS specific, i did not see any LINUX
> results or I missed
> it ?
>
>
                



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Received on Tue Mar 29 2005 - 13:06:05 CST

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