Re: 64-Bit Oracle on Windows 2003

There are a number of reasons, but one of them is that certain data structures will grow in size. I did a presentation on this and looked at the latch structure. This one grew 25 percent in size (I think it was oracle9i). The simple reason for that is that sizeof(ptr_t *) has become twice as large. Now if that really impacts the overall performance I don't know, but moving to 64 bit from 32 bit and leaving the init.ora parameters the same, doesn't help performance. Infact you need to bump shared pool just to overcome the growth of the library cache structures. The number of buffers per hash chain in the library cache is also different from 32 bit to 64 bit, (due to size and hashing).

In my previous life I did some tests and saw this reduction, but that was in the period that Fred Flintstone was my taxi driver, so things may have changed ;-)

Anjo.

On 8/17/06, Kevin Closson <kevinc_at_polyserve.com> wrote:
>
>
>
> >> Hi Donald, I haven't been following this thread so please
> forgive me if I'm repeating something that's already been said, but you
> should be aware that migrating from 32-bit to 64-bit alone (all other
> variables remaining the same) can be expected to actually degrade
> performance slightly.
> ^^^^^^^^^^^^^^^^^^^^^^^^^
>
> ...can you tell us why? I have seen only extremely odd scenarios
> where this is true, and it generally isn't the Oracle Server.
>
>
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>

-- 
Anjo Kolk
Owner and Founder OraPerf Projects
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