On 09.05.2007 16:58, Valentin Minzatu wrote:
> On May 9, 10:37 am, Robert Klemme <shortcut..._at_googlemail.com> wrote:
>> On 09.05.2007 16:22, Valentin Minzatu wrote:
>>
>>
>>
>>
>>
>>> On May 9, 6:48 am, Robert Klemme <shortcut..._at_googlemail.com> wrote:
>>>> Hi,
>>>> this is on 10.2.0.1.0. I think I remember that there is a parameter
>>>> that will affect how Oracle costs IO but can't seem to find it (searched
>>>> DB Reference, Performance Tuning Guide, PL/SQL Package Reference, Web).
>>>> Does my memory fail me?
>>>> Do you know other ways to influence how Oracle costs single block reads
>>>> vs. multi block reads (apart from DB_FILE_MULTIBLOCK_READ_COUNT and
>>>> hinting that is)? Thank you!
>>>> Kind regards
>>>> robert
>>> What is the problem you try to address by chaging the optimizer
>>> behavior?
>> I'm trying to bias the CBO towards multi block reads.
>>
>> Kind regards
>>
>> robert- Hide quoted text -
>>
>> - Show quoted text -
>
> Why do you need to do that? (i.e. is this a DW system? )
Si. And experiments have shown that plans with MBR's perform
significantly better than those without. And I'd prefer to use DB
parameters or other means over hints.
Regards
robert
Received on Wed May 09 2007 - 10:51:16 CDT
