Re: Effect of number of extents on Oracle I/O performance

What were the old extent sizes?

Alex

On Sat, Mar 14, 2009 at 10:23 AM, Nuno Souto <dbvision_at_iinet.net.au> wrote:

> Mark W. Farnham wrote,on my timestamp of 14/03/2009 10:58 AM:
>
> 2) When the extent size is very small (smaller than a multiblock read)
>> then
>> in cases where a multiblock read is interrupted by the extent boundary
>> every
>> time, then many small extents can be noticed. (If the extents are even a
>> reasonable size, then the collision interrupting a multiblock read quickly
>> becomes an infrequent event in a full table scan and the overhead
>> disappears
>> in the noise.
>>
>
> Seen this in some of the tablespaces in our DW. Unexplained slowdowns of
> FTS. Since then I've changed them to UNIFORM with size 50M or 100M,
> depending on the tables kept there. No more problems.
>
> --
> Cheers
> Nuno Souto
> in sunny Sydney, Australia
> dbvision_at_iinet.net.au
>
> --
> http://www.freelists.org/webpage/oracle-l
>
>
>

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