Re: Slow CREATE INDEX PARALLEL

I would recommend a DOP that is a power of 2 (2/4/8/16/...), as it leads to the most even distribution of work (similar to why power of 2 is recommended for the number of hash partitions - it yields the best/even distribution of keys).

On Wed, Mar 11, 2009 at 2:18 PM, Keith Moore <kmoore_at_zephyrus.com> wrote:
> Oracle 9.2.0.4
> Solaris 8
>
> I have a database where creating an index on a particular table takes about 25
> minutes but if I create a similar index on the same table with the "PARALLEL
> 3" clause it takes over 100 minutes.
>
> I ran a 10046 trace on both statements and the normal CREATE INDEX does
> multiblock (scattered) reads, generally 1 Megabyte per read. The problem is
> that the index created PARALLEL 3 does single block (sequential) reads.
>
> Can anyone explain why it would do single block reads? Is this a bug?

-- 
Regards,
Greg Rahn
http://structureddata.org
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