Re: Slow CREATE INDEX PARALLEL
Date: Wed, 11 Mar 2009 15:28:29 -0700
What are the execution plans for each?
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 184.108.40.206
> 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 -- http://www.freelists.org/webpage/oracle-lReceived on Wed Mar 11 2009 - 17:28:29 CDT