True. The Temporary Segment has already been created. Next Extents are being allocated. That is why SEG$ is being updated. My question was about why the update to SEG$ has to re-update *EVERY* column in the table. No, it hasn't begun writing to the Index segment yet. I can differentiate between the TEMP segment for Sort operation in the Temporary Tablespace and the TEMP segment for the Index itself in the Index Tablespace. I know that with large indexes, it doesn't begin writing the Index segment immediately, only after the Sort operation TEMP segment has grown significantly. At 05:17 PM Tuesday, Niall Litchfield wrote: >On Tue, 01 Feb 2005 11:12:22 +0800, Hemant K Chitale ><hkchital@xxxxxxxxxxxxxx> wrote: > > > > While running a large CREATE INDEX using a Tablespace Temporary which is > > Dictionary Managed, ><snip sql> > > At this stage, it is still creating the Temporary Segment. Why does it > have > > to update ALL the columns of SEG$ > > for each Extent being allocated ? No wonder that DMS Temporary Tablespaces > > are called "slow". > >I don't believe that it is *creating* the temporary segment, I believe >that it is *allocating* extents for use during the sort. (it could of >course be allocating extents to the index itself - one would need to >see the values of the binds). > ><snip> >Niall Litchfield >Oracle DBA >http://www.niall.litchfield.dial.pipex.com Hemant K Chitale http://web.singnet.com.sg/~hkchital -- //www.freelists.org/webpage/oracle-l