Sorry if I missed this already, but ... Say session A has already read the index and is doing some datafile access, when along comes session B with an index range scan. My understanding is that there's only one read/write head on the disk and contention results. Of course 10s or 100s of sessions would compound the issue. Is this reasoning flawed? Thanks, Jon Knight -----Original Message----- From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of David Sharples Sent: Monday, December 13, 2004 1:31 PM To: Oracle-L Freelists; thomas.mercadante@xxxxxxxxxxxxxxxxx Subject: Re: separate tablespaces for tables and indexes well a table and its index were never accessed at the same time anyway - always serially., always one then the other - so it doesnt matter if they were in the same tabespace / disk anyway. Back in the old todays, before SAN's and striping and all that placing hot segments on different disks was a good idea, but a process using a table and its index would never benefit from it So doing it for performance was / is a 'myth'. For management sure splitting them could be a good idea see http://asktom.oracle.com/pls/ask/f?p=4950:8:::::F4950_P8_DISPLAYID:901906930 328 for a good explanation Dave On Mon, 13 Dec 2004 14:19:56 -0500, Mercadante, Thomas F <thomas.mercadante@xxxxxxxxxxxxxxxxx> wrote: > David, > > Please describe your definition of "never". :) > > -----Original Message----- > From: David Sharples [mailto:davidsharples@xxxxxxxxx] > Sent: Monday, December 13, 2004 2:08 PM > To: oracle-l@xxxxxxxxxxxxx > Subject: Re: separate tablespaces for tables and indexes > > never was any need -- //www.freelists.org/webpage/oracle-l -- //www.freelists.org/webpage/oracle-l