Re: separate data/inidex

I suspect this came about with Oracle 5
when disc was expensive, memory was
tiny, and every Oracle block access was a GET with no options for a PIN, so that logical I/O was converted to physical I/O at a much higher rate than it was with newer versions of Oracle and larger, modern machines.

Even then it was daft because it encouraged DBAs to put one table in tablespace X and its N indexes in tablespace Y - thus insuring that a single row inserted would require one block write on one disc, and N block writes on another.

--
Jonathan Lewis
http://www.jlcomp.demon.co.uk

Author of:
Practical Oracle 8i: Building Efficient Databases

Next Seminar - Australia - July/August
http://www.jlcomp.demon.co.uk/seminar.html

Host to The Co-Operative Oracle Users' FAQ
http://www.jlcomp.demon.co.uk/faq/ind_faq.html



Connor McDonald wrote in message <3CC2F8F8.7D93_at_yahoo.com>...


>

>Separating data and indexes is a very (very) special case of the

>argument for balancing IO.  I would suspect that it came about

>originally when everything when running rule based optimizer so your app

>was doing full scans or nested loops and that was it...Even then the

>advice was dubious in a multiuser database anyway...

>