measuring the size of updates

In my Oracle7.3. Performance Tuning course, they mentioned that to = reduce
migration we should set PCTFREE properly.

They also provided the following formula:

PCTFREE =3D 100 * [ avg. size of updates / (avg. size of updates + = initial
row length) ]

It occurred to me that since Oracle didn't explain how we should go = about
doing this, maybe I should ask. Our instructor said I should use Pre = Update
and Post Update triggers to keep track of this, but he didn't go into detail.

Has anyone done this successfully?

What was the impact on performance?

I want to incorporate this calculation into my weekly PT script, if possible. =20

TIA
Patrice Boivin
Systems Analyst (Oracle Certified DBA)

Systems Admin & Operations | Admin. et Exploit. des syst=E8mes
Technology Services        | Services technologiques
Informatics Branch         | Direction de l'informatique=20
Maritimes Region, DFO      | R=E9gion des Maritimes, MPO

E-Mail: boivinp_at_mar.dfo-mpo.gc.ca <mailto:boivinp_at_mar.dfo-mpo.gc.ca>=20 Received on Mon Jul 10 2000 - 07:21:34 CDT