As I think someone else noted, Heisenberg's uncertainty principle related to the location of quantum particles at a specific point in time. Your participant was thinking of Schroedinger's cat. Anyway, his point is correct to a certain extent. You need to choose monitoring tools that will have minimal effect on the system being monitored. Oracle has a fairly extensive suite of tools for monitoring performance included in the software from about 8i on up, and they are pretty good about keeping the impact small. -----Original Message----- From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Ted Coyle Sent: Tuesday, July 31, 2007 2:40 PM To: 'oracle-l' Subject: Heisenberg and measurement intrusion.... I'm on an Oracle performance project and a project participant made a statement regarding measurement intrusion. Is the statement below accurate? "So the Heisenberg uncertainty principle mandates we run without monitoring as a baseline." I responded with a wikipedia link which I'll send later, but I'd like to get opinions first. :) Regards, Ted -- //www.freelists.org/webpage/oracle-l ------------------------------------------------------------------------------ NOTICE: This electronic mail message and any attached files are confidential. The information is exclusively for the use of the individual or entity intended as the recipient. If you are not the intended recipient, any use, copying, printing, reviewing, retention, disclosure, distribution or forwarding of the message or any attached file is not authorized and is strictly prohibited. If you have received this electronic mail message in error, please advise the sender by reply electronic mail immediately and permanently delete the original transmission, any attachments and any copies of this message from your computer system. Thank you. ============================================================================== -- //www.freelists.org/webpage/oracle-l