Philosophy – Measurement
In my professional opinion, if your performance work is to have any credibility then you need to agree with and abide by this philosophy. I think it’s really what separates the real experts from the amateurs.
“Measurement is the first step that leads to control and eventually to improvement. If you can’t measure something, you can’t understand it. If you can’t understand it, you can’t control it. If you can’t control it, you can’t improve it.” – Dr. H. James Harrington
Discuss.
Black box. Can’t understand it. Can only poke at it with a stick. Fine for getting bananas, problematical for understanding the black box. For all we know, poking black box might make Jupiter break up into more black boxen.
Or For all we know, *not* poking black box might make Jupiter break up into more black boxen. More importantly, Why, are we messing with the Black Box. Then the cost of interaction can be rationalized and a value for it can be assessed or assigned.
But also remember that measurement impacts the state of the system. So don’t take this philosophy too much to the extent of impacting the system significantly.
What you’re mentioning is commonly associated with the Heisenberg Uncertainty Principle, however, often times metrics/counters are built in, so simply looking at them has zero cost. e.g. Oracle wait events.
I beg to disagree with the statement that “….often times metrics/counters are built in, so simply looking at them has zero cost.” as in Oracle observing some of those counters via v$ views does impact the state of the system albeit very nominally in most cases.
Other than that I agree with the original Philosophy behind this post!
I like the sentiment – but strongly urge a distrust of simple generalisations.