Originally posted by slimdave
. . . . of all the statistics available I think that tuning the buffer cache hit ratio is the issue that has been unjustifiably force-fed down the throats of so many unwitting DBA's.
I've been thinking about this, and I wonder if it is a result of students wanting "instant gratification" or a "silver bullet" or a "black or white answer". Or the teachers/writers finding it easier to give the answer.

The logic might run:
1) If you could only get one statistic from your db, which would you choose? I guess I would choose the hit ratio.
2) So the hit ratio is the best.
3) We want nothing but the best.
4) We will only tune the hit ratio.

(Obviously you get the same kind of nonsense if you choose another statistic.)