Phil, Michael, I appreciate your polite comments.
I understand as follows.
We can find it if we shorten the sampling interval, but a lot of information comes out.
# The balance is important.
Also, it is not good unless we have enough samples.
And I have to do various other things.
Is my understand correct?
It seems to me that it is difficult for me if my understanding is right.
Is DBA really able to solve bottlenecks with sampling?
# Since I am a beginner, I feel that way. And other people may not feel it difficult.
What I would like to say is that if we have information on the number of wait events and the wait time(like other DB), we can investigate more easily.
Of course, I understand that it also affects performance. So, I suggest a way that it can switch on and off, defaults is off.
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Naoki, Yotsunaga.