What is the probability of hitting a lock if you have 5-7 requests per second?

Question

MongoDB

MongoDB 3.0X
If I have 5-7 mixed requests per second to the database from PHP.

1. Some of the requests from them affect the same documents and some do not.
   
2. What is the probability of blocking in this case?
   
3. Will the process go smoothly and will all requests be executed in turn if they affect the same document or will an error occur?
   

Answer 1

lurkmore.to/Immolate_Improved!

Answer 2

With a sufficiently long use, the probability increases up to 100%, in 10 minutes of the test, there may not be any problem, but maybe there will be. But for a day of work, this probability increases significantly, but for a year?
So expect 100% collision and solve the problem based on that assumption.

Answer 3

I agree with Vyalkov, speaking within the terver, you need to determine the time interval, when this interval tends to infinity, the probability of almost any event is 1)
but does it matter for 5-7 requests, it will be unlocked and executed a little later, you don’t notice.