Is a GUID unique 100% of the time?

Question

Is a GUID unique 100% of the time?

Will it stay unique over multiple threads?

Answer 1

Is a GUID unique 100% of the time?

Not guaranteed, since there are several ways of generating one. However, you can try to calculate the chance of creating two GUIDs that are identical and you get the idea: a GUID has 128 bits, hence, there are 2¹²⁸ distinct GUIDs – much more than there are stars in the known universe. Read the wikipedia article for more details.