ga_session_id is unique identifier on Google Analytics?

Question

I checked the official docs here: https://support.google.com/firebase/answer/7061705?hl=en

But, when I checked my data, there are several user_id and user_pseudo_id in one ga_session_id. How is it possible?

Answer 1

ga_session_id is not supposed to be globally unique (afaik it's based on a skewed in-device timestamp) but in most circumstances (except for edge cases) it should be locally unique for a given user_pseudo_id