I have a question about user ids in Snowplow. We have some doubts if the way we are using them is correct or not.
For every mobile event, the value of “userId” from client_session context is sent by the client as soon as we have a user id. But other properties of this context come from Snowplow (for ex. sessionID, sessionIndex, etc.). There is also another field in atomic events called “user_id”. We are not setting a value for this field but still get the values for all the events. From what I understood looking at this, “user_id” in atomic events is the custom user id to identify the user. But we are setting “userId” in client_session context for the same purpose. So my first question is: Is it the correct way to define custom user id or should we set it using the “user_id” field in the atomic events table? And my second question is, now that we are not setting this field “user_id” on the client side, what is the value we are receiving for this field? Does the value come from Snowplow?
It’s also confusing that the field in client_session context schema is called “userId” but in this blogpost under section " Out of the box identifiers on mobile", it’s called “user_id”. Which one is correct?