We use a number of third-party and in-house LTI tools to provide specialized functionality within Canvas. Some of these tools collect analytic data that we'd like to correlate to our Canvas (and other) data sets. Unfortunately, not all tools record the lis_person_sourcedid or custom_canvas_login_id which contain values that we could map back to our own systems.
It'd be a big help to us if one of the Canvas Data tables included the hash value that gets passed to an LTI provider in the user_id field. From a quick pass over the Canvas code, it looks like this is the value in the Canvas user table, column lti_context_id.