By using System Tables (systen.billing.usage) I'm able to identity DBU usage per query, but I'm not able to identify who ran each query because is not part of the table. 

I'm also aware of query history where all the queries and who ran them is listed.

I was thinking if it might possible to combine both to get DBU usage per user, of if you know any other way to achieve same result.

I'll greatly appreciate it.