How to use V$SESSION in Oracle to see distributed queries

Distributed queries are not like normal sessions. A user querying across a database link does not typically stay connected for a very long time. The connection only lasts as long as the query. So you'd have to catch the "connection" during the query run-time window. To see the session, you would have to query V$SESSION. This view does not show which sessions are using a database link. But you can query the MACHINE column of V$SESSION to see which users are currently querying from your other database servers.