I have a database in which several processes are waiting for the “enq: DX – contention” event. After analyzing what they are doing observe that data are moving through a database link, in this case, this database is the client database link.
I connect to the server database link, where the select this pending “enq: DX – contention” is executed, there I see the processes parents who are waiting to “SQL * Net break / reset to dblink” event. Never change state.
Researching in MOS (Metalink) see there a note indicating that it may be a bug. Now this has been working fine for years and nothing has changed, neither the application, nor parameters of the database, and the data that are processed have experienced significant changes.
Finally I choose to kill the petition on the db server link. That solves the problem.
HTH – Antonio NAVARRO.