ORA-00031

Title :

ORA-00031 session marked for kill

Cause :
The session specified in an ALTER SYSTEM KILL SESSION command cannot be killed immediately because the session is involved in a non-interruptible operation (for example, rolling back a transaction or being blocked by a network operation). The session has been marked to be killed as soon as possible after the current operation is done.

Action :
No action is required for the session to be killed, but further executions of the ALTER SYSTEM KILL SESSION command on this session may cause the session to be killed sooner.