What is the cause and solution for Oracle error ORA-00031 session marked for kill?
Cause:
The session defined in an ALTER SYSTEM KILL SESSION command has been marked for kill even though it cannot be terminated right now (because it is rolling back or blocked on a network operation). This means it will be killed as soon as possible after its current uninterruptable operation is done.
Solution:
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.