oracle error- ORA-00033: current session has empty migration password

ORA-00033: current session has empty migration password

Cause:     An attempt was made to detach or clone the current session and it has an empty 

migration password. This is not allowed.

Action:     Create the session with a non-empty migration password.

oracle error- ORA-00032: invalid session migration password

ORA-00032: invalid session migration password

Cause:     The session migration password specified in a session creation call was invalid (probably too long).

Action:     Retry with a valid password (less than 30 chars).

oracle error- ORA-00031: session marked for kill

ORA-00031:  session marked for kill

Cause:     The session specified in an ALTER SYSTEM KILL SESSION command cannot be killed 

immediately (because it is rolling back or blocked on a network operation), but it has  been marked for kill. This means it will be  killed as soon as possible after its current  uninterruptable 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.