ORA-00054: Oracle queries locked objects and Solutions

Generally reported ORA-00054, it is likely that the object is locked, this error is generally "the resource is busy, but the specified way to obtain resources in NOWAIT, or timeout failure ", the solution is as follows:
 
1. query which objects are locked
 
Select object_name, machine, s. sid, s. serial #
From v $ locked_object l,
Dba_objects o,
V $ session s
Where l. object_id = o. object_id and l. session_id = s. sid;

2. Killing Processes
 
Alter system kill session 'sid, serial #';

In this way, the Lock Object problem is solved, but sometimes the ORA 00031 error "session marked for kill" may occur"
 
This indicates that the locked object has not been released for a long time and the process needs to be killed by the OS.
 
1. Find the process ID of the Lock Object
 
Select spid, oSUSEr, s. program
From v $ session s, v $ process p
Where s. paddr = p. addr and s. sid = sid (the sid here is the one found above)

2. Find the process and kill-9 to kill it.