ORA-00054: resource is busy, but specified to obtain resource by NOWAIT, or timeout expired

The solution is as follows:

1. select session_id from v$locked_object; query the session ID locked by Oracle

2. SELECT sid, serial#, username, osuser FROM v$session where sid = 1; query the current session number information


SID SERIAL# USERNAME OSUSER
---------- ---------- ---------------------------- -- ------------------------------
       252 strong Username Operator
3, ALTER SYSTEM KILL SESSION '1,2000'; Kill the current session

Note : '252,strong' is: SID and SERIAL fields are concatenated