Oracle Ora-00054 Causes

-- ORA-00054 origin (resource busy and acquire with nowait)
SELECT l.SESSION_ID || ',' || v.SERIAL#     AS sid_serial,
       l.ORACLE_USERNAME                    AS ora_user,
       o.OBJECT_NAME,
       o.OBJECT_TYPE,
       DECODE(l.LOCKED_MODE,
              0, 'None',
              1, 'Null',
              2, 'Row-S (SS)',
              3, 'Row-X (SX)',
              4, 'Share',
              5, 'S/Row-X (SSX)',
              6, 'Exclusive',
              TO_CHAR(l.LOCKED_MODE)
           )                                AS lock_mode,
       o.STATUS,
       to_char(o.LAST_DDL_TIME, 'dd.mm.yy') AS last_ddl
FROM DBA_OBJECTS o, GV$LOCKED_OBJECT l, V$SESSION v
WHERE o.OBJECT_ID = l.OBJECT_ID
  AND l.SESSION_ID = v.SID
ORDER BY 2, 3;
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