今天在执行一个drop 表的操作时，报ORA-00054:resource busy and acquire with NOWAIT specified or timeout expired错误信息，
SQL> drop table user_test; drop table user_test * ERROR at line 1: ORA-00054: resource busy and acquire with NOWAIT specified or timeout expired [oracle@test ~]$ oerr ora 54 00054, 00000, "resource busy and acquire with NOWAIT specified or timeout expired" // *Cause: Interested resource is busy. // *Action: Retry if necessary or increase timeout.按照字面的意思是资源忙被占用了，所以第一时间想到看是哪个会话占用了资源，在做什么操作，数据库此时是不是有锁存在等。
SQL> select l.session_id,o.owner,o.object_name from v$locked_object l,dba_objects o where l.object_id=o.object_id; SESSION_ID OWNER OBJECT_NAME ---------- ------------ ------------------------ 1655 test user_test发现表user_test上有锁存在，根据session_id查找会话的详细信息：
SQL> SELECT sid, serial#, username, oSUSEr, terminal,program ,action, prev_exec_start FROM v$session where sid = 1655;通过查询v$session可以查到占用资源的会话详细信息，通过如下命令了可以杀掉占用资源的会话；之后再执行drop操作就没问题了。
SQL> alter system kill session '1655,43249'; System altered. SQL> drop table user_test; Table dropped.
