对数据进行逻辑备份时出错：

备份一直没有问题，服务器死机后重启服务器exp出现问题：
Connected to: Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Produc
tion
With the Partitioning, OLAP and Data Mining options
Export done in ZHS16GBK character set and AL16UTF16 NCHAR character set
. exporting pre-schema procedural objects and actions
. exporting foreign function library names for user JD
. exporting PUBLIC type synonyms
. exporting private type synonyms
. exporting object type definitions for user JD
About to export JD's objects ...
. exporting database links
. exporting sequence numbers
. exporting cluster definitions^[[B
EXP-00056: ORACLE error 4021 encountered
ORA-04021: timeout occurred while waiting to lock object
EXP-00000: Export terminated unsuccessfully

-------------------------------------------------------------------

Cause
There is a lock on a library object when doing the export.
Error: ORA 4021
Text: time-out occurred while waiting to lock object
-------------------------------------------------------------------------------
Cause: While trying to lock a library object, a time-out occurred.
Action: Retry the operation later.--等待一会再执行操作
Bug 3386590 4021: TIMEOUT OCCURRED WHILE WAITING TO LOCK OBJECT
Fixed In Ver: 10.2.
遇到LIBARY CACHE PIN  ，LIBARY CACHE LOCK了