在告警日志中，可能遇到大量如下提示信息：
Fri Dec 27 08:51:40 2013
kewastUnPackStats(): bad magic 1 (0x0000000067C4BE54, 0)
kewastUnPackStats(): bad magic 1 (0x0000000067C4BE54, 0)
kewastUnPackStats(): bad magic 1 (0x0000000067C4BD04, 0)
kewastUnPackStats(): bad magic 1 (0x0000000067C4BD04, 0)
kewastUnPackStats(): bad magic 1 (0x0000000067C4BE44, 0)
kewastUnPackStats(): bad magic 1 (0x0000000067C4BE44, 0)
kewastUnPackStats(): bad magic 1 (0x0000000067C4BE49, 0)
kewastUnPackStats(): bad magic 1 (0x0000000067C4BE49, 0)
Fri Dec 27 09:18:18 2013
kewastUnPackStats(): bad magic 1 (0x000000006A699AF9, 0)
kewastUnPackStats(): bad magic 1 (0x000000006A699AF9, 0)
kewastUnPackStats(): bad magic 1 (0x000000006A699BF9, 0)
kewastUnPackStats(): bad magic 1 (0x000000006A699BF9, 0)
Fri Dec 27 09:33:52 2013
kewastUnPackStats(): bad magic 1 (0x0000000074FE9E6C, 0)
kewastUnPackStats(): bad magic 1 (0x0000000074FE9E6C, 0)
kewastUnPackStats(): bad magic 1 (0x0000000074FE9D44, 0)
kewastUnPackStats(): bad magic 1 (0x0000000074FE9D44, 0)
kewastUnPackStats(): bad magic 1 (0x0000000074FE9C0C, 0)
kewastUnPackStats(): bad magic 1 (0x0000000074FE9C0C, 0)
kewastUnPackStats(): bad magic 1 (0x0000000074FE9C14, 0)
kewastUnPackStats(): bad magic 1 (0x0000000074FE9C14, 0)

这已经是一个已知的BUG。
这时由于ASH信息读取处错误导致的。
It is caused by the variable part of the Active Session History rows (the module, action program, etc. information) not being stored properly, causing any read-back of this data through views like (G)V$ACTIVE_SESSION_HISTORY to fail.

还有一个变通的方案就是设置如下参数

Some suggest setting the control_management_pack_access to none as a temporary workaround:

alter system set control_management_pack_access='none' scope=memory;

这个BUG不会引起带严重的问题，打patch 8730312 可以解决问题。

参考文档：
"kewastUnPackStats(): bad magic 1 (0xXXXXXXXXX, 0)" in Alert Logfile After Upgrading to 11.2.0.1 (文档 ID 1227524.1)
Bug 8730312 - wrong Null ASH data may cause dumps and kew* messages in alert.log (文档 ID 8730312.8)
kewastUnPackStats(): bad magic 1 tips