BUG Kewastunpackstats(): Bad Magic 1 （xxx，0）

ALERT日誌出現：

kewastUnPackStats(): bad magic 1 (0x7f3521c489a0, 0)
kewastUnPackStats(): bad magic 1 (0x7f3521c489a0, 0)
kewastUnPackStats(): bad magic 1 (0x7f3521c458e0, 0)
kewastUnPackStats(): bad magic 1 (0x7f3521c458e0, 0)
kewastUnPackStats(): bad magic 1 (0x7f3521c458e0, 0)
kewastUnPackStats(): bad magic 1 (0x7f3521c458e0, 0)
kewastUnPackStats(): bad magic 1 (0x7f3521c458e0, 0)
kewastUnPackStats(): bad magic 1 (0x7f3521c458e0, 0)
kewastUnPackStats(): bad magic 1 (0x7f3521c458e0, 0)
kewastUnPackStats(): bad magic 1 (0x7f3521c458e0, 0)
kewastUnPackStats(): bad magic 1 (0x7f3521c48ad0, 0)
kewastUnPackStats(): bad magic 1 (0x7f3521c48ad0, 0)
kewastUnPackStats(): bad magic 1 (0x7f3521c48ad0, 0)
kewastUnPackStats(): bad magic 1 (0x7f3521c48ad0, 0)

SQL> select * from v$version;    

BANNER
--------------------------------------------------------------------------------
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
PL/SQL Release 11.2.0.1.0 - Production
CORE    11.2.0.1.0      Production
TNS for Linux: Version 11.2.0.1.0 - Production
NLSRTL Version 11.2.0.1.0 - Production

SQL> show parameter comp

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
cell_offload_compaction              string      ADAPTIVE
compatible                           string      11.2.0.0.0
nls_comp                             string      BINARY
plsql_v2_compatibility               boolean     FALSE

這是一個已知BUG導致的，主要是由於升級到11g後的一些變更導致的，以下是MOS的相關文檔：
Kewastunpackstats(): Bad Magic 1 (0x1108f7b87, 0) In Alert Logfile After Upgrading to 11.2.0.1 (Doc ID 1227524.1)

文檔提示，這是由於ASH信息讀取出錯導致的：

It is caused by the variable part of the Active Session History rows (the moduile, 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.

11.2.0.2之後的補丁集中被修正。