在alert文件中最近发现大量kewastUnPackStats(): bad magic的告警信息，查询MOS发现是Active Session History的bug引起
The cause of this problem has been identified in Bug:8967729 which has been closed as duplicate of un-published bug 8730312. 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.
The issue has been fixed in the upcoming Oracle12c release and the 18.104.22.168 and higher patchsets. The solution is to install the 22.214.171.124 or higher patchset.For any environments where this is not available, apply Patch:8730312As one-off patches are not subjected to the same rigorous level of testing as done for Oracle Server patch sets, you are encouraged to install and test this patch in a test environment prior to full production implementation.
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