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Tomcat CPU leak - CSCue33973


Hello Guys,

One of our customer is facing an issue with his Call Manager. About 1 times on 2/3 weeks the CUP is raising until the limit (100%) and we need to restart the Tomcat service.

Based on bug tool I found that bug ID:  CSCue33973


High CPU and memory usage when AXL is enabled and running for a long time.


It  was discovered that the ArrayList hostNameList in class had 14,847 entries in it.  The  list contained the server ip addresses multiple times.  This ArrayList  is supposed to hold a list of servers active in the cluster.

Upon  looking at the source code it was discovered that the logic to populate  that list was wrong and not only would that list continue to grow  without bound or until Tomcat was restarted, but every 5 seconds the AXL  Throttler will iterate that list and try to connect to each server in  that list and query the database to check the dblcnqueue count.  Not  only was this happening 14,847 times every five seconds, that code block  is synchronized and will block until it is done executing.

The longer between Tomcat restarts, the worse the problem is.

Versions Affected:





Someone can say me how I can check the list mentionned in the bug detail to see if we are facing that bug or not ?


Hervé Jacquemin


Joseph Martini
Cisco Employee
Cisco Employee

If you post your full CUCM version (example I'll let you know if your version has the fix or not for that defect.  I'll be checking the fixed versions against your version to detemine if you have the fix or now.

We are running 8.6.2-22900-9.

In the Bug detail it's solved in realease (newer than us).

Hello hjacquemin,

I can only tell you that  8.6(2) is included in the Verified Releases, however after checking the release notes i do not see the bug stated:





did you have time to check if my release is impacted?



Yes I checked and your version contains the fix for CSCue33973 so it should not be impacted by that defect.

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