The meaning of "Duplicate session ids detected" APM CE (CEM) warnings. What to do if they occur.

Document ID : KB000011541
Last Modified Date : 14/02/2018
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Introduction:

  This is a common error message that can happen frequently in the APM CE (CEM) Events Tab of the MOM GUI. As a result, it is a concern to some APM administrators.

Question:

What do the warning messages "Duplicate session ids detected" mean in the CEM console and should I be concerned?

Environment:
All supported APM releases.
Answer:

 These warning messages can be due to the following:

1. The Business Application Session ID (Administration/Business Applications/Session Identification tab) is not unique for the monitored application. Selecting a good session identifier for the life of the transaction can eliminate this message as well as the "unidentified user" issue.

2. The Business Application Session Timeout (Administration/Business Applications/General tab) has a different value to the session timeout defined for the monitored application on its web server.

3. Duplicate monitoring of traffic due to having multiple TIMs receiving the same traffic. If it is not possible to split the traffic to the TIMs, this can be controlled on each TIM by adding Web Server Filters under the Setup.

 

 

Additional Information:

The warning messages actually arise from the fact that the EM (TESS) tries to insert the session id data into table ts_us_sessions_map but encounters a unique index violation because a row already exists for the session ID associated to that business application in that table (the unique index is comprised of the 3 columns ts_app_id, ts_session_id, and ts_interim_session_id).

Sometimes the warnings will still persist even if all 3 checks have been made. This is often due to a situation where a web server is re-using session ids for different end-user ids which CEM cannot handle.

In summary there is no loss of CEM functionality which is why the message has severity level of warning rather than errror. The events are to ensure the above checks have been covered off and they cannot be disabled.