SYMPTOM
Periodically, the Analytics application does not respond. Reloading the web page does not help. It is necessary to restart the Tomcat server.
SOLUTION
Try increasing the Java MaxPermSize parameter to 1024m.
This can be done in Tomcat's java command line (-XX:MaxPermSize=1024m) or in Tomcat settings (tomcat7w.exe or tomcat8w.exe).