Our web application runs on Apache-Tomcat-8.5.5 and java 1.8 (linux-amd64). Application uses hikari db connection pool with oracle database.
After a random period of time (3-4 weeks), we get "java.lang.OutOfMemoryError: Compressed class space" exception and then server hangs and becomes un-responsive. This lasts until we re-start the server.
With the memory exception, active hikari connection count had increased until the re-start, and also found that there were few threads stuck(running more than 5 mins).
After analysing the heap-dump on memory exception, memory utilization seems pretty normal and has not reached the limits(JAVA_OPTS="$JAVA_OPTS -XX:NewSize=2048m -XX:MaxNewSize=2048m -Xms6144m -Xmx6144m -XX:PermSize=200m -XX:MaxPermSize=1024m )
can somebody tell what causes this or what would be helpful to identify the root cause?