Team, We just had an OOM incident in our dev environments after upgrading from Camel 2.10.3 to 2.13.1. Heap settings have remained untouched.
A heap dump showed millions of DefaultMessageHistory instances retained (see screenshot), along with their corresponding Date and StopWatch instances. Obviously our first solution will be to disable message history in all contexts. Digging deeper, I'm utterly confused because I don't seem to find the GC roots that are keeping these objects alive. OQL query for VisualVM: select x from org.apache.camel.impl.DefaultMessageHistory x where count(referrers(x)) > 0 returns many objects, which is good. However, they are referenced by some Object[] which in turn has no referrers (!), see screenshot. Using the "Find nearest GC root" feature yields no results either. This mysterious Object[] seems to be filled from position 4072 onwards (see screenshot), it has 9k+ items... Perhaps some kind of Queue? There are many more Object[] arrays storing DefaultMessageHistory instances too. What's your take? Have you come across such an issue before? Someone who is outright familiar with the internal workings of the Message History functionality has any clue what's the purpose of this array? Thanks, Raúl. [image: Inline image 3] [image: Inline image 1] [image: Inline image 2] *Raúl Kripalani* Apache Camel PMC Member & Committer | Enterprise Architect, Open Source Integration specialist http://about.me/raulkripalani | http://www.linkedin.com/in/raulkripalani http://blog.raulkr.net | twitter: @raulvk
