High consumption of Java Heap Old generation

6.4.1

Issue

The Java Heap Old generation usage is constantly above 99% 

Impact

The high usage of Java Heap old generation lead to a full Garbage Collection every minute, hence the performance of the author instance is degraded

Solution

The issue comes from a memory leak in cached adapters in Sling. 
This has been solved through https://issues.apache.org/jira/browse/SLING-7586 and included in AEM 6.5 and backported to 6.4.4 under the references GRANITE-23537 / NPR-27636
As an immediate solution, updating the 2 bundles org.apache.sling.models.api to v1.3.8 and or.apache.sling.models.impl to v1.4.10

These 2 bundles are part of a support fix (see above)