[CAY-1668] Memory Exhaustion Problem with Deserialization of ObjectContext

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.0.2
• Fix Version/s: 3.1B1
• Component/s: Core Library
• Environment: MacOS-X 10.7, Java 1.6.0_29, Simple Web Application run in the Maven plugin "jetty-maven-plugin"
• Assignee: Unassigned
• Reporter: Andrew Ponsonby Lindesay
• Created: 19/Feb/12 11:42
• Updated: 08/Mar/12 01:56
• Resolved: 08/Mar/12 01:56

Description

I am running a simple web application launched from maven using "jetty-maven-plugin". The simple web application has a Filter which does this;

1) Copies the HttpSession's attributes to a Map
2) Serializes the Map
3) Deserializes the Map
4) Copies the entries of the Map back into HttpSession

In each case, the ClassLoader should be the same (no stranded singletons etc...) and there is no "hot deploy" happening. The purpose of this undertaking is to ensure that the application is able to handle serialized sessions. In doing this experiment, I have observed a memory exhaustion issue around serializing and de-serializing ObjectContext. If I explicitly stop serializing "ObjectContext" then the problem stops.

Using jprofiler, I have observed that the memory consumption increases roughly exponentially in relation to the number of serialization/de-serialization events. Also from jquery analysis I see the memory is being referenced from;

org.apache.commons.collections.map.AbstractHashedMap$HashEntry[]
> org.apache.commons.collecitons.map.LRUMap
>> org.apache.cayenne.access.jdbc.SQLTemplateResourceManager
>>> ...velocity

The problem manifests itself quite quickly; a few dozen serialize + de-serialize phases.