[OFBIZ-2186] OutOfMemory provoked by Cache overflow

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: Release Branch 4.0, Trunk
• Fix Version/s: Release Branch 09.04, Trunk
• Component/s: framework

Environment

Linux, JDK 1.5_15, Xmx set to 1156Mo

• Assignee: Jacques Le Roux
• Reporter: Philippe Mouawad
• Created: 13/Feb/09 12:24
• Updated: 19/Nov/09 08:41
• Resolved: 19/Nov/09 08:41

Description

In our production system, we had an OutOfMemoryError.
I analyzed the generated Heap Dump and found the following:
The cache entitycache.entity-list.default.ProductCategoryMember retains a heap of 369314128 Bytes.
The LRUMap hold by this object is occupying this space (369314128) and this object has a stange state:

• maxSize is set to 5000 (as set in the cache.properties)
• size is 128930 => PROBLEM

IN cache.properties:
entitycache.entity-list.default.ProductCategoryMember.expireTime=3600000
entitycache.entity-list.default.ProductCategoryMember.useSoftReference=true
entitycache.entity-list.default.ProductCategoryMember.maxInMemory=5000
entitycache.entity-list.default.ProductCategoryMember.maxSize=7500

I analyzed the code of LRUMap and its usage in CacheLineTable and IMHO the bug is a missing synchonized in get():
public CacheLine<V> get(Object key) {
if (key == null)

{ if (Debug.verboseOn()) Debug.logVerbose("In CacheLineTable tried to get with null key, using NullObject" + this.cacheName, module); }

return getNoCheck(key);
}

Since LRUMap extends LinkedHashMap, if you look at get method, it changes the state of the Map by calling e.recordAccess(this):
public V get(Object key)

{ Entry<K,V> e = (Entry<K,V>)getEntry(key); if (e == null) return null; e.recordAccess(this); return e.value; }

So the default of synchronization corrupts the state of LRUMap which grows indefinitely
I will submit a patch for this on the trunk.
Philippe
www.ubik-ingenierie.com

Issue Links

• is blocked by: OFBIZ-2124 Ofbiz freeze