[CAY-845] DataContext.localObject() object update race condition

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.0
• Fix Version/s: 3.0M2
• Component/s: Core Library
• Environment: 3.0 M1
• Assignee: Andrus Adamchik
• Reporter: Andrus Adamchik
• Created: 07/Aug/07 16:32
• Updated: 09/Nov/08 01:07
• Resolved: 07/Aug/07 17:06

Description

I've been using a shared DataContext in a read-only multi-threaded app. Looks like I've stumbled upon a race condition in resolving to-one relationship. I've noticed applications occasionally spinning out of control with load averages on the box shooting to 50 and higher. A "kill -QUIT" on the Jetty server shows a bunch of threads executing the code shown in the stack below. Googling for "java.util.HashMap.get(HashMap.java:346)" shows that this is a common race condition (looks like HashMap.get() is stuck in an endless loop). The easiest solution is to use the common objectstore lock spanning most of the DataContext.localObject(..).

at java.util.HashMap.get(HashMap.java:346)
at org.apache.cayenne.CayenneDataObject.readPropertyDirectly(CayenneDataObject.java:212)
at org.apache.cayenne.reflect.generic.DataObjectBaseProperty.readPropertyDirectly(DataObjectBaseProperty.java:69)
at org.apache.cayenne.reflect.generic.DataObjectToManyProperty.injectValueHolder(DataObjectToManyProperty.java:98)
at org.apache.cayenne.reflect.PersistentDescriptor.injectValueHolders(PersistentDescriptor.java:247)
at org.apache.cayenne.reflect.LazyClassDescriptorDecorator.injectValueHolders(LazyClassDescriptorDecorator.java:113)
at org.apache.cayenne.access.DataContext.localObject(DataContext.java:1679)
at org.apache.cayenne.access.DataDomainQueryAction.interceptRelationshipQuery(DataDomainQueryAction.java:228)
at org.apache.cayenne.access.DataDomainQueryAction.execute(DataDomainQueryAction.java:113)
at org.apache.cayenne.access.DataDomain.onQuery(DataDomain.java:722)
at org.apache.cayenne.util.ObjectContextQueryAction.runQuery(ObjectContextQueryAction.java:282)
at org.apache.cayenne.access.DataContextQueryAction.execute(DataContextQueryAction.java:59)
at org.apache.cayenne.access.DataContext.onQuery(DataContext.java:1321)
at org.apache.cayenne.access.DataContext.performQuery(DataContext.java:1310)
at org.apache.cayenne.access.DataContextFaults$ToOneFault.doResolveFault(DataContextFaults.java:113)
at org.apache.cayenne.access.DataContextFaults$ToOneFault.resolveFault(DataContextFaults.java:86)
at org.apache.cayenne.CayenneDataObject.readProperty(CayenneDataObject.java:204)