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Home » Eclipse Projects » EclipseLink » deadlock issues in eclipselink version 2.4.2(Are there any known deadlock issues in eclipselink v2.4.2)
deadlock issues in eclipselink version 2.4.2 [message #1404620] Mon, 04 August 2014 14:06 Go to next message
Prakash Guggilam is currently offline Prakash GuggilamFriend
Messages: 1
Registered: August 2014
Junior Member
Hi All,
We are in process of picking up a right ORM for our project and are more inclined to use the licensed eclipselink v2.4.2. Before going ahead with the implementation, we searched for some known security/critical issues (if any) in this version and found a quite few of them. I didn't get good information over the net on if these are some valid major issues to be worried about. And if these issues has been fixed in any subsequent releases or if any patches are available or not. Below are the list of issues we found:

Bug 309822 - Deadlock when returning Entities from a remote method call. (The version affected by this issue is unspecified)
Bug 394585 - Deadlock between ConcurrenctManager.acquire and IndirectList.getDelegate due to dropped read lock
Bug 440085 - Deadlock in ConcurrencyManager.releaseDefferedLock
Bug 331094 - PersistenceProviderResolverHolder is thread unsafe
Bug 414756 - Wrong Results by Concurrent JPQL Queries on Entity with TABLE_PER_CLASS Mapping
Bug 416837 - JPQL Parser bug: Explicit long literals will lead to wrong data

There is no enough information available in the bugs files in bugzilla too. So, could some one please share the information on if these bugs are really valid. And if yes, what all the scenarios which gets affected?
Re: deadlock issues in eclipselink version 2.4.2 [message #1405076 is a reply to message #1404620] Wed, 06 August 2014 14:19 Go to previous message
Chris Delahunt is currently offline Chris DelahuntFriend
Messages: 1078
Registered: July 2009
Senior Member
As you say, there really isn't alot of information in the bugs to go on, and most have not yet been triaged so there is no way of saying if there was a configuration issue or an actual issue with EclipseLink.

Locking issues are uncommon, but can occur in any system. When using EclipseLink they can appear to occur in the ConcurrencyManager class which is used to restrict thread access to objects in the shared cache until they are completely built. What is somtimes confused as a deadlock though is sometimes just a slow down or bottleneck - repeatedly reading the same root object graph from the shared cache on multiple threads will create a bottleneck on refreshing the root object. There is a wiki to help diagnose issues and find solutions: https://wiki.eclipse.org/EclipseLink/FAQ/JPA#How_to_diagnose_and_resolve_hangs_and_deadlocks.3F

The PersistenceProviderResolverHolder being unsafe doesn't seem to be a major issue to anyone, and TABLE_PER_CLASS inheritance is not the recommended inheritance strategy - the bug seems fixed from what was filed though.

This is the first I've seen the JPQL Parser bug, and might be worked around by simply adding the value as a parameter to the query instead of in line with the JPQL.
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