Bugs item #747143, was opened at 2003-06-01 13:57 Message generated for change (Tracker Item Submitted) made by Item Submitter You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=376685&aid=747143&group_id=22866
Category: JBossCMP Group: v3.2 Status: Open Resolution: None Priority: 5 Submitted By: Andrew Veliath (andrewtv) Assigned to: Nobody/Anonymous (nobody) Summary: CMR exception when many threads get 1-side from N-side Initial Comment: OS: Linux JDK: 1.4.0_04 We have experienced a new exception going from 3.2.0RC1 to 3.2.1 regarding CMR's under load (with MySQL and InnoDB). Here is the scenario: there are 2 EJB 2.0 beans using CMR, Partition and StationGroup (there are many more, but use these two for example). There is a 1-N relation from Partition to StationGroup, and there is some code that retrieves the PartitionLocal from the station group side (i.e. retrieving the 1-side local intf from the N-side intf). All methods in Partition and StationGroup have the "Required" trans-attribute, and non are marked read-only. Note this problem does not occur in 3.2.0RC1, but in 3.2.1 it appears to happen in about 1/500 cases under moderate load. Since it is hard to reproduce it sounds like some sort of race or synchronization issue. The problem appears to happen here--it seems that doing "partLocal = sg.getPartition()" (N-side retrieving 1-side local) to retrieve the PartitionLocal seems to lock and load the entire Partition bean, however it does not appear to lock Partition properly and multiple threads that call sg.getPartition can somehow interfere with each other (i.e. many N-side threads call get1Side()), causing JDBCCMRFieldBridge.FieldState to be invalidate()d and the other threads calling sg.getPartition() from different StationGroups will start throwing NPEs (in loadRelations typically since setHandle[0] is then null I assume), ConcurrentModificationExceptions, etc. This is sort of the *opposite* test of the current CMRStressTestCase (many N-side threads getting the 1-side, instead of many threads getting the N-side from the 1-side), and the only difference is that our get methods are not marked as read-only at the moment. I agree a test case will help for this. ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=376685&aid=747143&group_id=22866 ------------------------------------------------------- This SF.net email is sponsored by: eBay Get office equipment for less on eBay! http://adfarm.mediaplex.com/ad/ck/711-11697-6916-5 _______________________________________________ Jboss-development mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/jboss-development
