DeadlockException

Question

Hi, using DPL and 3.1.0 on Win32 platform JDK 1.5.09-b -- simple unit test that does the following:
1) put an object into DPL
2) get it back out and do equality check
3) delete the object from DPL
Step 3 causes a DeadlockException.
Stacktrace follows:
junit.framework.AssertionFailedError: Exception in test: DatabaseException occurred: com.sleepycat.je.DeadlockException: (JE 3.1.0) Lock expired. Locker 14_main_AutoTxn: waited for lock on database=persist#DalStore#FeatureImpl#featureCode node=52 type=WRITE grant=WAIT_NEW timeoutMillis=500 startTime=1161798879187 endTime=1161798880187
Owners: [<LockInfo locker="-1_main_ThreadLocker" type="READ"/>, <LockInfo locker="-1_main_ThreadLocker" type="READ"/>]
Waiters: []
     at junit.framework.Assert.fail(Assert.java:47)
     at TestBerkeleyCache.testPutFeature(TestBerkeleyCache.java:93)
     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
     at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
     at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
     at java.lang.reflect.Method.invoke(Unknown Source)
     at junit.framework.TestCase.runTest(TestCase.java:154)
     at junit.framework.TestCase.runBare(TestCase.java:127)
     at junit.framework.TestResult$1.protect(TestResult.java:106)
     at junit.framework.TestResult.runProtected(TestResult.java:124)
     at junit.framework.TestResult.run(TestResult.java:109)
     at junit.framework.TestCase.run(TestCase.java:118)
     at junit.framework.TestSuite.runTest(TestSuite.java:208)
     at junit.framework.TestSuite.run(TestSuite.java:203)
     at org.eclipse.jdt.internal.junit.runner.junit3.JUnit3TestReference.run(JUnit3TestReference.java:128)
     at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
     at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:460)
     at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:673)
     at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:386)
     at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:196)
Here is the method that causes the exception ->
public void remove(long featureId, int featureCode) throws TADalException {
     EntityJoin<Long, FeatureImpl> join = new EntityJoin<Long, FeatureImpl>(featureByPrimaryKey);
     join.addCondition(featureById, featureId);
     join.addCondition(featureByCode, featureCode);
     ForwardCursor<Long> cursor = null;
     try {
         cursor = join.keys();
         long id = cursor.next();
         featureByPrimaryKey.delete(id);
     } catch (DatabaseException e) {
         throw new TADalException("DatabaseException occurred: " + e);
     } finally {
         try {
          if (cursor != null) {
              cursor.close();
         } catch (DatabaseException dbe) {
          throw new TADalException("DatabaseException occurred: " + dbe);
    }Any ideas on whether I'm doing something I shouldn't here? Thanks in advance...
-davis

Answer 1

Hi Mark --
the problem I have is that EntityCursor is a
sub-interface of ForwardCursor and ForwardCursor has
no delete operation.I'm sorry, I didn't even notice that your cursor was returned with a join.
How to get at delete( ) then?If you want to delete/modify/insert while a join cursor is open, and you want to use a transactional store, then you will need to:
1) Before doing the join, start a transaction by calling Environment.beginTransaction.
2) Pass the transaction to join.keys() so that the transaction is used by the join cursor.
3) Pass the transaction to featureByPrimaryKey.delete() also.
4) When you're done, after closing all cursors, commit the transaction by calling Transaction.commit.
In general, when you are using transactions, if a cursor is open in the current thread and you perform other non-cursor operations in that thread, all operations must use the same transaction. In other words, you cannot use auto-commit for the delete operation when a cursor is open. (Auto-commit is the default when no transaction is passed and the store is transactional.)
Mark