Hi,

The problem happens when you try to delete a second process wich has the same business key as a fisrt terminated process.

Stéphane

<process name="DeleteProcessTest" xmlns="http://jbpm.org/4.4/jpdl">
   <start name="start1" g="24,36,48,48">
      <transition to="task1"/>
   </start>
   <task name="task1" g="120,36,92,52">
      <transition to="end1"/>
   </task>
   <end name="end1" g="264,36,48,48"/>
</process>

public class DeleteProcessInstanceTest extends JbpmTestCase {
    private String deploymentId;

    @Override
    protected void setUp() throws Exception {
        super.setUp();
        deploymentId = repositoryService.createDeployment().addResourceFromClasspath("DeleteProcessTest.jpdl.xml").deploy();
    }

    @Override
    protected void tearDown() throws Exception {
        repositoryService.deleteDeploymentCascade(deploymentId);
        super.tearDown();

    }

    public void testDeleteProcess() throws Exception {
        // Start the first process
        ProcessInstance processInstance = executionService.startProcessInstanceByKey("DeleteProcessTest", "Key");
        Task task = taskService.createTaskQuery().processInstanceId(processInstance.getId()).uniqueResult();
        taskService.completeTask(task.getId());     

        // First process is terminated
        Assert.assertNull(executionService.findExecutionById(processInstance.getId()));

        // Start second process
        processInstance = executionService.startProcessInstanceByKey("DeleteProcessTest", "Key");

        // Try to delete
        executionService.deleteProcessInstanceCascade(processInstance.getId());
    }
}

16:09:02,781 INFO  [DefaultCommandService] exception while executing command org.jbpm.pvm.internal.cmd.DeleteProcessInstance@30f82c
org.hibernate.NonUniqueResultException: query did not return a unique result: 4
        at org.hibernate.impl.AbstractQueryImpl.uniqueElement(AbstractQueryImpl.java:820)
        at org.hibernate.impl.CriteriaImpl.uniqueResult(CriteriaImpl.java:305)
        at org.jbpm.pvm.internal.hibernate.DbSessionImpl.findHistoryProcessInstanceById(DbSessionImpl.java:231)
        at org.jbpm.pvm.internal.hibernate.DbSessionImpl.deleteProcessInstance(DbSessionImpl.java:174)