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Peter Bacsko updated OOZIE-2550: -------------------------------- Attachment: (was: OOZIE-2550-002.patch) > Flaky tests in TestZKUUIDService.java > ------------------------------------- > > Key: OOZIE-2550 > URL: https://issues.apache.org/jira/browse/OOZIE-2550 > Project: Oozie > Issue Type: Bug > Components: tests > Reporter: Peter Bacsko > Assignee: Peter Bacsko > Priority: Minor > Attachments: OOZIE-2550-001.patch, OOZIE-2550-002.patch > > > 1. Test case testMultipleIDGeneration_withMultiThread in TestZKUUIDService > uses an ArrayList which is written by two threads simultaneously. This is > dangerous and the list must be externally synchronized to prevent race > conditions. > Another problem is that you cannot put items at arbitrary indexes in an > ArrayList. For example, if the list is empty, the following code throws > ArrayIndexOutOfBoundException: > {code} > List<Boolean> test = new ArrayList<>(10000); > test.add(22, true); > {code} > In an unlucky scheduling event, the following can happen: > 1. The list has a certain number of elements, the value of "size" inside the > list is 1000 > 2. Thread-1 retrieves the next ID from ZK UUID service, which is 1001 > 3. Thread-2 retrieves the next ID from ZK UUID service, which is 1002 > 4. Thread-2 runs faster than Thread-1 and tries to call {{list.add(1002, > true)}} which fails. > The following error was caught during a test run: > {code} > Tests run: 8, Failures: 0, Errors: 1, Skipped: 0, Time elapsed: 53.571 sec > <<< FAILURE! > testMultipleIDGeneration_withMultiThread(org.apache.oozie.service.TestZKUUIDService) > Time elapsed: 0.02 sec <<< ERROR! > java.lang.IndexOutOfBoundsException: Index: 89, Size: 89 > at java.util.ArrayList.rangeCheck(ArrayList.java:653) > at java.util.ArrayList.get(ArrayList.java:429) > at > org.apache.oozie.service.TestZKUUIDService.testMultipleIDGeneration_withMultiThread(TestZKUUIDService.java:134) > at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) > at > sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) > at > sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) > at java.lang.reflect.Method.invoke(Method.java:498) > at junit.framework.TestCase.runTest(TestCase.java:168) > at junit.framework.TestCase.runBare(TestCase.java:134) > at junit.framework.TestResult$1.protect(TestResult.java:110) > at junit.framework.TestResult.runProtected(TestResult.java:128) > at junit.framework.TestResult.run(TestResult.java:113) > at junit.framework.TestCase.run(TestCase.java:124) > at junit.framework.TestSuite.runTest(TestSuite.java:243) > at junit.framework.TestSuite.run(TestSuite.java:238) > at > org.junit.internal.runners.JUnit38ClassRunner.run(JUnit38ClassRunner.java:83) > at org.junit.runners.Suite.runChild(Suite.java:128) > at org.junit.runners.Suite.runChild(Suite.java:24) > at org.junit.runners.ParentRunner$3.run(ParentRunner.java:231) > at > java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) > at java.util.concurrent.FutureTask.run(FutureTask.java:266) > at > java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) > at > java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) > at java.lang.Thread.run(Thread.java:745) > {code} > 2. The order in which the tests are executed is random. The problem is that > testResetSequence sets the maximum sequence number to 900. Because this value > is stored in a static variable inside ZKUUIDService, it affects > testIDGeneration and testMultipleIDGeneration if these tests are run after > testResetSequence. -- This message was sent by Atlassian JIRA (v6.3.4#6332)