[ 
https://issues.apache.org/jira/browse/OOZIE-2550?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
 ]

Peter Bacsko updated OOZIE-2550:
--------------------------------
    Attachment: 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)

Reply via email to