cpugputpu created KYLIN-4386:
--------------------------------
Summary: Use LinkedHashMap for a deterministic order in test
Key: KYLIN-4386
URL: https://issues.apache.org/jira/browse/KYLIN-4386
Project: Kylin
Issue Type: Bug
Components: Tools, Build and Test
Reporter: cpugputpu
The tests in
_org.apache.kylin.stream.coordinator.CoordinatorTest#testReassignFailOnStartNew_
and
_org.apache.kylin.stream.coordinator.CoordinatorTest#testReassignFailOnStopAndSync_
will fail when making the following assertions:
_assertSame(ClusterStateException.ClusterState.ROLLBACK_FAILED,
rune.getClusterState());_
_assertSame(ClusterStateException.TransactionStep.STOP_AND_SNYC,
rune.getTransactionStep());_
The failure is reported as follows:
java.lang.Exception: Unexpected exception,
expected<org.apache.kylin.stream.coordinator.exception.ClusterStateException>
but was<java.lang.AssertionError>
at
org.apache.kylin.stream.coordinator.CoordinatorTest.testReassignFailOnStartNew(CoordinatorTest.java:271)
After my analysis, I find that the root cause is that the variable
_newAssignMap_ is a HashMap, which makes no guarantee about the order when
iterating in
_org.apache.kylin.stream.coordinator.Coordinator.doReassign(Coordinator.java:516)_
The specification about HashMap says that "this class makes no guarantees as to
the order of the map; in particular, it does not guarantee that the order will
remain constant over time". The documentation is here for your reference:
[https://docs.oracle.com/javase/8/docs/api/java/util/HashMap.html]
The fix is to use LinkedHashMap instead of HashMap so that the
non-deterministic behaviour is eliminated. It will not affect the performance
and can make the tests more stable.
--
This message was sent by Atlassian Jira
(v8.3.4#803005)
