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https://issues.apache.org/jira/browse/CASSANDRA-15676?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17102135#comment-17102135
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Yifan Cai commented on CASSANDRA-15676:
---------------------------------------
Interesting approach. If I am reading the code correctly, the test makes sure
the response from peers are always false. So the first CAS backs off and
returns unknown result.
I think overwriting the response is not necessary. You can precisely construct
such a contention condition with {{CountDownLatch}} and 2 filters.
The test can block the PROPOSE req until the second CAS is completed. So the
first CAS is guaranteed to get unknown result. Something looks like the
following. Therefore, you do not need to open the access to methods in
{{Instance.java}} and {{DistributedTestSnitch.java}} and overwrites messages.
{code:java}
CountDownLatch ready = new CountDownLatch(1);
cluster.filters().verbs(Verb.PAXOS_PROPOSE_REQ.id).from(1).to(2,
3).messagesMatching((from, to, msg) -> {
if (to == 2)
{
// Inject a single CAS request in-between prepare and
propose phases
cluster.coordinator(2).execute(mkCasInsertQuery((a) -> pk,
1, 2),
ConsistencyLevel.QUORUM);
ready.countDown();
} else {
Uninterruptibles.awaitUninterruptibly(ready);
}
return false;
}).drop(); // the message intercepting syntax is sort of
confusing...
{code}
> flaky test testWriteUnknownResult-
> org.apache.cassandra.distributed.test.CasWriteTest
> -------------------------------------------------------------------------------------
>
> Key: CASSANDRA-15676
> URL: https://issues.apache.org/jira/browse/CASSANDRA-15676
> Project: Cassandra
> Issue Type: Task
> Components: Test/dtest
> Reporter: Kevin Gallardo
> Assignee: Gianluca Righetto
> Priority: Normal
> Fix For: 4.0-alpha
>
> Attachments: Screen Shot 2020-05-07 at 7.25.19 PM.png
>
>
> Failure observed in:
> https://app.circleci.com/pipelines/github/newkek/cassandra/33/workflows/54007cf7-4424-4ec1-9655-665f6044e6d1/jobs/187/tests
> {noformat}
> testWriteUnknownResult - org.apache.cassandra.distributed.test.CasWriteTest
> junit.framework.AssertionFailedError: Expecting cause to be
> CasWriteUncertainException
> at
> org.apache.cassandra.distributed.test.CasWriteTest.testWriteUnknownResult(CasWriteTest.java:257)
> at
> java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
> at
> java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
> at
> java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
> {noformat}
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