[jira] [Commented] (HADOOP-9916) Race condition in ipc.Client causes TestIPC timeout

["Hadoop QA (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HADOOP-9916?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13755773#comment-13755773 ] 

Hadoop QA commented on HADOOP-9916:
-----------------------------------

{color:green}+1 overall{color}.  Here are the results of testing the latest attachment 
  http://issues.apache.org/jira/secure/attachment/12600999/HADOOP-9916.v1.patch
  against trunk revision .

    {color:green}+1 @author{color}.  The patch does not contain any @author tags.

    {color:green}+1 tests included{color}.  The patch appears to include 1 new or modified test files.

    {color:green}+1 javac{color}.  The applied patch does not increase the total number of javac compiler warnings.

    {color:green}+1 javadoc{color}.  The javadoc tool did not generate any warning messages.

    {color:green}+1 eclipse:eclipse{color}.  The patch built with eclipse:eclipse.

    {color:green}+1 findbugs{color}.  The patch does not introduce any new Findbugs (version 1.3.9) warnings.

    {color:green}+1 release audit{color}.  The applied patch does not increase the total number of release audit warnings.

    {color:green}+1 core tests{color}.  The patch passed unit tests in hadoop-common-project/hadoop-common.

    {color:green}+1 contrib tests{color}.  The patch passed contrib unit tests.

Test results: https://builds.apache.org/job/PreCommit-HADOOP-Build/3049//testReport/
Console output: https://builds.apache.org/job/PreCommit-HADOOP-Build/3049//console

This message is automatically generated.
                
> Race condition in ipc.Client causes TestIPC timeout
> ---------------------------------------------------
>
>                 Key: HADOOP-9916
>                 URL: https://issues.apache.org/jira/browse/HADOOP-9916
>             Project: Hadoop Common
>          Issue Type: Bug
>            Reporter: Binglin Chang
>            Assignee: Binglin Chang
>            Priority: Minor
>         Attachments: HADOOP-9916.v1.patch
>
>
> TestIPC timeouts occasionally, for example: 
> [https://issues.apache.org/jira/browse/HDFS-5130?focusedCommentId=13749870&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-13749870]
> [https://issues.apache.org/jira/browse/HADOOP-9915?focusedCommentId=13753302&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-13753302]
> Look into the code, there is race condition in oah.ipc.Client, the race condition happen between RPC call thread and connection read response thread:
> {code}
>         if (status == RpcStatusProto.SUCCESS) {
>           Writable value = ReflectionUtils.newInstance(valueClass, conf);
>           value.readFields(in);                 // read value
>           call.setRpcResponse(value);
>           calls.remove(callId);
> {code}
> Read Thread: 
> Connection.receiveRpcResponse-> call.setRpcResponse(value) -> notify Call Thread
> Call Thread:
> Client.call -> Connection.addCall(retry with the same callId) -> notify read thread
> Read Thread:
> calls.remove(callId) # intend to remove old call, but removes newly added call...
> Connection.waitForWork end up wait maxIdleTime and close the connection. The call never get response and dead.
> The problem doesn't show because previously callId is unique, we never accidentally remove newly added calls, but when retry added this race condition became possible.
> To solve this, we can simply change order, remove the call first, then notify call thread.
> Note there are many places need this order change(normal case, error case, cleanup case)
> And there are some minor issues in TestIPC:
> 1. there are two method with same name:
>    void testSerial()
>    void testSerial(int handlerCount, boolean handlerSleep, ...)
>    the second is not a test case(so should not use testXXX prefix), but somehow it causes testSerial(first one) run two times, see test report:
> {code}
>   <testcase time="26.896" classname="org.apache.hadoop.ipc.TestIPC" name="testSerial"/>
>   <testcase time="25.426" classname="org.apache.hadoop.ipc.TestIPC" name="testSerial"/>
> {code}
> 2. timeout annotation should be added, so next time related log is available.

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