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https://issues.apache.org/jira/browse/MAPREDUCE-6542?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15018754#comment-15018754
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Daniel Templeton commented on MAPREDUCE-6542:
---------------------------------------------
[~piaoyu zhang], that looks like a reasonable way to test. I wouldn't test
that the old method breaks -- we don't really care. What we want to prove is
that the new method doesn't break.
I would add two things to the test. First, instead of printing the times,
assert that they're equal:
{code}
Assert.assertTrue("Method returned inconsistent results indicative of a race
condition", time1.equals(time2))
{code}
I'd use the {{assertTrue()}} method instead of the {{assertEquals()}} method
because {{assertEquals()}} implies that the first argument is the canonically
correct value, but that's up to you.
Second, I'd start the {{run()}} method with a barrier so that you don't end up
with a case where the threads happen to all run serially as they're spawned.
It's probably pretty darned unlikely, but since the point of the test is to
make the threads try to stomp on each other, it may be worth it.
> HistoryViewer use SimpleDateFormat,But SimpleDateFormat is not threadsafe
> -------------------------------------------------------------------------
>
> Key: MAPREDUCE-6542
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-6542
> Project: Hadoop Map/Reduce
> Issue Type: Bug
> Components: jobhistoryserver
> Affects Versions: 2.2.0, 2.7.1
> Environment: CentOS6.5 Hadoop
> Reporter: zhangyubiao
> Assignee: zhangyubiao
> Attachments: MAPREDUCE-6542-v2.patch, MAPREDUCE-6542-v3.patch,
> MAPREDUCE-6542-v4.patch, MAPREDUCE-6542.patch
>
>
> I use SimpleDateFormat to Parse the JobHistory File before
> {code}
> private static final SimpleDateFormat dateFormat =
> new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
> public static String getJobDetail(JobInfo job) {
> StringBuffer jobDetails = new StringBuffer("");
> SummarizedJob ts = new SummarizedJob(job);
> jobDetails.append(job.getJobId().toString().trim()).append("\t");
> jobDetails.append(job.getUsername()).append("\t");
> jobDetails.append(job.getJobname().replaceAll("\\n",
> "")).append("\t");
> jobDetails.append(job.getJobQueueName()).append("\t");
> jobDetails.append(job.getPriority()).append("\t");
> jobDetails.append(job.getJobConfPath()).append("\t");
> jobDetails.append(job.getUberized()).append("\t");
>
> jobDetails.append(dateFormat.format(job.getSubmitTime())).append("\t");
>
> jobDetails.append(dateFormat.format(job.getLaunchTime())).append("\t");
>
> jobDetails.append(dateFormat.format(job.getFinishTime())).append("\t");
> return jobDetails.toString();
> }
> {code}
> But I find I query the SubmitTime and LaunchTime in hive and compare
> JobHistory File time , I find that the submitTime and launchTime was wrong.
> Finally,I change to use the FastDateFormat to parse the time format and the
> time become right
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