[ 
https://issues.apache.org/jira/browse/HADOOP-11361?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15374384#comment-15374384
 ] 

Yongjun Zhang commented on HADOOP-11361:
----------------------------------------

Thanks guys, that's another improvement!

One little thing:
{code}
    synchronized (this) {
      if (lastRecs != null) {
        updateAttrCache(lastRecs);
        if (getAllMetrics) {  <====== this check is redundant
          updateInfoCache(lastRecs);
        }
      }
      jmxCacheTS = Time.now();
      lastRecsCleared = true;
    }
{code}
The {{if (getAllMetrics)}} in the above code is redundant, because it has to be 
true when {{lastRecs}} is not null.

Thanks.


> Fix a race condition in MetricsSourceAdapter.updateJmxCache
> -----------------------------------------------------------
>
>                 Key: HADOOP-11361
>                 URL: https://issues.apache.org/jira/browse/HADOOP-11361
>             Project: Hadoop Common
>          Issue Type: Bug
>    Affects Versions: 2.4.1, 2.5.1, 2.6.0
>            Reporter: Brahma Reddy Battula
>            Assignee: Brahma Reddy Battula
>         Attachments: HADOOP-111361-003.patch, HADOOP-11361-002.patch, 
> HADOOP-11361-004.patch, HADOOP-11361-005.patch, HADOOP-11361-005.patch, 
> HADOOP-11361-006.patch, HADOOP-11361.patch, HDFS-7487.patch
>
>
> {noformat}
> Caused by: java.lang.NullPointerException
>       at 
> org.apache.hadoop.metrics2.impl.MetricsSourceAdapter.updateAttrCache(MetricsSourceAdapter.java:247)
>       at 
> org.apache.hadoop.metrics2.impl.MetricsSourceAdapter.updateJmxCache(MetricsSourceAdapter.java:177)
>       at 
> org.apache.hadoop.metrics2.impl.MetricsSourceAdapter.getAttribute(MetricsSourceAdapter.java:102)
>       at 
> com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.getAttribute(DefaultMBeanServerInterceptor.java:647)
> {noformat}



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)

---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]

Reply via email to