[
https://issues.apache.org/jira/browse/HDFS-14074?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16926346#comment-16926346
]
Zhankun Tang commented on HDFS-14074:
-------------------------------------
[~jojochuang], cool. Thanks!
> DataNode runs async disk checks maybe throws NullPointerException, and
> DataNode failed to register to NameSpace.
> ------------------------------------------------------------------------------------------------------------------
>
> Key: HDFS-14074
> URL: https://issues.apache.org/jira/browse/HDFS-14074
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: hdfs
> Affects Versions: 2.8.0, 3.0.0
> Environment: hadoop-2.7.3, hadoop-2.8.0
> Reporter: guangyi lu
> Assignee: guangyi lu
> Priority: Major
> Labels: HDFS, HDFS-11114
> Fix For: 3.3.0, 3.2.1, 3.1.3
>
> Attachments: HDFS-14074-latest.patch, HDFS-14074.patch,
> WechatIMG83.jpeg
>
> Original Estimate: 48h
> Remaining Estimate: 48h
>
> In ThrottledAsyncChecker class，it members of the completedChecks is
> WeakHashMap, its definition is as follows：
> this.completedChecks = new WeakHashMap<>();
> and one of its uses is as follows in schedule method:
> if (completedChecks.containsKey(target)) {
> // here may be happen garbage collection，and result may be null.
> final LastCheckResult<V> result = completedChecks.get(target);
>
> final long msSinceLastCheck = timer.monotonicNow() -
> result.completedAt;
> 。。。。
> }
> after "completedChecks.containsKey(target)"， may be happen garbage
> collection， and result may be null.
> the solution is：
> this.completedChecks = new ReferenceMap(1, 1);
> or
> this.completedChecks = new HashMap<>();
>
--
This message was sent by Atlassian Jira
(v8.3.2#803003)
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
