[
https://issues.apache.org/jira/browse/HDFS-9422?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
He Liangliang updated HDFS-9422:
--------------------------------
Attachment: HDFS-9422.patch
The lock is unnecessary:
1. getFinalizedBlocks is thread safe and the returned block list is a deep
copy, so the lock does not protect any extra shared data
2. the latter checkAndUpdate call is also thread safe and will filter out the
false alarm
> Unnecessary FsDatasetImpl locking in DirectoryScanner cause periodic datanode
> pauses
> ------------------------------------------------------------------------------------
>
> Key: HDFS-9422
> URL: https://issues.apache.org/jira/browse/HDFS-9422
> Project: Hadoop HDFS
> Issue Type: Bug
> Reporter: He Liangliang
> Assignee: He Liangliang
> Attachments: HDFS-9422.patch
>
>
> In DirectoryScanner, the scan call hold the global dataset lock for quite
> long time (typically > 5 secs for 500k blocks). This will stuck the client
> which need acquire this lock. For applications like HBase, this will affect
> the latency. In fact, this lock is unnecessary.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
