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https://issues.apache.org/jira/browse/HDFS-17320?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17802378#comment-17802378
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ASF GitHub Bot commented on HDFS-17320:
---------------------------------------
KeeProMise commented on code in PR #6403:
URL: https://github.com/apache/hadoop/pull/6403#discussion_r1441243319
##########
hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/DFSInputStream.java:
##########
@@ -1647,16 +1661,8 @@ public synchronized boolean seekToNewSource(long
targetPos)
if (currentNode == null) {
return seekToBlockSource(targetPos);
}
- boolean markedDead = dfsClient.isDeadNode(this, currentNode);
- addToLocalDeadNodes(currentNode);
Review Comment:
Thanks for your review, seekToNewSource is a synchronous method, so the
method is atomic; and the method turns out to just add the current node to the
local deadnodes; so I think it will not affect the dead node detector.
> seekToNewSource uses ignoredNodes to get a new node other than the current
> node.
> --------------------------------------------------------------------------------
>
> Key: HDFS-17320
> URL: https://issues.apache.org/jira/browse/HDFS-17320
> Project: Hadoop HDFS
> Issue Type: Improvement
> Reporter: Jian Zhang
> Assignee: Jian Zhang
> Priority: Minor
> Labels: pull-request-available
> Attachments: HDFS-17320.001.patch
>
>
> Currently, when using the DFSInputStream#seekToNewSource() method to obtain a
> new datanode, the current datanode will be marked as deadnode first, thus
> preventing the new datanode from being equal to the current datanode.
> If the current datanode is indeed a dead node, after obtaining the new
> datanode, there is no need to mark the current datanode as a non-dead node;
> but if the current node is not a dead node, after obtaining the new datanode,
> the current node needs to be marked as Non-dead nodes (removed from the
> deadnodes collection), the current implementation method has no problem with
> its function, but it is very inelegant.
> Currently, when selecting a new datanode
> (DFSInputStream#getBestNodeDNAddrPair), you can filter out unnecessary
> datanodes through the parameter ignoredNodes. Therefore, we only need to pass
> the current datanode into ignoredNodes to elegantly implement the function of
> the seekToNewSource method.
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