[
https://issues.apache.org/jira/browse/HDFS-14997?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17181643#comment-17181643
]
Xiaoqiao He commented on HDFS-14997:
------------------------------------
Thanks [~Captainhzy] for your comments. This improvement try to process some
high cost cmds async, and avoid to block the core flow of BPServiceActor, such
as `DNA_INVALIDATE`.
As for your concerns, It could be not issue IMO, because
`updateActorStatesFromHeartbeat` is very light operation, no need to async.
Another side, we need to update namenode state at real time to avoid to execute
some cmds from Standby. Hope it could answer your questions. Thanks.
> BPServiceActor processes commands from NameNode asynchronously
> --------------------------------------------------------------
>
> Key: HDFS-14997
> URL: https://issues.apache.org/jira/browse/HDFS-14997
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: datanode
> Reporter: Xiaoqiao He
> Assignee: Xiaoqiao He
> Priority: Major
> Fix For: 3.3.0
>
> Attachments: HDFS-14997.001.patch, HDFS-14997.002.patch,
> HDFS-14997.003.patch, HDFS-14997.004.patch, HDFS-14997.005.patch,
> HDFS-14997.addendum.patch, image-2019-12-26-16-15-44-814.png
>
>
> There are two core functions, report(#sendHeartbeat, #blockReport,
> #cacheReport) and #processCommand in #BPServiceActor main process flow. If
> processCommand cost long time it will block send report flow. Meanwhile
> processCommand could cost long time(over 1000s the worst case I meet) when IO
> load of DataNode is very high. Since some IO operations are under
> #datasetLock, So it has to wait to acquire #datasetLock long time when
> process some of commands(such as #DNA_INVALIDATE). In such case, #heartbeat
> will not send to NameNode in-time, and trigger other disasters.
> I propose to improve #processCommand asynchronously and not block
> #BPServiceActor to send heartbeat back to NameNode when meet high IO load.
> Notes:
> 1. Lifeline could be one effective solution, however some old branches are
> not support this feature.
> 2. IO operations under #datasetLock is another issue, I think we should solve
> it at another JIRA.
--
This message was sent by Atlassian Jira
(v8.3.4#803005)
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
