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https://issues.apache.org/jira/browse/FLINK-16030?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17036217#comment-17036217
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Piotr Nowojski commented on FLINK-16030:
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So the real world scenario is that the network connection between the Task
Managers and Job Manager is working fine, heart beats are going through, there
were no other exceptions? And just a single (or bunch of) connection between
some two Task Managers is not working properly?
I'm trying to understand the severity/impact of this issue and whether we can
solve it in some other way. As I wrote above, adding a heartbeat between Task
Managers could open different can of worms, like it wouldn't probably be stable
for any job using {{BoundedBlockingSubpartition}} (while I'm not entirely sure
if {{PipelinedSubpartition}} is 100% non blocking).
> Add heartbeat between netty server and client to detect long connection alive
> -----------------------------------------------------------------------------
>
> Key: FLINK-16030
> URL: https://issues.apache.org/jira/browse/FLINK-16030
> Project: Flink
> Issue Type: Improvement
> Components: Runtime / Network
> Affects Versions: 1.7.2, 1.8.3, 1.9.2, 1.10.0
> Reporter: begginghard
> Priority: Major
>
> As reported on [the user mailing
> list|https://lists.apache.org/[email protected]:lte=1M:Encountered%20error%20while%20consuming%20partitions]
> Network can fail in many ways, sometimes pretty subtle (e.g. high ratio
> packet loss).
> When the long tcp connection between netty client and server is lost, the
> server would failed to send response to the client, then shut down the
> channel. At the same time, the netty client does not know that the connection
> has been disconnected, so it has been waiting for two hours.
> To detect the long tcp connection alive on netty client and server, we should
> have two ways: tcp keepalive and heartbeat.
>
> The tcp keepalive is 2 hours by default. When the long tcp connection dead,
> you continue to wait for 2 hours, the netty client will trigger exception and
> enter failover recovery.
> If you want to detect quickly, netty provides IdleStateHandler which it use
> ping-pang mechanism. If netty client sends continuously n ping message and
> receives no one pang message, then trigger exception.
>
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