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https://issues.apache.org/jira/browse/FLINK-4021?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15420965#comment-15420965
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ASF GitHub Bot commented on FLINK-4021:
---------------------------------------
Github user uce commented on a diff in the pull request:
https://github.com/apache/flink/pull/2141#discussion_r74760105
--- Diff:
flink-runtime/src/main/java/org/apache/flink/runtime/io/network/netty/PartitionRequestClientHandler.java
---
@@ -292,7 +296,11 @@ else if (bufferListener.waitForBuffer(bufferProvider,
bufferOrEvent)) {
return false;
}
else if (bufferProvider.isDestroyed()) {
- return false;
--- End diff --
We usually have a white space between keywords like `if` or `else`:
```java
if (isStagedBuffer) {
return true;
} else {
return false;
}
```
In this case, you can simplify the return value to `return isStagedBuffer`.
Same for the other place where you use this.
> Problem of setting autoread for netty channel when more tasks sharing the
> same Tcp connection
> ---------------------------------------------------------------------------------------------
>
> Key: FLINK-4021
> URL: https://issues.apache.org/jira/browse/FLINK-4021
> Project: Flink
> Issue Type: Bug
> Components: Distributed Coordination
> Affects Versions: 1.0.2
> Reporter: Zhijiang Wang
> Assignee: Zhijiang Wang
>
> More than one task sharing the same Tcp connection for shuffling data.
> If the downstream task said as "A" has no available memory segment to read
> netty buffer from network, it will set autoread as false for the channel.
> When the task A is failed or has available segments again, the netty handler
> will be notified to process the staging buffers first, then reset autoread as
> true. But in some scenarios, the autoread will not be set as true any more.
> That is when processing staging buffers, first find the corresponding input
> channel for the buffer, if the task for that input channel is failed, the
> decodeMsg method in PartitionRequestClientHandler will return false, that
> means setting autoread as true will not be done anymore.
> In summary, if one task "A" sets the autoread as false because of no
> available segments, and resulting in some staging buffers. If another task
> "B" is failed by accident corresponding to one staging buffer. When task A
> trys to reset autoread as true, the process can not work because of task B
> failed.
> I have fixed this problem in our application by adding one boolean parameter
> in decodeBufferOrEvent method to distinguish whether this method is invoke by
> netty IO thread channel read or staged message handler task in
> PartitionRequestClientHandler.
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