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https://issues.apache.org/jira/browse/HADOOP-6889?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12893863#action_12893863
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Todd Lipcon commented on HADOOP-6889:
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Hi Hairong. I agree that it should be per-proxy, and also that this is useful.
We have a customer who has occasionally run into this with problematic "stuck"
datanodes blocking pipeline recovery indefinitely (at least until ops notices
the hung machine and powers it down, causing TCP connection to drop).
> Make RPC to have an option to timeout
> -------------------------------------
>
> Key: HADOOP-6889
> URL: https://issues.apache.org/jira/browse/HADOOP-6889
> Project: Hadoop Common
> Issue Type: New Feature
> Components: ipc
> Affects Versions: 0.22.0
> Reporter: Hairong Kuang
> Assignee: Hairong Kuang
> Fix For: 0.22.0, 0.20-append
>
>
> Currently Hadoop RPC does not timeout when the RPC server is alive. What it
> currently does is that a RPC client sends a ping to the server whenever a
> socket timeout happens. If the server is still alive, it continues to wait
> instead of throwing a SocketTimeoutException. This is to avoid a client to
> retry when a server is busy and thus making the server even busier. This
> works great if the RPC server is NameNode.
> But Hadoop RPC is also used for some of client to DataNode communications,
> for example, for getting a replica's length. When a client comes across a
> problematic DataNode, it gets stuck and can not switch to a different
> DataNode. In this case, it would be better that the client receives a timeout
> exception.
> I plan to add a new configuration ipc.client.max.pings that specifies the max
> number of pings that a client could try. If a response can not be received
> after the specified max number of pings, a SocketTimeoutException is thrown.
> If this configuration property is not set, a client maintains the current
> semantics, waiting forever.
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