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https://issues.apache.org/jira/browse/HADOOP-6889?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13069379#comment-13069379
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Uma Maheswara Rao G commented on HADOOP-6889:
---------------------------------------------
Hi John,
I have seen waitForProxy is passing 0 as rpcTimeOut. It is hardcoded value.
{code}
return waitForProtocolProxy(protocol, clientVersion, addr, conf, 0,
connTimeout);
{code}
If user wants to control this value then , how can he configure?
Here we have a situation, where clients are waiting for long time.HDFS-1880.
I thought, HADOOP-6889 can solve that problem. But how this can be controlled
by the user in Hadoop (looks no configuration parameters available).
{quote}
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.
{quote}
We have choosen this implementation for our cluster.
I am just checking , whether i can use rpcTimeOut itself to control. ( since
this change already committed).
Can you please clarify more?
Can you just check HDFS-1880.
@Hairong
{quote}
I thought about introducing a configuration parameter. But clients or DataNodes
want to have timeout for RPCs to DataNodes but no timeout for RPCs to
NameNodes. Adding a rpcTimeout parameter makes this easy.
{quote}
I think considering HA, clients and NameNode also requires some timeout.
If Active goes down, then clients should not wait in timeouts right?
> 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: John George
> Fix For: 0.20-append, 0.20.205.0, 0.22.0
>
> Attachments: HADOOP-6889-for20.patch, HADOOP-6889.patch,
> ipcTimeout.patch, ipcTimeout1.patch, ipcTimeout2.patch
>
>
> 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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