HDFS-17567. Return value of method RouterRpcClient#invokeSequential is not accurate.

[hfutatzhanghb]

Description of PR

Below code is the return value in method RouterRpcClient#invokeSequential.

// Return the first result, whether it is the value or not
@SuppressWarnings("unchecked") T ret = (T) firstResult;
return new RemoteResult<>(locations.get(0), ret); 

locations.get(0) is not accurate, because it may not be the remote location where ret was returned.

[hadoop-yetus]

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[ayushtkn]

didn't catch this... you need to extend a test for the case.
ret is the firstResult & locations.get(0) will be the first location where the method will be invoked, how it is wrong?

[hfutatzhanghb]

Member

@ayushtkn Sir, IIUC. suppose we have locations with three nameservices (ns1, ns2, ns3), when we invoke RPC targeting to ns1, it raised exception and we invoke RPC successfully targeting to ns2. This time the firstResult would be the return value of ns2.
So it does not match with locations.get(0).