[jira] [Created] (IMPALA-6705) TotalNetworkSendTime in query profile is misleading

["Michael Ho (JIRA)" <ji...@apache.org>]

Michael Ho created IMPALA-6705:
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             Summary: TotalNetworkSendTime in query profile is misleading
                 Key: IMPALA-6705
                 URL: https://issues.apache.org/jira/browse/IMPALA-6705
             Project: IMPALA
          Issue Type: Bug
          Components: Distributed Exec
    Affects Versions: Impala 2.11.0, Impala 2.10.0, Impala 2.9.0, Impala 2.8.0, Impala 2.7.0, Impala 2.6.0, Impala 2.4.0, Impala 2.5.0, Impala 2.12.0
            Reporter: Michael Ho


{{TotalNetworkSendTime}} is actually measuring the time which a fragment instance execution thread spent waiting for the completion of previous RPC. This is a combination of:
 - network time of sending the RPC payload to the destination
 - processing and queuing time in the destination
 - network time of sending the RPC response to the originating node

The name of this metric itself is misleading because it gives the impression that it's the time spent sending the RPC payload to the destination so a query profile with a high {{TotalNetworkSendTime}} may easily mislead a user into concluding that there is something wrong with the network. In reality, the receiving end could be overloaded and it's taking a huge amount of time to respond to an RPC.

For this metric to be useful, we need to have a breakdown of those 3 components above.



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