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https://issues.apache.org/jira/browse/HIVE-24484?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17255634#comment-17255634
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David Mollitor commented on HIVE-24484:
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This effort is stuck on my part.

There are two big issues here:

Hive integration tests fire up Druid, Kafka, HDFS, LLAP, etc. all in the same 
JVM and their 3rd party dependencies are all over the place. Using a higher 
version of a dependency breaks one product, but using a lower version breaks 
the other. To make this work well, there probably needs to be a way to launch 
each service in their own JVM class loader. In lieu of that, I've been trying 
to move the ball closer to the goal post and getting dependencies closer 
together.
apache/druid#10683
HIVE-24542

In HDFS 3.3.0, Hadoop team introduced ProtobufRpcEngine2 in addition to 
ProtobufRpcEngine (sigh). Some of the Hive LLAP stuff is using this Hadoop 
Protobuf RPC engine (ProtobufRpcEngine). There's some static logic in the 
protocol engines that prohibits loading both RPC engines into the same JVM at 
the same time, I'm not sure why. HDFS was migrated to ProtobufRpcEngine2. So, 
again, in the integration tests, when the HDFS mini cluster is loaded, version 
2 of the RPC engine is loaded into the JVM. When LLAP is later loaded, it fails 
to start because version 1 cannot be registered at the same time.

> Upgrade Hadoop to 3.3.0
> -----------------------
>
>                 Key: HIVE-24484
>                 URL: https://issues.apache.org/jira/browse/HIVE-24484
>             Project: Hive
>          Issue Type: Improvement
>            Reporter: David Mollitor
>            Assignee: David Mollitor
>            Priority: Major
>              Labels: pull-request-available
>          Time Spent: 50m
>  Remaining Estimate: 0h
>




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