[SPARK-7819] Isolated Hive Client Loader appears to cause Native Library libMapRClient.4.0.2-mapr.so already loaded in another classloader error

• Type: Bug
• Status: Resolved
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 1.4.0
• Fix Version/s: 1.4.0
• Component/s: SQL
• Target Version/s: 1.4.1, 1.5.0
• Assignee: Yin Huai
• Reporter: Fi
• Created: 22/May/15 05:01
• Updated: 28/Jul/15 05:12
• Resolved: 12/Jun/15 22:17

Description

In reference to the pull request: https://github.com/apache/spark/pull/5876

I have been running the Spark 1.3 branch for some time with no major hiccups, and recently switched to the Spark 1.4 branch.

I build my spark distribution with the following build command:

make-distribution.sh --tgz --skip-java-test --with-tachyon -Phive -Phive-0.13.1 -Pmapr4 -Pspark-ganglia-lgpl -Pkinesis-asl -Phive-thriftserver

When running a python script containing a series of smoke tests I use to validate the build, I encountered an error under the following conditions:

• start a spark context
• start a hive context
• run any hive query
• stop the spark context
• start a second spark context
• run any hive query
  • ERROR

From what I can tell, the Isolated Class Loader is hitting a MapR class that is loading its native library (presumedly as part of a static initializer).

Unfortunately, the JVM prohibits this the second time around.

I would think that shutting down the SparkContext would clear out any vestigials of the JVM, so I'm surprised that this would even be a problem.

Note: all other smoke tests we are running passes fine.

I will attach the stacktrace and a python script reproducing the issue (at least for my environment and build).

Issue Links

• is duplicated by: SPARK-9275 IsolatedClientLoader could not load shared JNI libraries