Debug Beeline Client for Hive

Just a note how to enable debug mode in beeline (or any other) Hive client.

To enable remote debugging, we need to pass "-Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=n,address=5005" arguments to JVM.

Tricky part is to find the place where JVM is being executed. It's file $HADOOP_HOME/hive-client/bin/ext/beeline.sh - in Hortonworks (HDP) installation it will be /usr/hdp/current/hive-client/bin/ext/beeline.sh

On the line
exec $HADOOP jar ${beelineJarPath} $CLASS $HIVE_OPTS "$@"

but -Xdebug option should be placed to HADOOP_CLIENT_OPTS variable:

export HADOOP_CLIENT_OPTS="$HADOOP_CLIENT_OPTS -Dlog4j.configuration=beeline-log4j.properties -Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=n,address=5005"
 

-Xdebug - enables remote debugging
-Xrunjdwp - sets configuration properties, where
server - start server or try to connect to debugger (usually server=y to do remote debug via Idea)
suspend - freeze start of program and wait until debugger connects to it
address -  port of server you will connect to

Now if you just start # beeline
you'll see that debug server started on port 5005, and you can connect to it via Idea (or whatever).