[ZEPPELIN-2828] unhandled NullPointerException in PostgreSqlInterpreter when unable to connect

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 0.7.2
• Component/s: Interpreters

Environment

AWS EMR

• Assignee: Unassigned
• Reporter: Richard Xin
• Created: 04/Aug/17 00:29
• Updated: 04/Aug/17 00:33

Description

Steps to reproduce:
1. add postges interpreter via Interpreter UI
2. use "jdbc:postgresql://[db_host]:5432/" as postgresql.url where the default value was "jdbc:postgresql://localhost:5432/"
3. create a new notebook:
%postgresql (or %psql)
select * from test.batch_report;

got NPE, and here is what in the log:

INFO [2017-08-03 20:22:53,610] (

{pool-2-thread-2} SchedulerFactory.java[jobStarted]:131) - Job paragraph_1501783535283_1713771734 started by scheduler org.apache.zeppelin.interpreter.remote.RemoteInterpretershared_session392982422
INFO [2017-08-03 20:22:53,611] ({pool-2-thread-2}

Paragraph.java[jobRun]:362) - run paragraph 20170803-180535_552293631 using psql org.apache.zeppelin.interpreter.LazyOpenInterpreter@144aa9ed
INFO [2017-08-03 20:22:53,620] (

{pool-2-thread-2} RemoteInterpreterManagedProcess.java[start]:126) - Run interpreter process [/usr/lib/zeppelin/bin/interpreter.sh, -d, /usr/lib/zeppelin/interpreter/postgresql, -p, 42610, -l, /usr/lib/zeppelin/local-repo/2CPQEJPGC]
INFO [2017-08-03 20:22:54,190] ({pool-2-thread-2}

RemoteInterpreter.java[init]:221) - Create remote interpreter org.apache.zeppelin.postgresql.PostgreSqlInterpreter
INFO [2017-08-03 20:22:54,370] (

{pool-2-thread-2} RemoteInterpreter.java[pushAngularObjectRegistryToRemote]:551) - Push local angular object registry from ZeppelinServer to remote interpreter group 2CPQEJPGC:shared_process
WARN [2017-08-03 20:22:54,606] ({pool-2-thread-2}

NotebookServer.java[afterStatusChange]:2058) - Job 20170803-180535_552293631 is finished, status: ERROR, exception: null, result: %text java.lang.NullPointerException
at org.apache.zeppelin.postgresql.PostgreSqlInterpreter.executeSql(PostgreSqlInterpreter.java:202)
at org.apache.zeppelin.postgresql.PostgreSqlInterpreter.interpret(PostgreSqlInterpreter.java:289)
at org.apache.zeppelin.interpreter.LazyOpenInterpreter.interpret(LazyOpenInterpreter.java:97)
at org.apache.zeppelin.interpreter.remote.RemoteInterpreterServer$InterpretJob.jobRun(RemoteInterpreterServer.java:498)
at org.apache.zeppelin.scheduler.Job.run(Job.java:175)
at org.apache.zeppelin.scheduler.FIFOScheduler$1.run(FIFOScheduler.java:139)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)

INFO [2017-08-03 20:22:54,673] (

{pool-2-thread-2}

SchedulerFactory.java[jobFinished]:137) - Job paragraph_1501783535283_1713771734 finished by scheduler org.apache.zeppelin.interpreter.remote.RemoteInterpretershared_session392982422

I later worked around NPE by adding database name as part of the postgresql.url.

I believe this NPE exception is better to be handled and emit more user-friendly error message.