[SPARK-18022] java.lang.NullPointerException instead of real exception when saving DF to MySQL

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 2.0.1
• Fix Version/s: 2.0.2, 2.1.0
• Component/s: SQL
• Assignee: Sean R. Owen
• Reporter: Maciej Bryński
• Created: 20/Oct/16 06:06
• Updated: 26/Oct/16 12:23
• Resolved: 26/Oct/16 12:20

Description

Hi,
I have found following issue.
When there is an exception while saving dataframe to MySQL I'm unable to get it.
Instead of I'm getting following stacktrace.

16/10/20 06:00:35 WARN TaskSetManager: Lost task 56.0 in stage 10.0 (TID 3753, dwh-hn28.adpilot.co): java.lang.NullPointerException: Cannot suppress a null exception.
        at java.lang.Throwable.addSuppressed(Throwable.java:1046)
        at org.apache.spark.sql.execution.datasources.jdbc.JdbcUtils$.savePartition(JdbcUtils.scala:256)
        at org.apache.spark.sql.execution.datasources.jdbc.JdbcUtils$$anonfun$saveTable$1.apply(JdbcUtils.scala:314)
        at org.apache.spark.sql.execution.datasources.jdbc.JdbcUtils$$anonfun$saveTable$1.apply(JdbcUtils.scala:313)
        at org.apache.spark.rdd.RDD$$anonfun$foreachPartition$1$$anonfun$apply$28.apply(RDD.scala:902)
        at org.apache.spark.rdd.RDD$$anonfun$foreachPartition$1$$anonfun$apply$28.apply(RDD.scala:902)
        at org.apache.spark.SparkContext$$anonfun$runJob$5.apply(SparkContext.scala:1916)
        at org.apache.spark.SparkContext$$anonfun$runJob$5.apply(SparkContext.scala:1916)
        at org.apache.spark.scheduler.ResultTask.runTask(ResultTask.scala:70)
        at org.apache.spark.scheduler.Task.run(Task.scala:86)
        at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:274)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
        at java.lang.Thread.run(Thread.java:745)

The real exception could be for example duplicate on primary key etc.

With this it's very difficult to debugging apps.

Issue Links

• links to: [Github] Pull Request #15599 (srowen)