ClassCastException when using SparkSQL Window function

[Isabelle Phan <nl...@gmail.com>]

Hello,

I have a simple session table, which tracks pages users visited with a
sessionId. I would like to apply a window function by sessionId, but am
hitting a type cast exception. I am using Spark 1.5.0.

Here is sample code:
scala> df.printSchema
root
 |-- sessionid: string (nullable = true)
 |-- ip: string (nullable = true)
 |-- user_id: string (nullable = true)
 |-- timestamp: string (nullable = true)
 |-- page: string (nullable = true)

scala> df.withColumn("num",
rowNumber.over(Window.partitionBy("sessionid"))).show(10)

Here is the error stacktrace:
Caused by: java.lang.ClassCastException:
org.apache.spark.unsafe.types.UTF8String cannot be cast to java.lang.Integer
    at scala.runtime.BoxesRunTime.unboxToInt(BoxesRunTime.java:106)
    at
org.apache.spark.sql.catalyst.expressions.BaseGenericInternalRow$class.getInt(rows.scala:40)
    at
org.apache.spark.sql.catalyst.expressions.GenericInternalRow.getInt(rows.scala:220)
    at
org.apache.spark.sql.catalyst.expressions.JoinedRow.getInt(JoinedRow.scala:82)
    at
org.apache.spark.sql.catalyst.expressions.BoundReference.eval(BoundAttribute.scala:45)
    at
org.apache.spark.sql.catalyst.expressions.Alias.eval(namedExpressions.scala:121)
    at
org.apache.spark.sql.catalyst.expressions.InterpretedMutableProjection.apply(Projection.scala:82)
    at
org.apache.spark.sql.catalyst.expressions.InterpretedMutableProjection.apply(Projection.scala:61)
    at
org.apache.spark.sql.execution.Window$$anonfun$8$$anon$1.next(Window.scala:330)
    at
org.apache.spark.sql.execution.Window$$anonfun$8$$anon$1.next(Window.scala:252)
    at scala.collection.Iterator$$anon$11.next(Iterator.scala:328)
    at scala.collection.Iterator$$anon$10.next(Iterator.scala:312)
    at scala.collection.Iterator$class.foreach(Iterator.scala:727)
    at scala.collection.AbstractIterator.foreach(Iterator.scala:1157)
    at
scala.collection.generic.Growable$class.$plus$plus$eq(Growable.scala:48)
    at
scala.collection.mutable.ArrayBuffer.$plus$plus$eq(ArrayBuffer.scala:103)
    at
scala.collection.mutable.ArrayBuffer.$plus$plus$eq(ArrayBuffer.scala:47)
    at scala.collection.TraversableOnce$class.to(TraversableOnce.scala:273)
    at scala.collection.AbstractIterator.to(Iterator.scala:1157)
    at
scala.collection.TraversableOnce$class.toBuffer(TraversableOnce.scala:265)
    at scala.collection.AbstractIterator.toBuffer(Iterator.scala:1157)
    at
scala.collection.TraversableOnce$class.toArray(TraversableOnce.scala:252)
    at scala.collection.AbstractIterator.toArray(Iterator.scala:1157)
    at
org.apache.spark.sql.execution.SparkPlan$$anonfun$5.apply(SparkPlan.scala:215)
    at
org.apache.spark.sql.execution.SparkPlan$$anonfun$5.apply(SparkPlan.scala:215)
    at
org.apache.spark.SparkContext$$anonfun$runJob$5.apply(SparkContext.scala:1850)
    at
org.apache.spark.SparkContext$$anonfun$runJob$5.apply(SparkContext.scala:1850)
    at org.apache.spark.scheduler.ResultTask.runTask(ResultTask.scala:66)
    at org.apache.spark.scheduler.Task.run(Task.scala:88)
    at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:214)
    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)

Has anyone encountered this problem before? Any pointers would be greatly
appreciated.


Thanks!

Isabelle