Major Description
Accessing null elements in an array field fails when tungsten is enabled.
It works in Spark 1.3.1, and in Spark > 1.5 with Tungsten disabled.
Example:
// Array of String case class AS( as: Seq[String] ) val dfAS = sc.parallelize( Seq( AS ( Seq("a",null,"b") ) ) ).toDF dfAS.registerTempTable("T_AS") for (i <- 0 to 2) { println(i + " = " + sqlContext.sql(s"select as[$i] from T_AS").collect.mkString(","))}
With Tungsten disabled:
0 = [a]
1 = [null]
2 = [b]
With Tungsten enabled:
0 = [a]
15/12/22 09:32:50 ERROR Executor: Exception in task 7.0 in stage 1.0 (TID 15)
java.lang.NullPointerException
at org.apache.spark.sql.catalyst.expressions.UnsafeRowWriters$UTF8StringWriter.getSize(UnsafeRowWriters.java:90)
at org.apache.spark.sql.catalyst.expressions.GeneratedClass$SpecificUnsafeProjection.apply(Unknown Source)
at org.apache.spark.sql.execution.TungstenProject$$anonfun$3$$anonfun$apply$3.apply(basicOperators.scala:90)
at org.apache.spark.sql.execution.TungstenProject$$anonfun$3$$anonfun$apply$3.apply(basicOperators.scala:88)
at scala.collection.Iterator$$anon$11.next(Iterator.scala:328)
at scala.collection.Iterator$$anon$11.next(Iterator.scala:328)
at scala.collection.Iterator$class.foreach(Iterator.scala:727)
at scala.collection.AbstractIterator.foreach(Iterator.scala:1157)
------------------------------
More examples below.
The following code works in Spark 1.3.1, and in Spark > 1.5 with Tungsten disabled:
// Array of String case class AS( as: Seq[String] ) val dfAS = sc.parallelize( Seq( AS ( Seq("a",null,"b") ) ) ).toDF dfAS.registerTempTable("T_AS") for (i <- 0 to 10) { println(i + " = " + sqlContext.sql(s"select as[$i] from T_AS").collect.mkString(","))} // Array of Int case class AI( ai: Seq[Option[Int]] ) val dfAI = sc.parallelize( Seq( AI ( Seq(Some(1),None,Some(2) ) ) ) ).toDF dfAI.registerTempTable("T_AI") for (i <- 0 to 10) { println(i + " = " + sqlContext.sql(s"select ai[$i] from T_AI").collect.mkString(","))} // Array of struct[Int,String] case class B(x: Option[Int], y: String) case class A( b: Seq[B] ) val df1 = sc.parallelize( Seq( A ( Seq( B(Some(1),"a"),B(Some(2),"b"), B(None, "c"), B(Some(4),null), B(None,null), null ) ) ) ).toDF df1.registerTempTable("T1") val df2 = sc.parallelize( Seq( A ( Seq( B(Some(1),"a"),B(Some(2),"b"), B(None, "c"), B(Some(4),null), B(None,null), null ) ), A(null) ) ).toDF df2.registerTempTable("T2") for (i <- 0 to 10) { println(i + " = " + sqlContext.sql(s"select b[$i].x, b[$i].y from T1").collect.mkString(","))} for (i <- 0 to 10) { println(i + " = " + sqlContext.sql(s"select b[$i].x, b[$i].y from T2").collect.mkString(","))} // Struct[Int,String] case class C(b: B) val df3 = sc.parallelize( Seq( C ( B(Some(1),"test") ), C(null) ) ).toDF df3.registerTempTable("T3") sqlContext.sql("select b.x, b.y from T3").collect
With Tungsten enabled, it reaches NullPointerException.
