Re: Spark SQL "lateral view explode" doesn't work, and unable to save array types to Parquet

Cheng Lian Fri, 27 Mar 2015 04:21:08 -0700

This should be a bug in the Explode.eval(), which always assumes theunderlying SQL array is represented by a Scala Seq. Would you mind toopen a JIRA ticket for this? Thanks!


Cheng


On 3/27/15 7:00 PM, Jon Chase wrote:

Spark 1.3.0

Two issues:
a) I'm unable to get a "lateral view explode" query to work on anarray type
b) I'm unable to save an array type to a Parquet file

I keep running into this:
java.lang.ClassCastException: [I cannot be cast toscala.collection.Seq
Here's a stack trace from the explode issue:

root
 |-- col1: string (nullable = false)
 |-- col2s: array (nullable = true)
 |    |-- element: integer (containsNull = true)
ERROR org.apache.spark.executor.Executor Exception in task 7.0 instage 1.0 (TID 15)
java.lang.ClassCastException: [I cannot be cast to scala.collection.Seq
atorg.apache.spark.sql.catalyst.expressions.Explode.eval(generators.scala:125)~[spark-catalyst_2.10-1.3.0.jar:1.3.0]atorg.apache.spark.sql.execution.Generate$$anonfun$2$$anonfun$apply$1.apply(Generate.scala:70)~[spark-sql_2.10-1.3.0.jar:1.3.0]atorg.apache.spark.sql.execution.Generate$$anonfun$2$$anonfun$apply$1.apply(Generate.scala:69)~[spark-sql_2.10-1.3.0.jar:1.3.0]at scala.collection.Iterator$$anon$13.hasNext(Iterator.scala:371)~[scala-library-2.10.4.jar:na]at scala.collection.Iterator$$anon$11.hasNext(Iterator.scala:327)~[scala-library-2.10.4.jar:na]at scala.collection.Iterator$$anon$11.hasNext(Iterator.scala:327)~[scala-library-2.10.4.jar:na]at scala.collection.Iterator$$anon$11.hasNext(Iterator.scala:327)~[scala-library-2.10.4.jar:na]at scala.collection.Iterator$class.foreach(Iterator.scala:727)~[scala-library-2.10.4.jar:na]at scala.collection.AbstractIterator.foreach(Iterator.scala:1157)~[scala-library-2.10.4.jar:na]atscala.collection.generic.Growable$class.$plus$plus$eq(Growable.scala:48)~[scala-library-2.10.4.jar:na]atscala.collection.mutable.ArrayBuffer.$plus$plus$eq(ArrayBuffer.scala:103)~[scala-library-2.10.4.jar:na]atscala.collection.mutable.ArrayBuffer.$plus$plus$eq(ArrayBuffer.scala:47)~[scala-library-2.10.4.jar:na]at scala.collection.TraversableOnce$class.to<http://class.to>(TraversableOnce.scala:273)~[scala-library-2.10.4.jar:na]at scala.collection.AbstractIterator.to<http://scala.collection.AbstractIterator.to>(Iterator.scala:1157)~[scala-library-2.10.4.jar:na]atscala.collection.TraversableOnce$class.toBuffer(TraversableOnce.scala:265)~[scala-library-2.10.4.jar:na]at scala.collection.AbstractIterator.toBuffer(Iterator.scala:1157)~[scala-library-2.10.4.jar:na]atscala.collection.TraversableOnce$class.toArray(TraversableOnce.scala:252)~[scala-library-2.10.4.jar:na]at scala.collection.AbstractIterator.toArray(Iterator.scala:1157)~[scala-library-2.10.4.jar:na]at org.apache.spark.rdd.RDD$$anonfun$17.apply(RDD.scala:813)~[spark-core_2.10-1.3.0.jar:1.3.0]at org.apache.spark.rdd.RDD$$anonfun$17.apply(RDD.scala:813)~[spark-core_2.10-1.3.0.jar:1.3.0]atorg.apache.spark.SparkContext$$anonfun$runJob$5.apply(SparkContext.scala:1497)~[spark-core_2.10-1.3.0.jar:1.3.0]atorg.apache.spark.SparkContext$$anonfun$runJob$5.apply(SparkContext.scala:1497)~[spark-core_2.10-1.3.0.jar:1.3.0]at org.apache.spark.scheduler.ResultTask.runTask(ResultTask.scala:61)~[spark-core_2.10-1.3.0.jar:1.3.0]at org.apache.spark.scheduler.Task.run(Task.scala:64)~[spark-core_2.10-1.3.0.jar:1.3.0]atorg.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:203)~[spark-core_2.10-1.3.0.jar:1.3.0]atjava.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)[na:1.8.0_31]atjava.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)[na:1.8.0_31]
at java.lang.Thread.run(Thread.java:745) [na:1.8.0_31]
WARN o.a.spark.scheduler.TaskSetManager Lost task 7.0 in stage 1.0(TID 15, localhost): java.lang.ClassCastException: [I cannot be castto scala.collection.Seqatorg.apache.spark.sql.catalyst.expressions.Explode.eval(generators.scala:125)atorg.apache.spark.sql.execution.Generate$$anonfun$2$$anonfun$apply$1.apply(Generate.scala:70)atorg.apache.spark.sql.execution.Generate$$anonfun$2$$anonfun$apply$1.apply(Generate.scala:69)
at scala.collection.Iterator$$anon$13.hasNext(Iterator.scala:371)
at scala.collection.Iterator$$anon$11.hasNext(Iterator.scala:327)
at scala.collection.Iterator$$anon$11.hasNext(Iterator.scala:327)
at scala.collection.Iterator$$anon$11.hasNext(Iterator.scala:327)
at scala.collection.Iterator$class.foreach(Iterator.scala:727)
at scala.collection.AbstractIterator.foreach(Iterator.scala:1157)
atscala.collection.generic.Growable$class.$plus$plus$eq(Growable.scala:48)atscala.collection.mutable.ArrayBuffer.$plus$plus$eq(ArrayBuffer.scala:103)atscala.collection.mutable.ArrayBuffer.$plus$plus$eq(ArrayBuffer.scala:47)at scala.collection.TraversableOnce$class.to<http://class.to>(TraversableOnce.scala:273)at scala.collection.AbstractIterator.to<http://scala.collection.AbstractIterator.to>(Iterator.scala:1157)atscala.collection.TraversableOnce$class.toBuffer(TraversableOnce.scala:265)
at scala.collection.AbstractIterator.toBuffer(Iterator.scala:1157)
atscala.collection.TraversableOnce$class.toArray(TraversableOnce.scala:252)
at scala.collection.AbstractIterator.toArray(Iterator.scala:1157)
at org.apache.spark.rdd.RDD$$anonfun$17.apply(RDD.scala:813)
at org.apache.spark.rdd.RDD$$anonfun$17.apply(RDD.scala:813)
atorg.apache.spark.SparkContext$$anonfun$runJob$5.apply(SparkContext.scala:1497)atorg.apache.spark.SparkContext$$anonfun$runJob$5.apply(SparkContext.scala:1497)
at org.apache.spark.scheduler.ResultTask.runTask(ResultTask.scala:61)
at org.apache.spark.scheduler.Task.run(Task.scala:64)
at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:203)
atjava.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)atjava.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)



Maybe I'm defining the schema incorrectly?



This test demonstrates both issues:

    @Rule
    public TemporaryFolder tmp = new TemporaryFolder();

    @Test
    public void testPercentileWithExplode() throws Exception {
        StructType schema = DataTypes.createStructType(Lists.newArrayList(
DataTypes.createStructField("col1",DataTypes.StringType, false),DataTypes.createStructField("col2s",DataTypes.createArrayType(DataTypes.IntegerType, true), true)
        ));

        JavaRDD<Row> rowRDD = sc.parallelize(Lists.newArrayList(
                RowFactory.create("test", new int[]{1, 2, 3})
        ));

        DataFrame df = sql.createDataFrame(rowRDD, schema);
        df.registerTempTable("df");
        df.printSchema();

        List<int[]> ints = sql.sql("select col2s from df").javaRDD()
                              .map(row -> (int[]) row.get(0)).collect();
        assertEquals(1, ints.size());
        assertArrayEquals(new int[]{1, 2, 3}, ints.get(0));
// fails: lateral view explode does not work:java.lang.ClassCastException: [I cannot be cast to scala.collection.SeqList<Integer> explodedInts = sql.sql("select col2 from dflateral view explode(col2s) splode as col2").javaRDD().map(row ->row.getInt(0)).collect();
        assertEquals(3, explodedInts.size());
        assertEquals(Lists.newArrayList(1, 2, 3), explodedInts);
// fails: java.lang.ClassCastException: [I cannot be cast toscala.collection.Seq
df.saveAsParquetFile(tmp.getRoot().getAbsolutePath() + "/parquet");
DataFrame loadedDf = sql.load(tmp.getRoot().getAbsolutePath()+ "/parquet");
        loadedDf.registerTempTable("loadedDf");
List<int[]> moreInts = sql.sql("select col2s fromloadedDf").javaRDD().map(row -> (int[])row.get(0)).collect();
        assertEquals(1, moreInts.size());
        assertArrayEquals(new int[]{1, 2, 3}, moreInts.get(0));
    }

Re: Spark SQL "lateral view explode" doesn't work, and unable to save array types to Parquet

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