Github user yhuai commented on a diff in the pull request:
https://github.com/apache/spark/pull/9364#discussion_r43467544
--- Diff: sql/core/src/test/scala/org/apache/spark/sql/DataFrameSuite.scala
---
@@ -987,4 +992,116 @@ class DataFrameSuite extends QueryTest with
SharedSQLContext {
val df = (1 to 10).map(Tuple1.apply).toDF("i").as("src")
assert(df.select($"src.i".cast(StringType)).columns.head === "i")
}
+
+ /**
+ * Verifies that there is no Exchange between the Aggregations for `df`
+ */
+ private def verifyNonExchangingAgg(df: DataFrame) = {
+ var atFirstAgg: Boolean = false
+ df.queryExecution.executedPlan.foreach {
+ case agg: TungstenAggregate => {
+ atFirstAgg = !atFirstAgg
+ }
+ case _ => {
+ if (atFirstAgg) {
+ fail("Should not have operators between the two aggregations")
+ }
+ }
+ }
+ }
+
+ /**
+ * Verifies that there is an Exchange between the Aggregations for `df`
+ */
+ private def verifyExchangingAgg(df: DataFrame) = {
+ var atFirstAgg: Boolean = false
+ df.queryExecution.executedPlan.foreach {
+ case agg: TungstenAggregate => {
+ if (atFirstAgg) {
+ fail("Should not have back to back Aggregates")
+ }
+ atFirstAgg = true
+ }
+ case e: Exchange => atFirstAgg = false
+ case _ =>
+ }
+ }
+
+ test("distributeBy") {
+ val original = testData.repartition(1)
+ assert(original.rdd.partitions.length == 1)
+ val df = original.distributeBy(Column("key") :: Nil, 5)
+ assert(df.rdd.partitions.length == 5)
+ checkAnswer(original.select(), df.select())
+
+ val df2 = original.distributeBy(Column("key") :: Nil, 10)
+ assert(df2.rdd.partitions.length == 10)
+ checkAnswer(original.select(), df2.select())
+
+ // Group by the column we are distributed by. This should generate a
plan with no exchange
+ // between the aggregates
+ val df3 = testData.distributeBy(Column("key") ::
Nil).groupBy("key").count()
+ verifyNonExchangingAgg(df3)
+ verifyNonExchangingAgg(testData.distributeBy(Column("key") ::
Column("value") :: Nil)
+ .groupBy("key", "value").count())
+
+ // Grouping by just the first distributeBy expr, need to exchange.
+ verifyExchangingAgg(testData.distributeBy(Column("key") ::
Column("value") :: Nil)
+ .groupBy("key").count())
+
+ val data = sqlContext.sparkContext.parallelize(
+ (1 to 100).map(i => TestData2(i % 10, i))).toDF()
+
+ // Distribute and order by.
+ val df4 = data.distributeBy(Column("a") :: Nil).localSort($"b".desc)
+ // Walk each partition and verify that it is sorted descending and not
globally sorted.
+ df4.rdd.foreachPartition(p => {
+ var previousValue: Int = -1
+ var globallyOrdered: Boolean = true
+ p.foreach(r => {
+ val v: Int = r.getInt(1)
+ if (previousValue != -1) {
+ if (previousValue < v) throw new SparkException("Partition is
not ordered.")
+ if (v + 1 != previousValue) globallyOrdered = false
+ }
+ previousValue = v
+ })
+ if (globallyOrdered) throw new SparkException("Partition should not
be globally ordered")
+ })
+
+ // Distribute and order by with multiple order bys
+ val df5 = data.distributeBy(Column("a") :: Nil, 2).localSort($"b".asc,
$"a".asc)
+ // Walk each partition and verify that it is sorted descending and not
globally sorted.
--- End diff --
descending => ascending
---
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