Revert "[SPARK-7157][SQL] add sampleBy to DataFrame"

This reverts commit 0401cbaa8ee51c71f43604f338b65022a479da0a.

The new test case on Jenkins is failing.

2 files changed, 2 insertions, 34 deletions

diff --git a/sql/core/src/main/scala/org/apache/spark/sql/DataFrameStatFunctions.scala b/sql/core/src/main/scala/org/apache/spark/sql/DataFrameStatFunctions.scala
index 955d28771b..edb9ed7bba 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/DataFrameStatFunctions.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/DataFrameStatFunctions.scala
@@ -17,8 +17,6 @@
 
 package org.apache.spark.sql
 
-import java.util.UUID
-
 import org.apache.spark.annotation.Experimental
 import org.apache.spark.sql.execution.stat._
 
@@ -165,26 +163,4 @@ final class DataFrameStatFunctions private[sql](df: DataFrame) {
   def freqItems(cols: Seq[String]): DataFrame = {
     FrequentItems.singlePassFreqItems(df, cols, 0.01)
   }
-
-  /**
-   * Returns a stratified sample without replacement based on the fraction given on each stratum.
-   * @param col column that defines strata
-   * @param fractions sampling fraction for each stratum. If a stratum is not specified, we treat
-   *                  its fraction as zero.
-   * @param seed random seed
-   * @return a new [[DataFrame]] that represents the stratified sample
-   *
-   * @since 1.5.0
-   */
-  def sampleBy(col: String, fractions: Map[Any, Double], seed: Long): DataFrame = {
-    require(fractions.values.forall(p => p >= 0.0 && p <= 1.0),
-      s"Fractions must be in [0, 1], but got $fractions.")
-    import org.apache.spark.sql.functions.rand
-    val c = Column(col)
-    val r = rand(seed).as("rand_" + UUID.randomUUID().toString.take(8))
-    val expr = fractions.toSeq.map { case (k, v) =>
-      (c === k) && (r < v)
-    }.reduce(_ || _) || false
-    df.filter(expr)
-  }
 }
diff --git a/sql/core/src/test/scala/org/apache/spark/sql/DataFrameStatSuite.scala b/sql/core/src/test/scala/org/apache/spark/sql/DataFrameStatSuite.scala
index 3dd4688912..0d3ff899da 100644
--- a/sql/core/src/test/scala/org/apache/spark/sql/DataFrameStatSuite.scala
+++ b/sql/core/src/test/scala/org/apache/spark/sql/DataFrameStatSuite.scala
@@ -19,9 +19,9 @@ package org.apache.spark.sql
 
 import org.scalatest.Matchers._
 
-import org.apache.spark.sql.functions.col
+import org.apache.spark.SparkFunSuite
 
-class DataFrameStatSuite extends QueryTest {
+class DataFrameStatSuite extends SparkFunSuite  {
 
   private val sqlCtx = org.apache.spark.sql.test.TestSQLContext
   import sqlCtx.implicits._
@@ -98,12 +98,4 @@ class DataFrameStatSuite extends QueryTest {
     val items2 = singleColResults.collect().head
     items2.getSeq[Double](0) should contain (-1.0)
   }
-
-  test("sampleBy") {
-    val df = sqlCtx.range(0, 100).select((col("id") % 3).as("key"))
-    val sampled = df.stat.sampleBy("key", Map(0 -> 0.1, 1 -> 0.2), 0L)
-    checkAnswer(
-      sampled.groupBy("key").count().orderBy("key"),
-      Seq(Row(0, 4), Row(1, 9)))
-  }
 }