Merge branch 'master' of https://github.com/apache/spark into SPARK-1…

…712_new

core/src/main/scala/org/apache/spark/Partitioner.scala

@@ -156,3 +156,64 @@ class RangePartitioner[K : Ordering : ClassTag, V](
       false
   }
 }
+
+/**
+ * A [[org.apache.spark.Partitioner]] that partitions records into specified bounds
+ * Default value is 1000. Once all partitions have bounds elements, the partitioner
+ * allocates 1 element per partition so eventually the smaller partitions are at most
+ * off by 1 key compared to the larger partitions.
+ */
+class BoundaryPartitioner[K : Ordering : ClassTag, V](
+                                                    partitions: Int,
+                                                    @transient rdd: RDD[_ <: Product2[K,V]],
+                                                    private val boundary: Int = 1000)
+  extends Partitioner {
+
+  // this array keeps track of keys assigned to a partition
+  // counts[0] refers to # of keys in partition 0 and so on
+  private val counts: Array[Int] = {
+    new Array[Int](numPartitions)
+  }
+
+  def numPartitions = math.abs(partitions)
+
+  /*
+  * Ideally, this should've been calculated based on # partitions and total keys
+  * But we are not calling count on RDD here to avoid calling an action.
+   * User has the flexibility of calling count and passing in any appropriate boundary
+   */
+  def keysPerPartition = boundary
+
+  var currPartition = 0
+
+  /*
+  * Pick current partition for the key until we hit the bound for keys / partition,
+  * start allocating to next partition at that time.
+  *
+  * NOTE: In case where we have lets say 2000 keys and user says 3 partitions with 500
+  * passed in as boundary, the first 500 will goto P1, 501-1000 go to P2, 1001-1500 go to P3,
+  * after that, next keys go to one partition at a time. So 1501 goes to P1, 1502 goes to P2,
+  * 1503 goes to P3 and so on.
+   */
+  def getPartition(key: Any): Int = {
+    val partition = currPartition
+    counts(partition) = counts(partition) + 1
+    /*
+    * Since we are filling up a partition before moving to next one (this helps in maintaining
+    * order of keys, in certain cases, it is possible to end up with empty partitions, like
+    * 3 partitions, 500 keys / partition and if rdd has 700 keys, 1 partition will be entirely
+    * empty.
+     */
+    if(counts(currPartition) >= keysPerPartition)
+      currPartition = (currPartition + 1) % numPartitions
+    partition
+  }
+
+  override def equals(other: Any): Boolean = other match {
+    case r: BoundaryPartitioner[_,_] =>
+      (r.counts.sameElements(counts) && r.boundary == boundary
+        && r.currPartition == currPartition)
+    case _ =>
+      false
+  }
+}

core/src/main/scala/org/apache/spark/rdd/PairRDDFunctions.scala

@@ -217,7 +217,7 @@ class PairRDDFunctions[K, V](self: RDD[(K, V)])
    * Return approximate number of distinct values for each key in this RDD.
    * The accuracy of approximation can be controlled through the relative standard deviation
    * (relativeSD) parameter, which also controls the amount of memory used. Lower values result in
-   * more accurate counts but increase the memory footprint and vise versa. Uses the provided
+   * more accurate counts but increase the memory footprint and vice versa. Uses the provided
    * Partitioner to partition the output RDD.
    */
   def countApproxDistinctByKey(relativeSD: Double, partitioner: Partitioner): RDD[(K, Long)] = {
@@ -232,7 +232,7 @@ class PairRDDFunctions[K, V](self: RDD[(K, V)])
    * Return approximate number of distinct values for each key in this RDD.
    * The accuracy of approximation can be controlled through the relative standard deviation
    * (relativeSD) parameter, which also controls the amount of memory used. Lower values result in
-   * more accurate counts but increase the memory footprint and vise versa. HashPartitions the
+   * more accurate counts but increase the memory footprint and vice versa. HashPartitions the
    * output RDD into numPartitions.
    *
    */
@@ -244,7 +244,7 @@ class PairRDDFunctions[K, V](self: RDD[(K, V)])
    * Return approximate number of distinct values for each key this RDD.
    * The accuracy of approximation can be controlled through the relative standard deviation
    * (relativeSD) parameter, which also controls the amount of memory used. Lower values result in
-   * more accurate counts but increase the memory footprint and vise versa. The default value of
+   * more accurate counts but increase the memory footprint and vice versa. The default value of
    * relativeSD is 0.05. Hash-partitions the output RDD using the existing partitioner/parallelism
    * level.
    */

core/src/test/scala/org/apache/spark/PartitioningSuite.scala

@@ -66,6 +66,40 @@ class PartitioningSuite extends FunSuite with SharedSparkContext with PrivateMet
     assert(descendingP4 != p4)
   }
 
+  test("BoundaryPartitioner equality") {
+    // Make an RDD where all the elements are the same so that the partition range bounds
+    // are deterministically all the same.
+    val rdd = sc.parallelize(1.to(4000)).map(x => (x, x))
+
+    val p2 = new BoundaryPartitioner(2, rdd, 1000)
+    val p4 = new BoundaryPartitioner(4, rdd, 1000)
+    val anotherP4 = new BoundaryPartitioner(4, rdd)
+
+    assert(p2 === p2)
+    assert(p4 === p4)
+    assert(p2 != p4)
+    assert(p4 != p2)
+    assert(p4 === anotherP4)
+    assert(anotherP4 === p4)
+  }
+
+  test("BoundaryPartitioner getPartition") {
+    val rdd = sc.parallelize(1.to(2000)).map(x => (x, x))
+    val partitioner = new BoundaryPartitioner(4, rdd,  500)
+    1.to(2000).map { element => {
+      val partition = partitioner.getPartition(element)
+      if (element <= 500) {
+        assert(partition === 0)
+      } else if (element > 501 && element <= 1000) {
+        assert(partition === 1)
+      } else if (element > 1001 && element <= 1500) {
+        assert(partition === 2)
+      } else if (element > 1501 && element <= 2000) {
+        assert(partition === 3)
+      }
+    }}
+  }
+
   test("RangePartitioner getPartition") {
     val rdd = sc.parallelize(1.to(2000)).map(x => (x, x))
     // We have different behaviour of getPartition for partitions with less than 1000 and more than

core/src/test/scala/org/apache/spark/storage/DiskBlockManagerSuite.scala

@@ -52,7 +52,7 @@ class DiskBlockManagerSuite extends FunSuite with BeforeAndAfterEach with Before
     rootDir0.deleteOnExit()
     rootDir1 = Files.createTempDir()
     rootDir1.deleteOnExit()
-    rootDirs = rootDir0.getName + "," + rootDir1.getName
+    rootDirs = rootDir0.getAbsolutePath + "," + rootDir1.getAbsolutePath
     println("Created root dirs: " + rootDirs)
   }
 

python/pyspark/sql.py

@@ -28,7 +28,7 @@ class SQLContext:
     register L{SchemaRDD}s as tables, execute sql over tables, cache tables, and read parquet files.
     """
 
-    def __init__(self, sparkContext):
+    def __init__(self, sparkContext, sqlContext = None):
         """
         Create a new SQLContext.
 
@@ -58,10 +58,13 @@ def __init__(self, sparkContext):
         self._jvm = self._sc._jvm
         self._pythonToJavaMap = self._jvm.PythonRDD.pythonToJavaMap
 
+        if sqlContext:
+            self._scala_SQLContext = sqlContext
+
     @property
     def _ssql_ctx(self):
         """
-        Accessor for the JVM SparkSQL context.  Subclasses can overrite this property to provide
+        Accessor for the JVM SparkSQL context.  Subclasses can override this property to provide
         their own JVM Contexts.
         """
         if not hasattr(self, '_scala_SQLContext'):

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/SqlParser.scala

@@ -93,6 +93,7 @@ class SqlParser extends StandardTokenParsers with PackratParsers {
   protected val AND = Keyword("AND")
   protected val AS = Keyword("AS")
   protected val ASC = Keyword("ASC")
+  protected val APPROXIMATE = Keyword("APPROXIMATE")
   protected val AVG = Keyword("AVG")
   protected val BY = Keyword("BY")
   protected val CAST = Keyword("CAST")
@@ -318,6 +319,12 @@ class SqlParser extends StandardTokenParsers with PackratParsers {
     COUNT ~> "(" ~ "*" <~ ")" ^^ { case _ => Count(Literal(1)) } |
     COUNT ~> "(" ~ expression <~ ")" ^^ { case dist ~ exp => Count(exp) } |
     COUNT ~> "(" ~> DISTINCT ~> expression <~ ")" ^^ { case exp => CountDistinct(exp :: Nil) } |
+    APPROXIMATE ~> COUNT ~> "(" ~> DISTINCT ~> expression <~ ")" ^^ {
+      case exp => ApproxCountDistinct(exp)
+    } |
+    APPROXIMATE ~> "(" ~> floatLit ~ ")" ~ COUNT ~ "(" ~ DISTINCT ~ expression <~ ")" ^^ {
+      case s ~ _ ~ _ ~ _ ~ _ ~ e => ApproxCountDistinct(e, s.toDouble)
+    } |
     FIRST ~> "(" ~> expression <~ ")" ^^ { case exp => First(exp) } |
     AVG ~> "(" ~> expression <~ ")" ^^ { case exp => Average(exp) } |
     MIN ~> "(" ~> expression <~ ")" ^^ { case exp => Min(exp) } |

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/aggregates.scala

@@ -17,6 +17,8 @@
 
 package org.apache.spark.sql.catalyst.expressions
 
+import com.clearspring.analytics.stream.cardinality.HyperLogLog
+
 import org.apache.spark.sql.catalyst.types._
 import org.apache.spark.sql.catalyst.trees
 import org.apache.spark.sql.catalyst.errors.TreeNodeException
@@ -146,7 +148,6 @@ case class MaxFunction(expr: Expression, base: AggregateExpression) extends Aggr
   override def eval(input: Row): Any = currentMax
 }
 
-
 case class Count(child: Expression) extends PartialAggregate with trees.UnaryNode[Expression] {
   override def references = child.references
   override def nullable = false
@@ -166,10 +167,47 @@ case class CountDistinct(expressions: Seq[Expression]) extends AggregateExpressi
   override def references = expressions.flatMap(_.references).toSet
   override def nullable = false
   override def dataType = IntegerType
-  override def toString = s"COUNT(DISTINCT ${expressions.mkString(",")}})"
+  override def toString = s"COUNT(DISTINCT ${expressions.mkString(",")})"
   override def newInstance() = new CountDistinctFunction(expressions, this)
 }
 
+case class ApproxCountDistinctPartition(child: Expression, relativeSD: Double)
+  extends AggregateExpression with trees.UnaryNode[Expression] {
+  override def references = child.references
+  override def nullable = false
+  override def dataType = child.dataType
+  override def toString = s"APPROXIMATE COUNT(DISTINCT $child)"
+  override def newInstance() = new ApproxCountDistinctPartitionFunction(child, this, relativeSD)
+}
+
+case class ApproxCountDistinctMerge(child: Expression, relativeSD: Double)
+  extends AggregateExpression with trees.UnaryNode[Expression] {
+  override def references = child.references
+  override def nullable = false
+  override def dataType = IntegerType
+  override def toString = s"APPROXIMATE COUNT(DISTINCT $child)"
+  override def newInstance() = new ApproxCountDistinctMergeFunction(child, this, relativeSD)
+}
+
+case class ApproxCountDistinct(child: Expression, relativeSD: Double = 0.05)
+  extends PartialAggregate with trees.UnaryNode[Expression] {
+  override def references = child.references
+  override def nullable = false
+  override def dataType = IntegerType
+  override def toString = s"APPROXIMATE COUNT(DISTINCT $child)"
+
+  override def asPartial: SplitEvaluation = {
+    val partialCount =
+      Alias(ApproxCountDistinctPartition(child, relativeSD), "PartialApproxCountDistinct")()
+
+    SplitEvaluation(
+      ApproxCountDistinctMerge(partialCount.toAttribute, relativeSD),
+      partialCount :: Nil)
+  }
+
+  override def newInstance() = new CountDistinctFunction(child :: Nil, this)
+}
+
 case class Average(child: Expression) extends PartialAggregate with trees.UnaryNode[Expression] {
   override def references = child.references
   override def nullable = false
@@ -269,6 +307,42 @@ case class CountFunction(expr: Expression, base: AggregateExpression) extends Ag
   override def eval(input: Row): Any = count
 }
 
+case class ApproxCountDistinctPartitionFunction(
+    expr: Expression,
+    base: AggregateExpression,
+    relativeSD: Double)
+  extends AggregateFunction {
+  def this() = this(null, null, 0) // Required for serialization.
+
+  private val hyperLogLog = new HyperLogLog(relativeSD)
+
+  override def update(input: Row): Unit = {
+    val evaluatedExpr = expr.eval(input)
+    if (evaluatedExpr != null) {
+      hyperLogLog.offer(evaluatedExpr)
+    }
+  }
+
+  override def eval(input: Row): Any = hyperLogLog
+}
+
+case class ApproxCountDistinctMergeFunction(
+    expr: Expression,
+    base: AggregateExpression,
+    relativeSD: Double)
+  extends AggregateFunction {
+  def this() = this(null, null, 0) // Required for serialization.
+
+  private val hyperLogLog = new HyperLogLog(relativeSD)
+
+  override def update(input: Row): Unit = {
+    val evaluatedExpr = expr.eval(input)
+    hyperLogLog.addAll(evaluatedExpr.asInstanceOf[HyperLogLog])
+  }
+
+  override def eval(input: Row): Any = hyperLogLog.cardinality()
+}
+
 case class SumFunction(expr: Expression, base: AggregateExpression) extends AggregateFunction {
   def this() = this(null, null) // Required for serialization.
 

sql/core/src/main/scala/org/apache/spark/sql/api/java/JavaSQLContext.scala

@@ -33,9 +33,9 @@ import org.apache.spark.util.Utils
 /**
  * The entry point for executing Spark SQL queries from a Java program.
  */
-class JavaSQLContext(sparkContext: JavaSparkContext) {
+class JavaSQLContext(val sqlContext: SQLContext) {
 
-  val sqlContext = new SQLContext(sparkContext.sc)
+  def this(sparkContext: JavaSparkContext) = this(new SQLContext(sparkContext.sc))
 
   /**
    * Executes a query expressed in SQL, returning the result as a JavaSchemaRDD

sql/core/src/main/scala/org/apache/spark/sql/execution/SparkSqlSerializer.scala

@@ -21,6 +21,7 @@ import java.nio.ByteBuffer
 
 import scala.reflect.ClassTag
 
+import com.clearspring.analytics.stream.cardinality.HyperLogLog
 import com.esotericsoftware.kryo.io.{Input, Output}
 import com.esotericsoftware.kryo.{Serializer, Kryo}
 
@@ -44,6 +45,8 @@ private[sql] class SparkSqlSerializer(conf: SparkConf) extends KryoSerializer(co
     kryo.register(classOf[scala.collection.Map[_,_]], new MapSerializer)
     kryo.register(classOf[org.apache.spark.sql.catalyst.expressions.GenericRow])
     kryo.register(classOf[org.apache.spark.sql.catalyst.expressions.GenericMutableRow])
+    kryo.register(classOf[com.clearspring.analytics.stream.cardinality.HyperLogLog],
+                  new HyperLogLogSerializer)
     kryo.register(classOf[scala.collection.mutable.ArrayBuffer[_]])
     kryo.register(classOf[scala.math.BigDecimal], new BigDecimalSerializer)
     kryo.setReferences(false)
@@ -81,6 +84,20 @@ private[sql] class BigDecimalSerializer extends Serializer[BigDecimal] {
   }
 }
 
+private[sql] class HyperLogLogSerializer extends Serializer[HyperLogLog] {
+  def write(kryo: Kryo, output: Output, hyperLogLog: HyperLogLog) {
+    val bytes = hyperLogLog.getBytes()
+    output.writeInt(bytes.length)
+    output.writeBytes(bytes)
+  }
+
+  def read(kryo: Kryo, input: Input, tpe: Class[HyperLogLog]): HyperLogLog = {
+    val length = input.readInt()
+    val bytes = input.readBytes(length)
+    HyperLogLog.Builder.build(bytes)
+  }
+}
+
 /**
  * Maps do not have a no arg constructor and so cannot be serialized by default. So, we serialize
  * them as `Array[(k,v)]`.

sql/core/src/test/scala/org/apache/spark/sql/SQLQuerySuite.scala

@@ -96,8 +96,25 @@ class SQLQuerySuite extends QueryTest {
   test("count") {
     checkAnswer(
       sql("SELECT COUNT(*) FROM testData2"),
-      testData2.count()
-    )
+      testData2.count())
+  }
+
+  test("count distinct") {
+    checkAnswer(
+      sql("SELECT COUNT(DISTINCT b) FROM testData2"),
+      2)
+  }
+
+  test("approximate count distinct") {
+    checkAnswer(
+      sql("SELECT APPROXIMATE COUNT(DISTINCT a) FROM testData2"),
+      3)
+  }
+
+  test("approximate count distinct with user provided standard deviation") {
+    checkAnswer(
+      sql("SELECT APPROXIMATE(0.04) COUNT(DISTINCT a) FROM testData2"),
+      3)
   }
 
   // No support for primitive nulls yet.