[SPARK-2554][SQL] CountDistinct partial aggregation and object alloca…

…tion improvements

Author: Michael Armbrust <michael@databricks.com>
Author: Gregory Owen <greowen@gmail.com>

Closes apache#1935 from marmbrus/countDistinctPartial and squashes the following commits:

5c7848d [Michael Armbrust] turn off caching in the constructor
8074a80 [Michael Armbrust] fix tests
32d216f [Michael Armbrust] reynolds comments
c122cca [Michael Armbrust] Address comments, add tests
b2e8ef3 [Michael Armbrust] Merge remote-tracking branch 'origin/master' into countDistinctPartial
fae38f4 [Michael Armbrust] Fix style
fdca896 [Michael Armbrust] cleanup
93d0f64 [Michael Armbrust] metastore concurrency fix.
db44a30 [Michael Armbrust] JIT hax.
3868f6c [Michael Armbrust] Merge pull request alteryx#9 from GregOwen/countDistinctPartial
c9e67de [Gregory Owen] Made SpecificRow and types serializable by Kryo
2b46c4b [Michael Armbrust] Merge remote-tracking branch 'origin/master' into countDistinctPartial
8ff6402 [Michael Armbrust] Add specific row.
58d15f1 [Michael Armbrust] disable codegen logging
87d101d [Michael Armbrust] Fix isNullAt bug
abee26d [Michael Armbrust] WIP
27984d0 [Michael Armbrust] Merge remote-tracking branch 'origin/master' into countDistinctPartial
57ae3b1 [Michael Armbrust] Fix order dependent test
b3d0f64 [Michael Armbrust] Add golden files.
c1f7114 [Michael Armbrust] Improve tests / fix serialization.
f31b8ad [Michael Armbrust] more fixes
38c7449 [Michael Armbrust] comments and style
9153652 [Michael Armbrust] better toString
d494598 [Michael Armbrust] Fix tests now that the planner is better
41fbd1d [Michael Armbrust] Never try and create an empty hash set.
050bb97 [Michael Armbrust] Skip no-arg constructors for kryo,
bd08239 [Michael Armbrust] WIP
213ada8 [Michael Armbrust] First draft of partially aggregated and code generated count distinct / max

(cherry picked from commit 7e191fe)
Signed-off-by: Michael Armbrust <michael@databricks.com>

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

@@ -27,7 +27,8 @@ class InterpretedProjection(expressions: Seq[Expression]) extends Projection {
   def this(expressions: Seq[Expression], inputSchema: Seq[Attribute]) =
     this(expressions.map(BindReferences.bindReference(_, inputSchema)))
 
-  protected val exprArray = expressions.toArray
+  // null check is required for when Kryo invokes the no-arg constructor.
+  protected val exprArray = if (expressions != null) expressions.toArray else null
 
   def apply(input: Row): Row = {
     val outputArray = new Array[Any](exprArray.length)
@@ -109,7 +110,346 @@ class JoinedRow extends Row {
   def apply(i: Int) =
     if (i < row1.size) row1(i) else row2(i - row1.size)
 
-  def isNullAt(i: Int) = apply(i) == null
+  def isNullAt(i: Int) =
+    if (i < row1.size) row1.isNullAt(i) else row2.isNullAt(i - row1.size)
+
+  def getInt(i: Int): Int =
+    if (i < row1.size) row1.getInt(i) else row2.getInt(i - row1.size)
+
+  def getLong(i: Int): Long =
+    if (i < row1.size) row1.getLong(i) else row2.getLong(i - row1.size)
+
+  def getDouble(i: Int): Double =
+    if (i < row1.size) row1.getDouble(i) else row2.getDouble(i - row1.size)
+
+  def getBoolean(i: Int): Boolean =
+    if (i < row1.size) row1.getBoolean(i) else row2.getBoolean(i - row1.size)
+
+  def getShort(i: Int): Short =
+    if (i < row1.size) row1.getShort(i) else row2.getShort(i - row1.size)
+
+  def getByte(i: Int): Byte =
+    if (i < row1.size) row1.getByte(i) else row2.getByte(i - row1.size)
+
+  def getFloat(i: Int): Float =
+    if (i < row1.size) row1.getFloat(i) else row2.getFloat(i - row1.size)
+
+  def getString(i: Int): String =
+    if (i < row1.size) row1.getString(i) else row2.getString(i - row1.size)
+
+  def copy() = {
+    val totalSize = row1.size + row2.size
+    val copiedValues = new Array[Any](totalSize)
+    var i = 0
+    while(i < totalSize) {
+      copiedValues(i) = apply(i)
+      i += 1
+    }
+    new GenericRow(copiedValues)
+  }
+
+  override def toString() = {
+    val row = (if (row1 != null) row1 else Seq[Any]()) ++ (if (row2 != null) row2 else Seq[Any]())
+    s"[${row.mkString(",")}]"
+  }
+}
+
+/**
+ * JIT HACK: Replace with macros
+ * The `JoinedRow` class is used in many performance critical situation.  Unfortunately, since there
+ * are multiple different types of `Rows` that could be stored as `row1` and `row2` most of the
+ * calls in the critical path are polymorphic.  By creating special versions of this class that are
+ * used in only a single location of the code, we increase the chance that only a single type of
+ * Row will be referenced, increasing the opportunity for the JIT to play tricks.  This sounds
+ * crazy but in benchmarks it had noticeable effects.
+ */
+class JoinedRow2 extends Row {
+  private[this] var row1: Row = _
+  private[this] var row2: Row = _
+
+  def this(left: Row, right: Row) = {
+    this()
+    row1 = left
+    row2 = right
+  }
+
+  /** Updates this JoinedRow to used point at two new base rows.  Returns itself. */
+  def apply(r1: Row, r2: Row): Row = {
+    row1 = r1
+    row2 = r2
+    this
+  }
+
+  /** Updates this JoinedRow by updating its left base row.  Returns itself. */
+  def withLeft(newLeft: Row): Row = {
+    row1 = newLeft
+    this
+  }
+
+  /** Updates this JoinedRow by updating its right base row.  Returns itself. */
+  def withRight(newRight: Row): Row = {
+    row2 = newRight
+    this
+  }
+
+  def iterator = row1.iterator ++ row2.iterator
+
+  def length = row1.length + row2.length
+
+  def apply(i: Int) =
+    if (i < row1.size) row1(i) else row2(i - row1.size)
+
+  def isNullAt(i: Int) =
+    if (i < row1.size) row1.isNullAt(i) else row2.isNullAt(i - row1.size)
+
+  def getInt(i: Int): Int =
+    if (i < row1.size) row1.getInt(i) else row2.getInt(i - row1.size)
+
+  def getLong(i: Int): Long =
+    if (i < row1.size) row1.getLong(i) else row2.getLong(i - row1.size)
+
+  def getDouble(i: Int): Double =
+    if (i < row1.size) row1.getDouble(i) else row2.getDouble(i - row1.size)
+
+  def getBoolean(i: Int): Boolean =
+    if (i < row1.size) row1.getBoolean(i) else row2.getBoolean(i - row1.size)
+
+  def getShort(i: Int): Short =
+    if (i < row1.size) row1.getShort(i) else row2.getShort(i - row1.size)
+
+  def getByte(i: Int): Byte =
+    if (i < row1.size) row1.getByte(i) else row2.getByte(i - row1.size)
+
+  def getFloat(i: Int): Float =
+    if (i < row1.size) row1.getFloat(i) else row2.getFloat(i - row1.size)
+
+  def getString(i: Int): String =
+    if (i < row1.size) row1.getString(i) else row2.getString(i - row1.size)
+
+  def copy() = {
+    val totalSize = row1.size + row2.size
+    val copiedValues = new Array[Any](totalSize)
+    var i = 0
+    while(i < totalSize) {
+      copiedValues(i) = apply(i)
+      i += 1
+    }
+    new GenericRow(copiedValues)
+  }
+
+  override def toString() = {
+    val row = (if (row1 != null) row1 else Seq[Any]()) ++ (if (row2 != null) row2 else Seq[Any]())
+    s"[${row.mkString(",")}]"
+  }
+}
+
+/**
+ * JIT HACK: Replace with macros
+ */
+class JoinedRow3 extends Row {
+  private[this] var row1: Row = _
+  private[this] var row2: Row = _
+
+  def this(left: Row, right: Row) = {
+    this()
+    row1 = left
+    row2 = right
+  }
+
+  /** Updates this JoinedRow to used point at two new base rows.  Returns itself. */
+  def apply(r1: Row, r2: Row): Row = {
+    row1 = r1
+    row2 = r2
+    this
+  }
+
+  /** Updates this JoinedRow by updating its left base row.  Returns itself. */
+  def withLeft(newLeft: Row): Row = {
+    row1 = newLeft
+    this
+  }
+
+  /** Updates this JoinedRow by updating its right base row.  Returns itself. */
+  def withRight(newRight: Row): Row = {
+    row2 = newRight
+    this
+  }
+
+  def iterator = row1.iterator ++ row2.iterator
+
+  def length = row1.length + row2.length
+
+  def apply(i: Int) =
+    if (i < row1.size) row1(i) else row2(i - row1.size)
+
+  def isNullAt(i: Int) =
+    if (i < row1.size) row1.isNullAt(i) else row2.isNullAt(i - row1.size)
+
+  def getInt(i: Int): Int =
+    if (i < row1.size) row1.getInt(i) else row2.getInt(i - row1.size)
+
+  def getLong(i: Int): Long =
+    if (i < row1.size) row1.getLong(i) else row2.getLong(i - row1.size)
+
+  def getDouble(i: Int): Double =
+    if (i < row1.size) row1.getDouble(i) else row2.getDouble(i - row1.size)
+
+  def getBoolean(i: Int): Boolean =
+    if (i < row1.size) row1.getBoolean(i) else row2.getBoolean(i - row1.size)
+
+  def getShort(i: Int): Short =
+    if (i < row1.size) row1.getShort(i) else row2.getShort(i - row1.size)
+
+  def getByte(i: Int): Byte =
+    if (i < row1.size) row1.getByte(i) else row2.getByte(i - row1.size)
+
+  def getFloat(i: Int): Float =
+    if (i < row1.size) row1.getFloat(i) else row2.getFloat(i - row1.size)
+
+  def getString(i: Int): String =
+    if (i < row1.size) row1.getString(i) else row2.getString(i - row1.size)
+
+  def copy() = {
+    val totalSize = row1.size + row2.size
+    val copiedValues = new Array[Any](totalSize)
+    var i = 0
+    while(i < totalSize) {
+      copiedValues(i) = apply(i)
+      i += 1
+    }
+    new GenericRow(copiedValues)
+  }
+
+  override def toString() = {
+    val row = (if (row1 != null) row1 else Seq[Any]()) ++ (if (row2 != null) row2 else Seq[Any]())
+    s"[${row.mkString(",")}]"
+  }
+}
+
+/**
+ * JIT HACK: Replace with macros
+ */
+class JoinedRow4 extends Row {
+  private[this] var row1: Row = _
+  private[this] var row2: Row = _
+
+  def this(left: Row, right: Row) = {
+    this()
+    row1 = left
+    row2 = right
+  }
+
+  /** Updates this JoinedRow to used point at two new base rows.  Returns itself. */
+  def apply(r1: Row, r2: Row): Row = {
+    row1 = r1
+    row2 = r2
+    this
+  }
+
+  /** Updates this JoinedRow by updating its left base row.  Returns itself. */
+  def withLeft(newLeft: Row): Row = {
+    row1 = newLeft
+    this
+  }
+
+  /** Updates this JoinedRow by updating its right base row.  Returns itself. */
+  def withRight(newRight: Row): Row = {
+    row2 = newRight
+    this
+  }
+
+  def iterator = row1.iterator ++ row2.iterator
+
+  def length = row1.length + row2.length
+
+  def apply(i: Int) =
+    if (i < row1.size) row1(i) else row2(i - row1.size)
+
+  def isNullAt(i: Int) =
+    if (i < row1.size) row1.isNullAt(i) else row2.isNullAt(i - row1.size)
+
+  def getInt(i: Int): Int =
+    if (i < row1.size) row1.getInt(i) else row2.getInt(i - row1.size)
+
+  def getLong(i: Int): Long =
+    if (i < row1.size) row1.getLong(i) else row2.getLong(i - row1.size)
+
+  def getDouble(i: Int): Double =
+    if (i < row1.size) row1.getDouble(i) else row2.getDouble(i - row1.size)
+
+  def getBoolean(i: Int): Boolean =
+    if (i < row1.size) row1.getBoolean(i) else row2.getBoolean(i - row1.size)
+
+  def getShort(i: Int): Short =
+    if (i < row1.size) row1.getShort(i) else row2.getShort(i - row1.size)
+
+  def getByte(i: Int): Byte =
+    if (i < row1.size) row1.getByte(i) else row2.getByte(i - row1.size)
+
+  def getFloat(i: Int): Float =
+    if (i < row1.size) row1.getFloat(i) else row2.getFloat(i - row1.size)
+
+  def getString(i: Int): String =
+    if (i < row1.size) row1.getString(i) else row2.getString(i - row1.size)
+
+  def copy() = {
+    val totalSize = row1.size + row2.size
+    val copiedValues = new Array[Any](totalSize)
+    var i = 0
+    while(i < totalSize) {
+      copiedValues(i) = apply(i)
+      i += 1
+    }
+    new GenericRow(copiedValues)
+  }
+
+  override def toString() = {
+    val row = (if (row1 != null) row1 else Seq[Any]()) ++ (if (row2 != null) row2 else Seq[Any]())
+    s"[${row.mkString(",")}]"
+  }
+}
+
+/**
+ * JIT HACK: Replace with macros
+ */
+class JoinedRow5 extends Row {
+  private[this] var row1: Row = _
+  private[this] var row2: Row = _
+
+  def this(left: Row, right: Row) = {
+    this()
+    row1 = left
+    row2 = right
+  }
+
+  /** Updates this JoinedRow to used point at two new base rows.  Returns itself. */
+  def apply(r1: Row, r2: Row): Row = {
+    row1 = r1
+    row2 = r2
+    this
+  }
+
+  /** Updates this JoinedRow by updating its left base row.  Returns itself. */
+  def withLeft(newLeft: Row): Row = {
+    row1 = newLeft
+    this
+  }
+
+  /** Updates this JoinedRow by updating its right base row.  Returns itself. */
+  def withRight(newRight: Row): Row = {
+    row2 = newRight
+    this
+  }
+
+  def iterator = row1.iterator ++ row2.iterator
+
+  def length = row1.length + row2.length
+
+  def apply(i: Int) =
+    if (i < row1.size) row1(i) else row2(i - row1.size)
+
+  def isNullAt(i: Int) =
+    if (i < row1.size) row1.isNullAt(i) else row2.isNullAt(i - row1.size)
 
   def getInt(i: Int): Int =
     if (i < row1.size) row1.getInt(i) else row2.getInt(i - row1.size)

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

@@ -127,7 +127,7 @@ object EmptyRow extends Row {
  * the array is not copied, and thus could technically be mutated after creation, this is not
  * allowed.
  */
-class GenericRow(protected[catalyst] val values: Array[Any]) extends Row {
+class GenericRow(protected[sql] val values: Array[Any]) extends Row {
   /** No-arg constructor for serialization. */
   def this() = this(null)