[SPARK-12914] [SQL] generate aggregation with grouping keys

sql/catalyst/src/main/java/org/apache/spark/sql/catalyst/expressions/UnsafeRow.java

@@ -599,7 +599,9 @@ public String toString() {
       build.append(java.lang.Long.toHexString(Platform.getLong(baseObject, baseOffset + i)));
       build.append(',');
     }
-    build.deleteCharAt(build.length() - 1);
+    if (sizeInBytes > 0) {
+      build.deleteCharAt(build.length() - 1);
+    }
     build.append(']');
     return build.toString();
   }

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/codegen/CodeGenerator.scala

@@ -55,6 +55,20 @@ class CodegenContext {
    */
   val references: mutable.ArrayBuffer[Any] = new mutable.ArrayBuffer[Any]()
 
+  /**
+    * Add an object to `references`, create a class member to access it.
+    *
+    * Returns the name of class member.
+    */
+  def addReferenceObj(name: String, obj: Any, className: String = null): String = {
+    val term = freshName(name)
+    val idx = references.length
+    references += obj
+    val clsName = Option(className).getOrElse(obj.getClass.getName)
+    addMutableState(clsName, term, s"this.$term = ($clsName) references[$idx];")
+    term
+  }
+
   /**
     * Holding a list of generated columns as input of current operator, will be used by
     * BoundReference to generate code.

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/codegen/GenerateMutableProjection.scala

@@ -93,7 +93,7 @@ object GenerateMutableProjection extends CodeGenerator[Seq[Expression], () => Mu
             // Can't call setNullAt on DecimalType, because we need to keep the offset
             s"""
               if (this.isNull_$i) {
-                ${ctx.setColumn("mutableRow", e.dataType, i, null)};
+                ${ctx.setColumn("mutableRow", e.dataType, i, "null")};
               } else {
                 ${ctx.setColumn("mutableRow", e.dataType, i, s"this.value_$i")};
               }

sql/core/src/main/scala/org/apache/spark/sql/execution/BufferedRowIterator.java

@@ -17,6 +17,8 @@
 
 package org.apache.spark.sql.execution;
 
+import java.io.IOException;
+
 import scala.collection.Iterator;
 
 import org.apache.spark.sql.catalyst.InternalRow;
@@ -34,7 +36,7 @@ public class BufferedRowIterator {
   // used when there is no column in output
   protected UnsafeRow unsafeRow = new UnsafeRow(0);
 
-  public boolean hasNext() {
+  public boolean hasNext() throws IOException {
     if (currentRow == null) {
       processNext();
     }
@@ -56,7 +58,7 @@ public void setInput(Iterator<InternalRow> iter) {
    *
    * After it's called, if currentRow is still null, it means no more rows left.
    */
-  protected void processNext() {
+  protected void processNext() throws IOException {
     if (input.hasNext()) {
       currentRow = input.next();
     }

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

@@ -25,6 +25,7 @@ import org.apache.spark.sql.catalyst.InternalRow
 import org.apache.spark.sql.catalyst.expressions.{Attribute, BoundReference, Expression, LeafExpression}
 import org.apache.spark.sql.catalyst.expressions.codegen._
 import org.apache.spark.sql.catalyst.rules.Rule
+import org.apache.spark.util.Utils
 
 /**
   * An interface for those physical operators that support codegen.
@@ -41,10 +42,15 @@ trait CodegenSupport extends SparkPlan {
     */
   private var parent: CodegenSupport = null
 
+  /**
+    * Returns the RDD of InternalRow which generates the input rows.
+    */
+  def upstream(): RDD[InternalRow]
+
   /**
     * Returns an input RDD of InternalRow and Java source code to process them.
     */
-  def produce(ctx: CodegenContext, parent: CodegenSupport): (RDD[InternalRow], String) = {
+  def produce(ctx: CodegenContext, parent: CodegenSupport): String = {
     this.parent = parent
     doProduce(ctx)
   }
@@ -66,16 +72,40 @@ trait CodegenSupport extends SparkPlan {
     *     # call consume(), wich will call parent.doConsume()
     *   }
     */
-  protected def doProduce(ctx: CodegenContext): (RDD[InternalRow], String)
+  protected def doProduce(ctx: CodegenContext): String
 
   /**
-    * Consume the columns generated from current SparkPlan, call it's parent or create an iterator.
+    * Consume the columns generated from current SparkPlan, call it's parent.
     */
-  protected def consume(ctx: CodegenContext, columns: Seq[ExprCode]): String = {
-    assert(columns.length == output.length)
-    parent.doConsume(ctx, this, columns)
+  def consume(ctx: CodegenContext, input: Seq[ExprCode], row: String = null): String = {
+    if (input != null) {
+      assert(input.length == output.length)
+    }
+    parent.consumeChild(ctx, this, input, row)
   }
 
+  /**
+    * Consume the columns generated from it's child, call doConsume() or emit the rows.
+    */
+  def consumeChild(
+      ctx: CodegenContext,
+      child: SparkPlan,
+      input: Seq[ExprCode],
+      row: String = null): String = {
+    if (row != null) {
+      ctx.currentVars = null
+      ctx.INPUT_ROW = row
+      val evals = child.output.zipWithIndex.map { case (attr, i) =>
+        BoundReference(i, attr.dataType, attr.nullable).gen(ctx)
+      }
+      s"""
+         | ${evals.map(_.code).mkString("\n")}
+         | ${doConsume(ctx, child, evals)}
+       """.stripMargin
+    } else {
+      doConsume(ctx, child, input)
+    }
+  }
 
   /**
     * Generate the Java source code to process the rows from child SparkPlan.
@@ -89,7 +119,9 @@ trait CodegenSupport extends SparkPlan {
     *     # call consume(), which will call parent.doConsume()
     *   }
     */
-  def doConsume(ctx: CodegenContext, child: SparkPlan, input: Seq[ExprCode]): String
+  protected def doConsume(ctx: CodegenContext, child: SparkPlan, input: Seq[ExprCode]): String = {
+    throw new UnsupportedOperationException
+  }
 }
 
 
@@ -105,24 +137,23 @@ case class InputAdapter(child: SparkPlan) extends LeafNode with CodegenSupport {
 
   override def supportCodegen: Boolean = true
 
-  override def doProduce(ctx: CodegenContext): (RDD[InternalRow], String) = {
+  override def upstream(): RDD[InternalRow] = {
+    child.execute()
+  }
+
+  override def doProduce(ctx: CodegenContext): String = {
     val exprs = output.zipWithIndex.map(x => new BoundReference(x._2, x._1.dataType, true))
     val row = ctx.freshName("row")
     ctx.INPUT_ROW = row
     ctx.currentVars = null
     val columns = exprs.map(_.gen(ctx))
-    val code = s"""
+    s"""
        |  while (input.hasNext()) {
        |   InternalRow $row = (InternalRow) input.next();
        |   ${columns.map(_.code).mkString("\n")}
        |   ${consume(ctx, columns)}
        | }
      """.stripMargin
-    (child.execute(), code)
-  }
-
-  def doConsume(ctx: CodegenContext, child: SparkPlan, input: Seq[ExprCode]): String = {
-    throw new UnsupportedOperationException
   }
 
   override def doExecute(): RDD[InternalRow] = {
@@ -150,9 +181,11 @@ case class InputAdapter(child: SparkPlan) extends LeafNode with CodegenSupport {
   *                                                doProduce() ---> execute()
   *                                                   |
   *                                                consume()
-  *                          doConsume()  ------------|
+  *                        consumeChild() <-----------|
   *                             |
-  *  doConsume()  <-----    consume()
+  *                          doConsume()
+  *                             |
+  *  consumeChild()  <-----  consume()
   *
   * SparkPlan A should override doProduce() and doConsume().
   *
@@ -166,33 +199,36 @@ case class WholeStageCodegen(plan: CodegenSupport, children: Seq[SparkPlan])
 
   override def doExecute(): RDD[InternalRow] = {
     val ctx = new CodegenContext
-    val (rdd, code) = plan.produce(ctx, this)
+    val code = plan.produce(ctx, this)
     val references = ctx.references.toArray
     val source = s"""
       public Object generate(Object[] references) {
-       return new GeneratedIterator(references);
+        return new GeneratedIterator(references);
       }
 
       class GeneratedIterator extends org.apache.spark.sql.execution.BufferedRowIterator {
 
-       private Object[] references;
-       ${ctx.declareMutableStates()}
+        private Object[] references;
+        ${ctx.declareMutableStates()}
+        ${ctx.declareAddedFunctions()}
 
-       public GeneratedIterator(Object[] references) {
+        public GeneratedIterator(Object[] references) {
          this.references = references;
          ${ctx.initMutableStates()}
-       }
+        }
 
-       protected void processNext() {
+        protected void processNext() throws java.io.IOException {
          $code
-       }
+        }
       }
-     """
+      """
+
     // try to compile, helpful for debug
     // println(s"${CodeFormatter.format(source)}")
     CodeGenerator.compile(source)
 
-    rdd.mapPartitions { iter =>
+    plan.upstream().mapPartitions { iter =>
+
       val clazz = CodeGenerator.compile(source)
       val buffer = clazz.generate(references).asInstanceOf[BufferedRowIterator]
       buffer.setInput(iter)
@@ -203,29 +239,47 @@ case class WholeStageCodegen(plan: CodegenSupport, children: Seq[SparkPlan])
     }
   }
 
-  override def doProduce(ctx: CodegenContext): (RDD[InternalRow], String) = {
+  override def upstream(): RDD[InternalRow] = {
     throw new UnsupportedOperationException
   }
 
-  override def doConsume(ctx: CodegenContext, child: SparkPlan, input: Seq[ExprCode]): String = {
-    if (input.nonEmpty) {
-      val colExprs = output.zipWithIndex.map { case (attr, i) =>
-        BoundReference(i, attr.dataType, attr.nullable)
-      }
-      // generate the code to create a UnsafeRow
-      ctx.currentVars = input
-      val code = GenerateUnsafeProjection.createCode(ctx, colExprs, false)
-      s"""
-         | ${code.code.trim}
-         | currentRow = ${code.value};
-         | return;
-     """.stripMargin
-    } else {
-      // There is no columns
+  override def doProduce(ctx: CodegenContext): String = {
+    throw new UnsupportedOperationException
+  }
+
+  override def consumeChild(
+      ctx: CodegenContext,
+      child: SparkPlan,
+      input: Seq[ExprCode],
+      row: String = null): String = {
+
+    if (row != null) {
+      // There is an UnsafeRow already
       s"""
-         | currentRow = unsafeRow;
+         | currentRow = $row;
          | return;
        """.stripMargin
+    } else {
+      assert(input != null)
+      if (input.nonEmpty) {
+        val colExprs = output.zipWithIndex.map { case (attr, i) =>
+          BoundReference(i, attr.dataType, attr.nullable)
+        }
+        // generate the code to create a UnsafeRow
+        ctx.currentVars = input
+        val code = GenerateUnsafeProjection.createCode(ctx, colExprs, false)
+        s"""
+           | ${code.code.trim}
+           | currentRow = ${code.value};
+           | return;
+         """.stripMargin
+      } else {
+        // There is no columns
+        s"""
+           | currentRow = unsafeRow;
+           | return;
+         """.stripMargin
+      }
     }
   }
 
@@ -246,7 +300,7 @@ case class WholeStageCodegen(plan: CodegenSupport, children: Seq[SparkPlan])
     builder.append(simpleString)
     builder.append("\n")
 
-    plan.generateTreeString(depth + 1, lastChildren :+children.isEmpty :+ true, builder)
+    plan.generateTreeString(depth + 2, lastChildren :+ false :+ true, builder)
     if (children.nonEmpty) {
       children.init.foreach(_.generateTreeString(depth + 1, lastChildren :+ false, builder))
       children.last.generateTreeString(depth + 1, lastChildren :+ true, builder)
@@ -286,13 +340,14 @@ private[sql] case class CollapseCodegenStages(sqlContext: SQLContext) extends Ru
         case plan: CodegenSupport if supportCodegen(plan) &&
           // Whole stage codegen is only useful when there are at least two levels of operators that
           // support it (save at least one projection/iterator).
-          plan.children.exists(supportCodegen) =>
+          (Utils.isTesting || plan.children.exists(supportCodegen)) =>
 
           var inputs = ArrayBuffer[SparkPlan]()
           val combined = plan.transform {
             case p if !supportCodegen(p) =>
-              inputs += p
-              InputAdapter(p)
+              val input = apply(p)  // collapse them recursively
+              inputs += input
+              InputAdapter(input)
           }.asInstanceOf[CodegenSupport]
           WholeStageCodegen(combined, inputs)
       }