1 files changed, 44 insertions, 9 deletions

diff --git a/sql/core/src/main/scala/org/apache/spark/sql/execution/debug/package.scala b/sql/core/src/main/scala/org/apache/spark/sql/execution/debug/package.scala
index 5e573b3159..17eae88b49 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/execution/debug/package.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/execution/debug/package.scala
@@ -25,7 +25,7 @@ import org.apache.spark.rdd.RDD
 import org.apache.spark.sql._
 import org.apache.spark.sql.catalyst.InternalRow
 import org.apache.spark.sql.catalyst.expressions.Attribute
-import org.apache.spark.sql.catalyst.expressions.codegen.{CodegenContext, ExprCode}
+import org.apache.spark.sql.catalyst.expressions.codegen.{CodeFormatter, CodegenContext, ExprCode}
 import org.apache.spark.sql.catalyst.trees.TreeNodeRef
 import org.apache.spark.sql.internal.SQLConf
 
@@ -35,12 +35,38 @@ import org.apache.spark.sql.internal.SQLConf
  * Usage:
  * {{{
  *   import org.apache.spark.sql.execution.debug._
- *   sql("SELECT key FROM src").debug()
- *   dataFrame.typeCheck()
+ *   sql("SELECT 1").debug()
+ *   sql("SELECT 1").debugCodegen()
  * }}}
  */
 package object debug {
 
+  /** Helper function to evade the println() linter. */
+  private def debugPrint(msg: String): Unit = {
+    // scalastyle:off println
+    println(msg)
+    // scalastyle:on println
+  }
+
+  def codegenString(plan: SparkPlan): String = {
+    val codegenSubtrees = new collection.mutable.HashSet[WholeStageCodegen]()
+    plan transform {
+      case s: WholeStageCodegen =>
+        codegenSubtrees += s
+        s
+      case s => s
+    }
+    var output = s"Found ${codegenSubtrees.size} WholeStageCodegen subtrees.\n"
+    for ((s, i) <- codegenSubtrees.toSeq.zipWithIndex) {
+      output += s"== Subtree ${i + 1} / ${codegenSubtrees.size} ==\n"
+      output += s
+      output += "\nGenerated code:\n"
+      val (_, source) = s.doCodeGen()
+      output += s"${CodeFormatter.format(source)}\n"
+    }
+    output
+  }
+
   /**
    * Augments [[SQLContext]] with debug methods.
    */
@@ -51,9 +77,9 @@ package object debug {
   }
 
   /**
-   * Augments [[DataFrame]]s with debug methods.
+   * Augments [[Dataset]]s with debug methods.
    */
-  implicit class DebugQuery(query: DataFrame) extends Logging {
+  implicit class DebugQuery(query: Dataset[_]) extends Logging {
     def debug(): Unit = {
       val plan = query.queryExecution.executedPlan
       val visited = new collection.mutable.HashSet[TreeNodeRef]()
@@ -62,12 +88,20 @@ package object debug {
           visited += new TreeNodeRef(s)
           DebugNode(s)
       }
-      logDebug(s"Results returned: ${debugPlan.execute().count()}")
+      debugPrint(s"Results returned: ${debugPlan.execute().count()}")
       debugPlan.foreach {
         case d: DebugNode => d.dumpStats()
         case _ =>
       }
     }
+
+    /**
+     * Prints to stdout all the generated code found in this plan (i.e. the output of each
+     * WholeStageCodegen subtree).
+     */
+    def debugCodegen(): Unit = {
+      debugPrint(codegenString(query.queryExecution.executedPlan))
+    }
   }
 
   private[sql] case class DebugNode(child: SparkPlan) extends UnaryNode with CodegenSupport {
@@ -87,6 +121,7 @@ package object debug {
 
     /**
      * A collection of metrics for each column of output.
+     *
      * @param elementTypes the actual runtime types for the output.  Useful when there are bugs
      *                     causing the wrong data to be projected.
      */
@@ -99,11 +134,11 @@ package object debug {
     val columnStats: Array[ColumnMetrics] = Array.fill(child.output.size)(new ColumnMetrics())
 
     def dumpStats(): Unit = {
-      logDebug(s"== ${child.simpleString} ==")
-      logDebug(s"Tuples output: ${tupleCount.value}")
+      debugPrint(s"== ${child.simpleString} ==")
+      debugPrint(s"Tuples output: ${tupleCount.value}")
       child.output.zip(columnStats).foreach { case (attr, metric) =>
         val actualDataTypes = metric.elementTypes.value.mkString("{", ",", "}")
-        logDebug(s" ${attr.name} ${attr.dataType}: $actualDataTypes")
+        debugPrint(s" ${attr.name} ${attr.dataType}: $actualDataTypes")
       }
     }