[SPARK-7204] [SQL] Fix callSite for Dataframe and SQL operations

This patch adds SQL to the set of excluded libraries when
generating a callSite. This makes the callSite mechanism work
properly for the data frame API. I also added a small improvement for
JDBC queries where we just use the string "Spark JDBC Server Query"
instead of trying to give a callsite that doesn't make any sense
to the user.

Before (DF):
![screen shot 2015-04-28 at 1 29 26 pm](https://cloud.githubusercontent.com/assets/320616/7380170/ef63bfb0-edae-11e4-989c-f88a5ba6bbee.png)

After (DF):
![screen shot 2015-04-28 at 1 34 58 pm](https://cloud.githubusercontent.com/assets/320616/7380181/fa7f6d90-edae-11e4-9559-26f163ed63b8.png)

After (JDBC):
![screen shot 2015-04-28 at 2 00 10 pm](https://cloud.githubusercontent.com/assets/320616/7380185/02f5b2a4-edaf-11e4-8e5b-99bdc3df66dd.png)

Author: Patrick Wendell <[email protected]>

Closes apache#5757 from pwendell/dataframes and squashes the following commits:

0d931a4 [Patrick Wendell] Attempting to fix PySpark tests
85bf740 [Patrick Wendell] [SPARK-7204] Fix callsite for dataframe operations.

core/src/main/scala/org/apache/spark/util/Utils.scala

@@ -1299,16 +1299,18 @@ private[spark] object Utils extends Logging {
   }
 
   /** Default filtering function for finding call sites using `getCallSite`. */
-  private def coreExclusionFunction(className: String): Boolean = {
-    // A regular expression to match classes of the "core" Spark API that we want to skip when
-    // finding the call site of a method.
+  private def sparkInternalExclusionFunction(className: String): Boolean = {
+    // A regular expression to match classes of the internal Spark API's
+    // that we want to skip when finding the call site of a method.
     val SPARK_CORE_CLASS_REGEX =
       """^org\.apache\.spark(\.api\.java)?(\.util)?(\.rdd)?(\.broadcast)?\.[A-Z]""".r
+    val SPARK_SQL_CLASS_REGEX = """^org\.apache\.spark\.sql.*""".r
     val SCALA_CORE_CLASS_PREFIX = "scala"
-    val isSparkCoreClass = SPARK_CORE_CLASS_REGEX.findFirstIn(className).isDefined
+    val isSparkClass = SPARK_CORE_CLASS_REGEX.findFirstIn(className).isDefined ||
+      SPARK_SQL_CLASS_REGEX.findFirstIn(className).isDefined
     val isScalaClass = className.startsWith(SCALA_CORE_CLASS_PREFIX)
     // If the class is a Spark internal class or a Scala class, then exclude.
-    isSparkCoreClass || isScalaClass
+    isSparkClass || isScalaClass
   }
 
   /**
@@ -1318,7 +1320,7 @@ private[spark] object Utils extends Logging {
    *
    * @param skipClass Function that is used to exclude non-user-code classes.
    */
-  def getCallSite(skipClass: String => Boolean = coreExclusionFunction): CallSite = {
+  def getCallSite(skipClass: String => Boolean = sparkInternalExclusionFunction): CallSite = {
     // Keep crawling up the stack trace until we find the first function not inside of the spark
     // package. We track the last (shallowest) contiguous Spark method. This might be an RDD
     // transformation, a SparkContext function (such as parallelize), or anything else that leads
@@ -1357,9 +1359,17 @@ private[spark] object Utils extends Logging {
     }
 
     val callStackDepth = System.getProperty("spark.callstack.depth", "20").toInt
-    CallSite(
-      shortForm = s"$lastSparkMethod at $firstUserFile:$firstUserLine",
-      longForm = callStack.take(callStackDepth).mkString("\n"))
+    val shortForm =
+      if (firstUserFile == "HiveSessionImpl.java") {
+        // To be more user friendly, show a nicer string for queries submitted from the JDBC
+        // server.
+        "Spark JDBC Server Query"
+      } else {
+        s"$lastSparkMethod at $firstUserFile:$firstUserLine"
+      }
+    val longForm = callStack.take(callStackDepth).mkString("\n")
+
+    CallSite(shortForm, longForm)
   }
 
   /** Return a string containing part of a file from byte 'start' to 'end'. */

python/pyspark/sql/dataframe.py

@@ -237,7 +237,8 @@ def explain(self, extended=False):
         :param extended: boolean, default ``False``. If ``False``, prints only the physical plan.
 
         >>> df.explain()
-        PhysicalRDD [age#0,name#1], MapPartitionsRDD[...] at mapPartitions at SQLContext.scala:...
+        PhysicalRDD [age#0,name#1], MapPartitionsRDD[...] at applySchemaToPythonRDD at\
+          NativeMethodAccessorImpl.java:...
 
         >>> df.explain(True)
         == Parsed Logical Plan ==