[SPARK-6675][SQL]Hive setConf issue

sql/core/src/main/scala/org/apache/spark/sql/SQLConf.scala

@@ -199,8 +199,15 @@ private[sql] class SQLConf extends Serializable {
   /** ********************** SQLConf functionality methods ************ */
 
   /** Set Spark SQL configuration properties. */
-  def setConf(props: Properties): Unit = settings.synchronized {
-    props.foreach { case (k, v) => settings.put(k, v) }
+  def setConf(props: Properties, overwrite: Boolean = true): Unit = settings.synchronized {
+    if (overwrite) {
+      props.foreach { case (k, v) => settings.put(k, v) }  
+    } else {
+      props
+        .filter(p => !settings.containsKey(p._1))
+        .foreach { case (k, v) => settings.put(k, v) }
+    }
+
   }
 
   /** Set the given Spark SQL configuration property. */

sql/core/src/main/scala/org/apache/spark/sql/SQLContext.scala

@@ -73,7 +73,7 @@ class SQLContext(@transient val sparkContext: SparkContext)
    *
    * @group config
    */
-  def setConf(props: Properties): Unit = conf.setConf(props)
+  def setConf(props: Properties, overwrite: Boolean = true): Unit = conf.setConf(props, overwrite)
 
   /**
    * Set the given Spark SQL configuration property.

sql/hive/src/main/scala/org/apache/spark/sql/hive/HiveContext.scala

@@ -264,7 +264,7 @@ class HiveContext(sc: SparkContext) extends SQLContext(sc) {
     }
 
     protected[hive] lazy val hiveconf: HiveConf = {
-      setConf(sessionState.getConf.getAllProperties)
+      setConf(sessionState.getConf.getAllProperties, false)
       sessionState.getConf
     }
 

sql/hive/src/test/scala/org/apache/spark/sql/hive/HiveContextInitSuite.scala

@@ -0,0 +1,32 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.spark.sql.hive
+
+import org.apache.spark.sql.hive.test.TestHive
+import org.scalatest.FunSuite
+
+class HiveContextInitSuite extends FunSuite {
+  test("SPARK-6675 Hive setConf") {
+    val hc = new HiveContext(TestHive.sparkContext)
+    hc.setConf("hive.metastore.warehouse.dir", "/home/spark/hive/warehouse_test")
+    hc.setConf("spark.sql.shuffle.partitions", "10")
+    assert(hc.getAllConfs.get("hive.metastore.warehouse.dir")
+       .toList.contains("/home/spark/hive/warehouse_test"))
+    assert(hc.getAllConfs.get("spark.sql.shuffle.partitions").toList.contains("10"))
+  }
+}