make caseSensitive configurable

Author: Jacky Li

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

@@ -46,6 +46,8 @@ private[spark] object SQLConf {
   // This is only used for the thriftserver
   val THRIFTSERVER_POOL = "spark.sql.thriftserver.scheduler.pool"
 
+  val CASE_SENSITIVE = "spark.sql.caseSensitive"
+
   object Deprecated {
     val MAPRED_REDUCE_TASKS = "mapred.reduce.tasks"
   }
@@ -148,6 +150,12 @@ private[sql] trait SQLConf {
   private[spark] def columnNameOfCorruptRecord: String =
     getConf(COLUMN_NAME_OF_CORRUPT_RECORD, "_corrupt_record")
 
+  /**
+   * When set to true, analyzer is case sensitive
+   */
+  private[spark] def caseSensitive: Boolean =
+    getConf(CASE_SENSITIVE, "true").toBoolean
+
   /** ********************** SQLConf functionality methods ************ */
 
   /** Set Spark SQL configuration properties. */

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

@@ -65,7 +65,7 @@ class SQLContext(@transient val sparkContext: SparkContext)
 
   @transient
   protected[sql] lazy val analyzer: Analyzer =
-    new Analyzer(catalog, functionRegistry, caseSensitive = true)
+    new Analyzer(catalog, functionRegistry, caseSensitive)
 
   @transient
   protected[sql] lazy val optimizer: Optimizer = DefaultOptimizer