[SPARK-19318][SQL] Fix to treat JDBC connection properties specified by the user in case-sensitive manner.

## What changes were proposed in this pull request?
The reason for test failure is that the property “oracle.jdbc.mapDateToTimestamp” set by the test was getting converted into all lower case. Oracle database expects this property in case-sensitive manner.

This test was passing in previous releases because connection properties were sent as user specified for the test case scenario. Fixes to handle all option uniformly in case-insensitive manner, converted the JDBC connection properties also to lower case.

This PR  enhances CaseInsensitiveMap to keep track of input case-sensitive keys , and uses those when creating connection properties that are passed to the JDBC connection.

Alternative approach PR https://github.com/apache/spark/pull/16847  is to pass original input keys to JDBC data source by adding check in the  Data source class and handle case-insensitivity in the JDBC source code.

## How was this patch tested?
Added new test cases to JdbcSuite , and OracleIntegrationSuite. Ran docker integration tests passed on my laptop, all tests passed successfully.

Author: sureshthalamati <suresh.thalamati@gmail.com>

Closes #16891 from sureshthalamati/jdbc_case_senstivity_props_fix-SPARK-19318.

3 files changed, 7 insertions, 6 deletions

diff --git a/sql/hive/src/main/scala/org/apache/spark/sql/hive/HiveExternalCatalog.scala b/sql/hive/src/main/scala/org/apache/spark/sql/hive/HiveExternalCatalog.scala
index 1fc8e8ea9f..ea48256147 100644
--- a/sql/hive/src/main/scala/org/apache/spark/sql/hive/HiveExternalCatalog.scala
+++ b/sql/hive/src/main/scala/org/apache/spark/sql/hive/HiveExternalCatalog.scala
@@ -465,7 +465,7 @@ private[spark] class HiveExternalCatalog(conf: SparkConf, hadoopConf: Configurat
     // will be updated automatically in Hive metastore by the `alterTable` call at the end of this
     // method. Here we only update the path option if the path option already exists in storage
     // properties, to avoid adding a unnecessary path option for Hive serde tables.
-    val hasPathOption = new CaseInsensitiveMap(rawTable.storage.properties).contains("path")
+    val hasPathOption = CaseInsensitiveMap(rawTable.storage.properties).contains("path")
     val storageWithNewPath = if (rawTable.tableType == MANAGED && hasPathOption) {
       // If it's a managed table with path option and we are renaming it, then the path option
       // becomes inaccurate and we need to update it according to the new table name.
@@ -483,7 +483,7 @@ private[spark] class HiveExternalCatalog(conf: SparkConf, hadoopConf: Configurat
   }
 
   private def getLocationFromStorageProps(table: CatalogTable): Option[String] = {
-    new CaseInsensitiveMap(table.storage.properties).get("path")
+    CaseInsensitiveMap(table.storage.properties).get("path")
   }
 
   private def updateLocationInStorageProps(
diff --git a/sql/hive/src/main/scala/org/apache/spark/sql/hive/execution/HiveOptions.scala b/sql/hive/src/main/scala/org/apache/spark/sql/hive/execution/HiveOptions.scala
index 35b7a681f1..1928510280 100644
--- a/sql/hive/src/main/scala/org/apache/spark/sql/hive/execution/HiveOptions.scala
+++ b/sql/hive/src/main/scala/org/apache/spark/sql/hive/execution/HiveOptions.scala
@@ -23,10 +23,11 @@ import org.apache.spark.sql.catalyst.util.CaseInsensitiveMap
  * Options for the Hive data source. Note that rule `DetermineHiveSerde` will extract Hive
  * serde/format information from these options.
  */
-class HiveOptions(@transient private val parameters: CaseInsensitiveMap) extends Serializable {
+class HiveOptions(@transient private val parameters: CaseInsensitiveMap[String])
+  extends Serializable {
   import HiveOptions._
 
-  def this(parameters: Map[String, String]) = this(new CaseInsensitiveMap(parameters))
+  def this(parameters: Map[String, String]) = this(CaseInsensitiveMap(parameters))
 
   val fileFormat = parameters.get(FILE_FORMAT).map(_.toLowerCase)
   val inputFormat = parameters.get(INPUT_FORMAT)
diff --git a/sql/hive/src/main/scala/org/apache/spark/sql/hive/orc/OrcOptions.scala b/sql/hive/src/main/scala/org/apache/spark/sql/hive/orc/OrcOptions.scala
index ac587ab99a..ccaa568dcc 100644
--- a/sql/hive/src/main/scala/org/apache/spark/sql/hive/orc/OrcOptions.scala
+++ b/sql/hive/src/main/scala/org/apache/spark/sql/hive/orc/OrcOptions.scala
@@ -22,12 +22,12 @@ import org.apache.spark.sql.catalyst.util.CaseInsensitiveMap
 /**
  * Options for the ORC data source.
  */
-private[orc] class OrcOptions(@transient private val parameters: CaseInsensitiveMap)
+private[orc] class OrcOptions(@transient private val parameters: CaseInsensitiveMap[String])
   extends Serializable {
 
   import OrcOptions._
 
-  def this(parameters: Map[String, String]) = this(new CaseInsensitiveMap(parameters))
+  def this(parameters: Map[String, String]) = this(CaseInsensitiveMap(parameters))
 
   /**
    * Compression codec to use. By default snappy compression.