[SPARK-18333][SQL] Revert hacks in parquet and orc reader to support case insensitive resolution

## What changes were proposed in this pull request?

These are no longer needed after https://issues.apache.org/jira/browse/SPARK-17183

cc cloud-fan

## How was this patch tested?

Existing parquet and orc tests.

Author: Eric Liang <ekl@databricks.com>

Closes #15799 from ericl/sc-4929.

1 files changed, 1 insertions, 11 deletions

diff --git a/sql/hive/src/main/scala/org/apache/spark/sql/hive/orc/OrcFileFormat.scala b/sql/hive/src/main/scala/org/apache/spark/sql/hive/orc/OrcFileFormat.scala
index 7c519a0743..42c92ed5ca 100644
--- a/sql/hive/src/main/scala/org/apache/spark/sql/hive/orc/OrcFileFormat.scala
+++ b/sql/hive/src/main/scala/org/apache/spark/sql/hive/orc/OrcFileFormat.scala
@@ -305,17 +305,7 @@ private[orc] object OrcRelation extends HiveInspectors {
 
   def setRequiredColumns(
       conf: Configuration, physicalSchema: StructType, requestedSchema: StructType): Unit = {
-    val caseInsensitiveFieldMap: Map[String, Int] = physicalSchema.fieldNames
-      .zipWithIndex
-      .map(f => (f._1.toLowerCase, f._2))
-      .toMap
-    val ids = requestedSchema.map { a =>
-      val exactMatch: Option[Int] = physicalSchema.getFieldIndex(a.name)
-      val res = exactMatch.getOrElse(
-        caseInsensitiveFieldMap.getOrElse(a.name,
-          throw new IllegalArgumentException(s"""Field "$a.name" does not exist.""")))
-      res: Integer
-    }
+    val ids = requestedSchema.map(a => physicalSchema.fieldIndex(a.name): Integer)
     val (sortedIDs, sortedNames) = ids.zip(requestedSchema.fieldNames).sorted.unzip
     HiveShim.appendReadColumns(conf, sortedIDs, sortedNames)
   }