From dec978d5931ba6e6645bb1eb585195c6c49b842a Mon Sep 17 00:00:00 2001
From: CodeGod <>
Date: Thu, 7 Mar 2019 13:22:44 +0800
Subject: [PATCH] bug fix: mergeWithMetastoreSchema with Uuniform lower case
 comparison

(cherry picked from commit f47a765)
---
 .../spark/sql/hive/HiveMetastoreCatalog.scala |  2 +-
 .../sql/hive/HiveSchemaInferenceSuite.scala   | 26 +++++++++++++++++++
 2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/sql/hive/src/main/scala/org/apache/spark/sql/hive/HiveMetastoreCatalog.scala b/sql/hive/src/main/scala/org/apache/spark/sql/hive/HiveMetastoreCatalog.scala
index 03f4b8d83e353..d6b2945b2ea7a 100644
--- a/sql/hive/src/main/scala/org/apache/spark/sql/hive/HiveMetastoreCatalog.scala
+++ b/sql/hive/src/main/scala/org/apache/spark/sql/hive/HiveMetastoreCatalog.scala
@@ -326,8 +326,8 @@ private[hive] object HiveMetastoreCatalog {
     // Merge missing nullable fields to inferred schema and build a case-insensitive field map.
     val inferredFields = StructType(inferredSchema ++ missingNullables)
       .map(f => f.name.toLowerCase -> f).toMap
+    StructType(metastoreSchema.map(f => f.copy(name = inferredFields(f.name.toLowerCase).name)))
     // scalastyle:on caselocale
-    StructType(metastoreSchema.map(f => f.copy(name = inferredFields(f.name).name)))
   } catch {
     case NonFatal(_) =>
       val msg = s"""Detected conflicting schemas when merging the schema obtained from the Hive
diff --git a/sql/hive/src/test/scala/org/apache/spark/sql/hive/HiveSchemaInferenceSuite.scala b/sql/hive/src/test/scala/org/apache/spark/sql/hive/HiveSchemaInferenceSuite.scala
index aa4fc13333c48..590ef949ffbd7 100644
--- a/sql/hive/src/test/scala/org/apache/spark/sql/hive/HiveSchemaInferenceSuite.scala
+++ b/sql/hive/src/test/scala/org/apache/spark/sql/hive/HiveSchemaInferenceSuite.scala
@@ -264,6 +264,32 @@ class HiveSchemaInferenceSuite
         StructType(Seq(StructField("lowerCase", BinaryType))))
     }
 
+    // Parquet schema is subset of metaStore schema and has uppercase field name
+    assertResult(
+      StructType(Seq(
+        StructField("UPPERCase", DoubleType, nullable = true),
+        StructField("lowerCase", BinaryType, nullable = true)))) {
+
+      HiveMetastoreCatalog.mergeWithMetastoreSchema(
+        StructType(Seq(
+          StructField("UPPERCase", DoubleType, nullable = true),
+          StructField("lowerCase", BinaryType, nullable = true))),
+
+        StructType(Seq(
+          StructField("lowerCase", BinaryType, nullable = true))))
+    }
+
+    // Metastore schema contains additional nullable fields.
+    assert(intercept[Throwable] {
+      HiveMetastoreCatalog.mergeWithMetastoreSchema(
+        StructType(Seq(
+          StructField("UPPERCase", DoubleType, nullable = false),
+          StructField("lowerCase", BinaryType, nullable = true))),
+
+        StructType(Seq(
+          StructField("lowerCase", BinaryType, nullable = true))))
+    }.getMessage.contains("Detected conflicting schemas"))
+
     // Check that merging missing nullable fields works as expected.
     assertResult(
       StructType(Seq(