[SPARK-11455][SQL] fix case sensitivity of partition by

depend on `caseSensitive` to do column name equality check, instead of just `==`

Author: Wenchen Fan <wenchen@databricks.com>

Closes #9410 from cloud-fan/partition.

sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/PartitioningUtils.scala

@@ -287,10 +287,11 @@ private[sql] object PartitioningUtils {
 
   def validatePartitionColumnDataTypes(
       schema: StructType,
-      partitionColumns: Array[String]): Unit = {
+      partitionColumns: Array[String],
+      caseSensitive: Boolean): Unit = {
 
-    ResolvedDataSource.partitionColumnsSchema(schema, partitionColumns).foreach { field =>
-      field.dataType match {
+    ResolvedDataSource.partitionColumnsSchema(schema, partitionColumns, caseSensitive).foreach {
+      field => field.dataType match {
         case _: AtomicType => // OK
         case _ => throw new AnalysisException(s"Cannot use ${field.dataType} for partition column")
       }

sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/ResolvedDataSource.scala

@@ -99,7 +99,8 @@ object ResolvedDataSource extends Logging {
           val maybePartitionsSchema = if (partitionColumns.isEmpty) {
             None
           } else {
-            Some(partitionColumnsSchema(schema, partitionColumns))
+            Some(partitionColumnsSchema(
+              schema, partitionColumns, sqlContext.conf.caseSensitiveAnalysis))
           }
 
           val caseInsensitiveOptions = new CaseInsensitiveMap(options)
@@ -172,14 +173,24 @@ object ResolvedDataSource extends Logging {
 
   def partitionColumnsSchema(
       schema: StructType,
-      partitionColumns: Array[String]): StructType = {
+      partitionColumns: Array[String],
+      caseSensitive: Boolean): StructType = {
+    val equality = columnNameEquality(caseSensitive)
     StructType(partitionColumns.map { col =>
-      schema.find(_.name == col).getOrElse {
+      schema.find(f => equality(f.name, col)).getOrElse {
         throw new RuntimeException(s"Partition column $col not found in schema $schema")
       }
     }).asNullable
   }
 
+  private def columnNameEquality(caseSensitive: Boolean): (String, String) => Boolean = {
+    if (caseSensitive) {
+      org.apache.spark.sql.catalyst.analysis.caseSensitiveResolution
+    } else {
+      org.apache.spark.sql.catalyst.analysis.caseInsensitiveResolution
+    }
+  }
+
   /** Create a [[ResolvedDataSource]] for saving the content of the given DataFrame. */
   def apply(
       sqlContext: SQLContext,
@@ -207,14 +218,18 @@ object ResolvedDataSource extends Logging {
           path.makeQualified(fs.getUri, fs.getWorkingDirectory)
         }
 
-        PartitioningUtils.validatePartitionColumnDataTypes(data.schema, partitionColumns)
+        val caseSensitive = sqlContext.conf.caseSensitiveAnalysis
+        PartitioningUtils.validatePartitionColumnDataTypes(
+          data.schema, partitionColumns, caseSensitive)
 
-        val dataSchema = StructType(data.schema.filterNot(f => partitionColumns.contains(f.name)))
+        val equality = columnNameEquality(caseSensitive)
+        val dataSchema = StructType(
+          data.schema.filterNot(f => partitionColumns.exists(equality(_, f.name))))
         val r = dataSource.createRelation(
           sqlContext,
           Array(outputPath.toString),
           Some(dataSchema.asNullable),
-          Some(partitionColumnsSchema(data.schema, partitionColumns)),
+          Some(partitionColumnsSchema(data.schema, partitionColumns, caseSensitive)),
           caseInsensitiveOptions)
 
         // For partitioned relation r, r.schema's column ordering can be different from the column

sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/rules.scala

@@ -140,7 +140,8 @@ private[sql] case class PreWriteCheck(catalog: Catalog) extends (LogicalPlan =>
           // OK
         }
 
-        PartitioningUtils.validatePartitionColumnDataTypes(r.schema, part.keySet.toArray)
+        PartitioningUtils.validatePartitionColumnDataTypes(
+          r.schema, part.keySet.toArray, catalog.conf.caseSensitiveAnalysis)
 
         // Get all input data source relations of the query.
         val srcRelations = query.collect {
@@ -190,7 +191,8 @@ private[sql] case class PreWriteCheck(catalog: Catalog) extends (LogicalPlan =>
           // OK
         }
 
-        PartitioningUtils.validatePartitionColumnDataTypes(query.schema, partitionColumns)
+        PartitioningUtils.validatePartitionColumnDataTypes(
+          query.schema, partitionColumns, catalog.conf.caseSensitiveAnalysis)
 
       case _ => // OK
     }

sql/core/src/test/scala/org/apache/spark/sql/DataFrameSuite.scala

@@ -1118,4 +1118,14 @@ class DataFrameSuite extends QueryTest with SharedSQLContext {
       if (!allSequential) throw new SparkException("Partition should contain all sequential values")
     })
   }
+
+  test("fix case sensitivity of partition by") {
+    withSQLConf(SQLConf.CASE_SENSITIVE.key -> "false") {
+      withTempPath { path =>
+        val p = path.getAbsolutePath
+        Seq(2012 -> "a").toDF("year", "val").write.partitionBy("yEAr").parquet(p)
+        checkAnswer(sqlContext.read.parquet(p).select("YeaR"), Row(2012))
+      }
+    }
+  }
 }