[SPARK-18121][SQL] Unable to query global temp views when hive support is enabled

## What changes were proposed in this pull request?

Issue:
Querying on a global temp view throws Table or view not found exception.

Fix:
Update the lookupRelation in HiveSessionCatalog to check for global temp views similar to the SessionCatalog.lookupRelation.

Before fix:
Querying on a global temp view ( for. e.g.:  select * from global_temp.v1)  throws Table or view not found exception

After fix:
Query succeeds and returns the right result.

## How was this patch tested?
- Two unit tests are added to check for global temp view for the code path when hive support is enabled.
- Regression unit tests were run successfully. ( build/sbt -Phive hive/test, build/sbt sql/test, build/sbt catalyst/test)

Author: Sunitha Kambhampati <skambha@us.ibm.com>

Closes #15649 from skambha/lookuprelationChanges.

sql/hive/src/main/scala/org/apache/spark/sql/hive/HiveSessionCatalog.scala

@@ -27,7 +27,7 @@ import org.apache.hadoop.hive.ql.udf.generic.{AbstractGenericUDAFResolver, Gener
 
 import org.apache.spark.sql.{AnalysisException, SparkSession}
 import org.apache.spark.sql.catalyst.{FunctionIdentifier, TableIdentifier}
-import org.apache.spark.sql.catalyst.analysis.FunctionRegistry
+import org.apache.spark.sql.catalyst.analysis.{FunctionRegistry, NoSuchTableException}
 import org.apache.spark.sql.catalyst.analysis.FunctionRegistry.FunctionBuilder
 import org.apache.spark.sql.catalyst.catalog.{FunctionResourceLoader, GlobalTempViewManager, SessionCatalog}
 import org.apache.spark.sql.catalyst.expressions.{Cast, Expression, ExpressionInfo}
@@ -57,7 +57,13 @@ private[sql] class HiveSessionCatalog(
 
   override def lookupRelation(name: TableIdentifier, alias: Option[String]): LogicalPlan = {
     val table = formatTableName(name.table)
-    if (name.database.isDefined || !tempTables.contains(table)) {
+    val db = formatDatabaseName(name.database.getOrElse(currentDb))
+    if (db == globalTempViewManager.database) {
+      val relationAlias = alias.getOrElse(table)
+      globalTempViewManager.get(table).map { viewDef =>
+        SubqueryAlias(relationAlias, viewDef, Some(name))
+      }.getOrElse(throw new NoSuchTableException(db, table))
+    } else if (name.database.isDefined || !tempTables.contains(table)) {
       val database = name.database.map(formatDatabaseName)
       val newName = name.copy(database = database, table = table)
       metastoreCatalog.lookupRelation(newName, alias)

sql/hive/src/test/scala/org/apache/spark/sql/hive/execution/SQLQuerySuite.scala

@@ -68,6 +68,22 @@ class SQLQuerySuite extends QueryTest with SQLTestUtils with TestHiveSingleton {
   import hiveContext._
   import spark.implicits._
 
+  test("query global temp view") {
+    val df = Seq(1).toDF("i1")
+    df.createGlobalTempView("tbl1")
+    val global_temp_db = spark.conf.get("spark.sql.globalTempDatabase")
+    checkAnswer(spark.sql(s"select * from ${global_temp_db}.tbl1"), Row(1))
+    spark.sql(s"drop view ${global_temp_db}.tbl1")
+  }
+
+  test("non-existent global temp view") {
+    val global_temp_db = spark.conf.get("spark.sql.globalTempDatabase")
+    val message = intercept[AnalysisException] {
+      spark.sql(s"select * from ${global_temp_db}.nonexistentview")
+    }.getMessage
+    assert(message.contains("Table or view not found"))
+  }
+
   test("script") {
     val scriptFilePath = getTestResourcePath("test_script.sh")
     if (testCommandAvailable("bash") && testCommandAvailable("echo | sed")) {