[SPARK-14647][SQL] Group SQLContext/HiveContext state into SharedState

sql/core/src/main/scala/org/apache/spark/sql/SQLContext.scala

@@ -41,7 +41,7 @@ import org.apache.spark.sql.execution._
 import org.apache.spark.sql.execution.command.ShowTablesCommand
 import org.apache.spark.sql.execution.datasources._
 import org.apache.spark.sql.execution.ui.{SQLListener, SQLTab}
-import org.apache.spark.sql.internal.{SessionState, SQLConf}
+import org.apache.spark.sql.internal.{SessionState, SharedState, SQLConf}
 import org.apache.spark.sql.sources.BaseRelation
 import org.apache.spark.sql.types._
 import org.apache.spark.sql.util.ExecutionListenerManager
@@ -63,17 +63,14 @@ import org.apache.spark.util.Utils
  * @since 1.0.0
  */
 class SQLContext private[sql](
-    @transient val sparkContext: SparkContext,
-    @transient protected[sql] val cacheManager: CacheManager,
-    @transient private[sql] val listener: SQLListener,
-    val isRootContext: Boolean,
-    @transient private[sql] val externalCatalog: ExternalCatalog)
+    @transient protected[sql] val sharedState: SharedState,
+    val isRootContext: Boolean)
   extends Logging with Serializable {
 
   self =>
 
   def this(sc: SparkContext) = {
-    this(sc, new CacheManager, SQLContext.createListenerAndUI(sc), true, new InMemoryCatalog)
+    this(new SharedState(sc), true)
   }
 
   def this(sparkContext: JavaSparkContext) = this(sparkContext.sc)
@@ -100,20 +97,20 @@ class SQLContext private[sql](
     }
   }
 
+  def sparkContext: SparkContext = sharedState.sparkContext
+
+  protected[sql] def cacheManager: CacheManager = sharedState.cacheManager
+  protected[sql] def listener: SQLListener = sharedState.listener
+  protected[sql] def externalCatalog: ExternalCatalog = sharedState.externalCatalog
+
   /**
-   * Returns a SQLContext as new session, with separated SQL configurations, temporary tables,
-   * registered functions, but sharing the same SparkContext, CacheManager, SQLListener and SQLTab.
+   * Returns a [[SQLContext]] as new session, with separated SQL configurations, temporary
+   * tables, registered functions, but sharing the same [[SparkContext]], cached data and
+   * other things.
    *
    * @since 1.6.0
    */
-  def newSession(): SQLContext = {
-    new SQLContext(
-      sparkContext = sparkContext,
-      cacheManager = cacheManager,
-      listener = listener,
-      isRootContext = false,
-      externalCatalog = externalCatalog)
-  }
+  def newSession(): SQLContext = new SQLContext(sharedState, isRootContext = false)
 
   /**
    * Per-session state, e.g. configuration, functions, temporary tables etc.

sql/core/src/main/scala/org/apache/spark/sql/internal/SessionState.scala

@@ -22,10 +22,8 @@ import org.apache.spark.sql.catalyst.analysis.{Analyzer, FunctionRegistry}
 import org.apache.spark.sql.catalyst.catalog.SessionCatalog
 import org.apache.spark.sql.catalyst.optimizer.Optimizer
 import org.apache.spark.sql.catalyst.parser.ParserInterface
-import org.apache.spark.sql.catalyst.rules.RuleExecutor
 import org.apache.spark.sql.execution._
 import org.apache.spark.sql.execution.datasources.{DataSourceAnalysis, PreInsertCastAndRename, ResolveDataSource}
-import org.apache.spark.sql.execution.exchange.{EnsureRequirements, ReuseExchange}
 import org.apache.spark.sql.util.ExecutionListenerManager
 
 /**

sql/core/src/main/scala/org/apache/spark/sql/internal/SharedState.scala

@@ -0,0 +1,47 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.spark.sql.internal
+
+import org.apache.spark.SparkContext
+import org.apache.spark.sql.SQLContext
+import org.apache.spark.sql.catalyst.catalog.{ExternalCatalog, InMemoryCatalog}
+import org.apache.spark.sql.execution.CacheManager
+import org.apache.spark.sql.execution.ui.SQLListener
+
+
+/**
+ * A class that holds all state shared across sessions in a given [[SQLContext]].
+ */
+private[sql] class SharedState(val sparkContext: SparkContext) {
+
+  /**
+   * Class for caching query results reused in future executions.
+   */
+  val cacheManager: CacheManager = new CacheManager
+
+  /**
+   * A listener for SQL-specific [[org.apache.spark.scheduler.SparkListenerEvent]]s.
+   */
+  val listener: SQLListener = SQLContext.createListenerAndUI(sparkContext)
+
+  /**
+   * A catalog that interacts with external systems.
+   */
+  lazy val externalCatalog: ExternalCatalog = new InMemoryCatalog
+
+}

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

@@ -45,12 +45,10 @@ import org.apache.spark.sql.catalyst.InternalRow
 import org.apache.spark.sql.catalyst.expressions.{Expression, LeafExpression}
 import org.apache.spark.sql.catalyst.expressions.codegen.CodegenFallback
 import org.apache.spark.sql.catalyst.plans.logical._
-import org.apache.spark.sql.execution._
 import org.apache.spark.sql.execution.command.{ExecutedCommand, SetCommand}
-import org.apache.spark.sql.execution.ui.SQLListener
 import org.apache.spark.sql.hive.client._
 import org.apache.spark.sql.hive.execution.{AnalyzeTable, DescribeHiveTableCommand, HiveNativeCommand}
-import org.apache.spark.sql.internal.SQLConf
+import org.apache.spark.sql.internal.{SharedState, SQLConf}
 import org.apache.spark.sql.internal.SQLConf._
 import org.apache.spark.sql.types._
 import org.apache.spark.unsafe.types.UTF8String
@@ -63,32 +61,14 @@ import org.apache.spark.util.Utils
  * @since 1.0.0
  */
 class HiveContext private[hive](
-    sc: SparkContext,
-    cacheManager: CacheManager,
-    listener: SQLListener,
-    @transient private[hive] val executionHive: HiveClientImpl,
-    @transient private[hive] val metadataHive: HiveClient,
-    isRootContext: Boolean,
-    @transient private[sql] val hiveCatalog: HiveExternalCatalog)
-  extends SQLContext(sc, cacheManager, listener, isRootContext, hiveCatalog) with Logging {
-  self =>
+    @transient protected[hive] val hiveSharedState: HiveSharedState,
+    override val isRootContext: Boolean)
+  extends SQLContext(hiveSharedState, isRootContext) with Logging {
 
-  private def this(sc: SparkContext, execHive: HiveClientImpl, metaHive: HiveClient) {
-    this(
-      sc,
-      new CacheManager,
-      SQLContext.createListenerAndUI(sc),
-      execHive,
-      metaHive,
-      true,
-      new HiveExternalCatalog(metaHive))
-  }
+  self =>
 
   def this(sc: SparkContext) = {
-    this(
-      sc,
-      HiveContext.newClientForExecution(sc.conf, sc.hadoopConfiguration),
-      HiveContext.newClientForMetadata(sc.conf, sc.hadoopConfiguration))
+    this(new HiveSharedState(sc), true)
   }
 
   def this(sc: JavaSparkContext) = this(sc.sc)
@@ -103,19 +83,16 @@ class HiveContext private[hive](
    * and Hive client (both of execution and metadata) with existing HiveContext.
    */
   override def newSession(): HiveContext = {
-    new HiveContext(
-      sc = sc,
-      cacheManager = cacheManager,
-      listener = listener,
-      executionHive = executionHive.newSession(),
-      metadataHive = metadataHive.newSession(),
-      isRootContext = false,
-      hiveCatalog = hiveCatalog)
+    new HiveContext(hiveSharedState, isRootContext = false)
   }
 
   @transient
   protected[sql] override lazy val sessionState = new HiveSessionState(self)
 
+  protected[hive] def hiveCatalog: HiveExternalCatalog = hiveSharedState.externalCatalog
+  protected[hive] def executionHive: HiveClientImpl = sessionState.executionHive
+  protected[hive] def metadataHive: HiveClient = sessionState.metadataHive
+
   /**
    * When true, enables an experimental feature where metastore tables that use the parquet SerDe
    * are automatically converted to use the Spark SQL parquet table scan, instead of the Hive
@@ -159,7 +136,7 @@ class HiveContext private[hive](
   protected[hive] def hiveThriftServerAsync: Boolean = getConf(HIVE_THRIFT_SERVER_ASYNC)
 
   protected[hive] def hiveThriftServerSingleSession: Boolean =
-    sc.conf.get("spark.sql.hive.thriftServer.singleSession", "false").toBoolean
+    sparkContext.conf.getBoolean("spark.sql.hive.thriftServer.singleSession", defaultValue = false)
 
   @transient
   protected[sql] lazy val substitutor = new VariableSubstitution()
@@ -527,7 +504,9 @@ private[hive] object HiveContext extends Logging {
    * The version of the Hive client that is used here must match the metastore that is configured
    * in the hive-site.xml file.
    */
-  private def newClientForMetadata(conf: SparkConf, hadoopConf: Configuration): HiveClient = {
+  protected[hive] def newClientForMetadata(
+      conf: SparkConf,
+      hadoopConf: Configuration): HiveClient = {
     val hiveConf = new HiveConf(hadoopConf, classOf[HiveConf])
     val configurations = hiveClientConfigurations(hiveConf)
     newClientForMetadata(conf, hiveConf, hadoopConf, configurations)

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

@@ -18,10 +18,11 @@
 package org.apache.spark.sql.hive
 
 import org.apache.spark.sql._
-import org.apache.spark.sql.catalyst.analysis.{Analyzer, FunctionRegistry}
+import org.apache.spark.sql.catalyst.analysis.Analyzer
 import org.apache.spark.sql.catalyst.parser.ParserInterface
-import org.apache.spark.sql.execution.{python, SparkPlanner}
+import org.apache.spark.sql.execution.SparkPlanner
 import org.apache.spark.sql.execution.datasources._
+import org.apache.spark.sql.hive.client.{HiveClient, HiveClientImpl}
 import org.apache.spark.sql.hive.execution.HiveSqlParser
 import org.apache.spark.sql.internal.{SessionState, SQLConf}
 
@@ -31,6 +32,16 @@ import org.apache.spark.sql.internal.{SessionState, SQLConf}
  */
 private[hive] class HiveSessionState(ctx: HiveContext) extends SessionState(ctx) {
 
+  /**
+   * A Hive client used for execution.
+   */
+  val executionHive: HiveClientImpl = ctx.hiveSharedState.executionHive.newSession()
+
+  /**
+   * A Hive client used for interacting with the metastore.
+   */
+  val metadataHive: HiveClient = ctx.hiveSharedState.metadataHive.newSession()
+
   override lazy val conf: SQLConf = new SQLConf {
     override def caseSensitiveAnalysis: Boolean = getConf(SQLConf.CASE_SENSITIVE, false)
   }

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

@@ -0,0 +1,53 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.spark.sql.hive
+
+import org.apache.spark.SparkContext
+import org.apache.spark.sql.hive.client.{HiveClient, HiveClientImpl}
+import org.apache.spark.sql.internal.SharedState
+
+
+/**
+ * A class that holds all state shared across sessions in a given [[HiveContext]].
+ */
+private[hive] class HiveSharedState(override val sparkContext: SparkContext)
+  extends SharedState(sparkContext) {
+
+  // TODO: just share the IsolatedClientLoader instead of the client instances themselves
+
+  /**
+   * A Hive client used for execution.
+   */
+  val executionHive: HiveClientImpl = {
+    HiveContext.newClientForExecution(sparkContext.conf, sparkContext.hadoopConfiguration)
+  }
+
+  /**
+   * A Hive client used to interact with the metastore.
+   */
+  // This needs to be a lazy val at here because TestHiveSharedState is overriding it.
+  lazy val metadataHive: HiveClient = {
+    HiveContext.newClientForMetadata(sparkContext.conf, sparkContext.hadoopConfiguration)
+  }
+
+  /**
+   * A catalog that interacts with the Hive metastore.
+   */
+  override lazy val externalCatalog = new HiveExternalCatalog(metadataHive)
+
+}