[SPARK-2087] [SQL] Multiple thriftserver sessions with single HiveContext instance

Still, we keep only a single HiveContext within ThriftServer, and we also create a object called `SQLSession` for isolating the different user states.

Developers can obtain/release a new user session via `openSession` and `closeSession`, and `SQLContext` and `HiveContext` will also provide a default session if no `openSession` called, for backward-compatibility.

Author: Cheng Hao <hao.cheng@intel.com>

Closes #4885 from chenghao-intel/multisessions_singlecontext and squashes the following commits:

1c47b2a [Cheng Hao] rename the tss => tlSession
815b27a [Cheng Hao] code style issue
57e3fa0 [Cheng Hao] openSession is not compatible between Hive0.12 & 0.13.1
4665b0d [Cheng Hao] thriftservice with single context

1 files changed, 0 insertions, 56 deletions

diff --git a/sql/hive-thriftserver/src/main/scala/org/apache/spark/sql/hive/thriftserver/SparkSQLSessionManager.scala b/sql/hive-thriftserver/src/main/scala/org/apache/spark/sql/hive/thriftserver/SparkSQLSessionManager.scala
deleted file mode 100644
index 89e9ede726..0000000000
--- a/sql/hive-thriftserver/src/main/scala/org/apache/spark/sql/hive/thriftserver/SparkSQLSessionManager.scala
+++ /dev/null
@@ -1,56 +0,0 @@
-/*
- * 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.thriftserver
-
-import java.util.concurrent.Executors
-
-import org.apache.commons.logging.Log
-import org.apache.hadoop.hive.conf.HiveConf
-import org.apache.hadoop.hive.conf.HiveConf.ConfVars
-import org.apache.hive.service.cli.session.SessionManager
-
-import org.apache.spark.sql.hive.HiveContext
-import org.apache.spark.sql.hive.thriftserver.ReflectionUtils._
-import org.apache.spark.sql.hive.thriftserver.server.SparkSQLOperationManager
-import org.apache.hive.service.cli.SessionHandle
-
-private[hive] class SparkSQLSessionManager(hiveContext: HiveContext)
-  extends SessionManager
-  with ReflectedCompositeService {
-
-  private lazy val sparkSqlOperationManager = new SparkSQLOperationManager(hiveContext)
-
-  override def init(hiveConf: HiveConf) {
-    setSuperField(this, "hiveConf", hiveConf)
-
-    val backgroundPoolSize = hiveConf.getIntVar(ConfVars.HIVE_SERVER2_ASYNC_EXEC_THREADS)
-    setSuperField(this, "backgroundOperationPool", Executors.newFixedThreadPool(backgroundPoolSize))
-    getAncestorField[Log](this, 3, "LOG").info(
-      s"HiveServer2: Async execution pool size $backgroundPoolSize")
-
-    setSuperField(this, "operationManager", sparkSqlOperationManager)
-    addService(sparkSqlOperationManager)
-
-    initCompositeService(hiveConf)
-  }
-
-  override def closeSession(sessionHandle: SessionHandle) {
-    super.closeSession(sessionHandle)
-    sparkSqlOperationManager.sessionToActivePool -= sessionHandle
-  }
-}