Github user marmbrus commented on a diff in the pull request:
https://github.com/apache/spark/pull/12485#discussion_r60314954
--- Diff: sql/core/src/main/scala/org/apache/spark/sql/SparkSession.scala
---
@@ -0,0 +1,100 @@
+/*
+ * 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
+
+import scala.reflect.ClassTag
+import scala.util.control.NonFatal
+
+import org.apache.spark.{SparkConf, SparkContext}
+import org.apache.spark.internal.config.CATALOG_IMPLEMENTATION
+import org.apache.spark.sql.internal.{SessionState, SharedState}
+import org.apache.spark.util.Utils
+
+
+/**
+ * The entry point to Spark execution.
+ */
+class SparkSession private(
+ sparkContext: SparkContext,
+ existingSharedState: Option[SharedState]) { self =>
+
+ def this(sc: SparkContext) {
+ this(sc, None)
+ }
+
+ /**
+ * Start a new session where configurations, temp tables, temp functions
etc. are isolated.
+ */
+ def newSession(): SparkSession = {
+ // Note: materialize the shared state here to ensure the parent and
child sessions are
+ // initialized with the same shared state.
+ new SparkSession(sparkContext, Some(sharedState))
+ }
+
+ @transient
+ protected[sql] lazy val sharedState: SharedState = {
+ existingSharedState.getOrElse(
+ SparkSession.reflect[SharedState, SparkContext](
+ SparkSession.sharedStateClassName(sparkContext.conf),
+ sparkContext))
+ }
+
+ @transient
+ protected[sql] lazy val sessionState: SessionState = {
+ SparkSession.reflect[SessionState, SQLContext](
+ SparkSession.sessionStateClassName(sparkContext.conf),
+ new SQLContext(self, isRootContext = false))
+ }
+
+}
+
+
+private object SparkSession {
+
+ private def sharedStateClassName(conf: SparkConf): String = {
+ conf.get(CATALOG_IMPLEMENTATION) match {
+ case "hive" => "org.apache.spark.sql.hive.HiveSharedState"
+ case "in-memory" => classOf[SharedState].getCanonicalName
+ }
+ }
+
+ private def sessionStateClassName(conf: SparkConf): String = {
+ conf.get(CATALOG_IMPLEMENTATION) match {
+ case "hive" => "org.apache.spark.sql.hive.HiveSessionState"
+ case "in-memory" => classOf[SessionState].getCanonicalName
+ }
+ }
+
+ /**
+ * Helper method to create an instance of [[T]] using a single-arg
constructor that
+ * accepts an [[Arg]].
+ */
+ private def reflect[T, Arg <: AnyRef](
+ className: String,
+ ctorArg: Arg)(implicit ctorArgTag: ClassTag[Arg]): T = {
--- End diff --
You don't need a class tag. You can call `ctorArg.getClass()`.
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at [email protected] or file a JIRA ticket
with INFRA.
---
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
