Disable use of KryoSerializer in Thrift Server

Author: JoshRosen

docs/configuration.md

@@ -744,7 +744,7 @@ Apart from these, the following properties are also available, and may be useful
 </tr>
 <tr>
   <td><code>spark.kryo.referenceTracking</code></td>
-  <td>true (false when using Spark SQL Thrift Server)</td>
+  <td>true</td>
   <td>
     Whether to track references to the same object when serializing data with Kryo, which is
     necessary if your object graphs have loops and useful for efficiency if they contain multiple
@@ -807,8 +807,7 @@ Apart from these, the following properties are also available, and may be useful
 <tr>
   <td><code>spark.serializer</code></td>
   <td>
-    org.apache.spark.serializer.<br />JavaSerializer (org.apache.spark.serializer.<br />
-    KryoSerializer when using Spark SQL Thrift Server)
+    org.apache.spark.serializer.<br />JavaSerializer
   </td>
   <td>
     Class to use for serializing objects that will be sent over the network or need to be cached

sql/hive-thriftserver/src/main/scala/org/apache/spark/sql/hive/thriftserver/SparkSQLEnv.scala

@@ -19,8 +19,6 @@ package org.apache.spark.sql.hive.thriftserver
 
 import java.io.PrintStream
 
-import scala.collection.JavaConverters._
-
 import org.apache.spark.{SparkConf, SparkContext}
 import org.apache.spark.internal.Logging
 import org.apache.spark.sql.{SparkSession, SQLContext}
@@ -37,8 +35,6 @@ private[hive] object SparkSQLEnv extends Logging {
   def init() {
     if (sqlContext == null) {
       val sparkConf = new SparkConf(loadDefaults = true)
-      val maybeSerializer = sparkConf.getOption("spark.serializer")
-      val maybeKryoReferenceTracking = sparkConf.getOption("spark.kryo.referenceTracking")
       // If user doesn't specify the appName, we want to get [SparkSQL::localHostName] instead of
       // the default appName [SparkSQLCLIDriver] in cli or beeline.
       val maybeAppName = sparkConf
@@ -47,12 +43,6 @@ private[hive] object SparkSQLEnv extends Logging {
 
       sparkConf
         .setAppName(maybeAppName.getOrElse(s"SparkSQL::${Utils.localHostName()}"))
-        .set(
-          "spark.serializer",
-          maybeSerializer.getOrElse("org.apache.spark.serializer.KryoSerializer"))
-        .set(
-          "spark.kryo.referenceTracking",
-          maybeKryoReferenceTracking.getOrElse("false"))
 
       val sparkSession = SparkSession.builder.config(sparkConf).enableHiveSupport().getOrCreate()
       sparkContext = sparkSession.sparkContext