[SPARK-19944][SQL] Move SQLConf from sql/core to sql/catalyst

## What changes were proposed in this pull request?
This patch moves SQLConf from sql/core to sql/catalyst. To minimize the changes, the patch used type alias to still keep CatalystConf (as a type alias) and SimpleCatalystConf (as a concrete class that extends SQLConf).

Motivation for the change is that it is pretty weird to have SQLConf only in sql/core and then we have to duplicate config options that impact optimizer/analyzer in sql/catalyst using CatalystConf.

## How was this patch tested?
N/A

Author: Reynold Xin <rxin@databricks.com>

Closes #17285 from rxin/SPARK-19944.

5 files changed, 165 insertions, 173 deletions

diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/CatalystConf.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/CatalystConf.scala
deleted file mode 100644
index cff0efa979..0000000000
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/CatalystConf.scala
+++ /dev/null
@@ -1,93 +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.catalyst
-
-import java.util.TimeZone
-
-import org.apache.spark.sql.catalyst.analysis._
-
-/**
- * Interface for configuration options used in the catalyst module.
- */
-trait CatalystConf {
-  def caseSensitiveAnalysis: Boolean
-
-  def orderByOrdinal: Boolean
-  def groupByOrdinal: Boolean
-
-  def optimizerMaxIterations: Int
-  def optimizerInSetConversionThreshold: Int
-  def maxCaseBranchesForCodegen: Int
-
-  def tableRelationCacheSize: Int
-
-  def runSQLonFile: Boolean
-
-  def warehousePath: String
-
-  def sessionLocalTimeZone: String
-
-  /** If true, cartesian products between relations will be allowed for all
-   * join types(inner, (left|right|full) outer).
-   * If false, cartesian products will require explicit CROSS JOIN syntax.
-   */
-  def crossJoinEnabled: Boolean
-
-  /**
-   * Returns the [[Resolver]] for the current configuration, which can be used to determine if two
-   * identifiers are equal.
-   */
-  def resolver: Resolver = {
-    if (caseSensitiveAnalysis) caseSensitiveResolution else caseInsensitiveResolution
-  }
-
-  /**
-   * Enables CBO for estimation of plan statistics when set true.
-   */
-  def cboEnabled: Boolean
-
-  /** Enables join reorder in CBO. */
-  def joinReorderEnabled: Boolean
-
-  /** The maximum number of joined nodes allowed in the dynamic programming algorithm. */
-  def joinReorderDPThreshold: Int
-
-  override def clone(): CatalystConf = throw new CloneNotSupportedException()
-}
-
-
-/** A CatalystConf that can be used for local testing. */
-case class SimpleCatalystConf(
-    caseSensitiveAnalysis: Boolean,
-    orderByOrdinal: Boolean = true,
-    groupByOrdinal: Boolean = true,
-    optimizerMaxIterations: Int = 100,
-    optimizerInSetConversionThreshold: Int = 10,
-    maxCaseBranchesForCodegen: Int = 20,
-    tableRelationCacheSize: Int = 1000,
-    runSQLonFile: Boolean = true,
-    crossJoinEnabled: Boolean = false,
-    cboEnabled: Boolean = false,
-    joinReorderEnabled: Boolean = false,
-    joinReorderDPThreshold: Int = 12,
-    warehousePath: String = "/user/hive/warehouse",
-    sessionLocalTimeZone: String = TimeZone.getDefault().getID)
-  extends CatalystConf {
-
-  override def clone(): SimpleCatalystConf = this.copy()
-}
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/SimpleCatalystConf.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/SimpleCatalystConf.scala
new file mode 100644
index 0000000000..746f84459d
--- /dev/null
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/SimpleCatalystConf.scala
@@ -0,0 +1,48 @@
+/*
+ * 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.catalyst
+
+import java.util.TimeZone
+
+import org.apache.spark.sql.internal.SQLConf
+
+
+/**
+ * A SQLConf that can be used for local testing. This class is only here to minimize the change
+ * for ticket SPARK-19944 (moves SQLConf from sql/core to sql/catalyst). This class should
+ * eventually be removed (test cases should just create SQLConf and set values appropriately).
+ */
+case class SimpleCatalystConf(
+    override val caseSensitiveAnalysis: Boolean,
+    override val orderByOrdinal: Boolean = true,
+    override val groupByOrdinal: Boolean = true,
+    override val optimizerMaxIterations: Int = 100,
+    override val optimizerInSetConversionThreshold: Int = 10,
+    override val maxCaseBranchesForCodegen: Int = 20,
+    override val tableRelationCacheSize: Int = 1000,
+    override val runSQLonFile: Boolean = true,
+    override val crossJoinEnabled: Boolean = false,
+    override val cboEnabled: Boolean = false,
+    override val joinReorderEnabled: Boolean = false,
+    override val joinReorderDPThreshold: Int = 12,
+    override val warehousePath: String = "/user/hive/warehouse",
+    override val sessionLocalTimeZone: String = TimeZone.getDefault().getID)
+  extends SQLConf {
+
+  override def clone(): SimpleCatalystConf = this.copy()
+}
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/package.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/package.scala
index 105cdf5250..4af56afebb 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/package.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/package.scala
@@ -17,6 +17,8 @@
 
 package org.apache.spark.sql
 
+import org.apache.spark.sql.internal.SQLConf
+
 /**
  * Catalyst is a library for manipulating relational query plans.  All classes in catalyst are
  * considered an internal API to Spark SQL and are subject to change between minor releases.
@@ -29,4 +31,9 @@ package object catalyst {
    */
   protected[sql] object ScalaReflectionLock
 
+  /**
+   * This class is only here to minimize the change for ticket SPARK-19944
+   * (moves SQLConf from sql/core to sql/catalyst). This class should eventually be removed.
+   */
+  type CatalystConf = SQLConf
 }
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/internal/SQLConf.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/internal/SQLConf.scala
index 8e3f567b7d..315bedb12e 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/internal/SQLConf.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/internal/SQLConf.scala
@@ -24,15 +24,11 @@ import scala.collection.JavaConverters._
 import scala.collection.immutable
 
 import org.apache.hadoop.fs.Path
-import org.apache.parquet.hadoop.ParquetOutputCommitter
 
 import org.apache.spark.internal.Logging
 import org.apache.spark.internal.config._
 import org.apache.spark.network.util.ByteUnit
-import org.apache.spark.sql.catalyst.CatalystConf
-import org.apache.spark.sql.execution.datasources.SQLHadoopMapReduceCommitProtocol
-import org.apache.spark.sql.execution.streaming.ManifestFileCommitProtocol
-import org.apache.spark.util.Utils
+import org.apache.spark.sql.catalyst.analysis.Resolver
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 // This file defines the configuration options for Spark SQL.
@@ -251,7 +247,7 @@ object SQLConf {
       "of org.apache.parquet.hadoop.ParquetOutputCommitter.")
     .internal()
     .stringConf
-    .createWithDefault(classOf[ParquetOutputCommitter].getName)
+    .createWithDefault("org.apache.parquet.hadoop.ParquetOutputCommitter")
 
   val PARQUET_VECTORIZED_READER_ENABLED =
     buildConf("spark.sql.parquet.enableVectorizedReader")
@@ -417,7 +413,8 @@ object SQLConf {
     buildConf("spark.sql.sources.commitProtocolClass")
       .internal()
       .stringConf
-      .createWithDefault(classOf[SQLHadoopMapReduceCommitProtocol].getName)
+      .createWithDefault(
+        "org.apache.spark.sql.execution.datasources.SQLHadoopMapReduceCommitProtocol")
 
   val PARALLEL_PARTITION_DISCOVERY_THRESHOLD =
     buildConf("spark.sql.sources.parallelPartitionDiscovery.threshold")
@@ -578,7 +575,7 @@ object SQLConf {
     buildConf("spark.sql.streaming.commitProtocolClass")
       .internal()
       .stringConf
-      .createWithDefault(classOf[ManifestFileCommitProtocol].getName)
+      .createWithDefault("org.apache.spark.sql.execution.streaming.ManifestFileCommitProtocol")
 
   val OBJECT_AGG_SORT_BASED_FALLBACK_THRESHOLD =
     buildConf("spark.sql.objectHashAggregate.sortBased.fallbackThreshold")
@@ -723,7 +720,7 @@ object SQLConf {
  *
  * SQLConf is thread-safe (internally synchronized, so safe to be used in multiple threads).
  */
-private[sql] class SQLConf extends Serializable with CatalystConf with Logging {
+class SQLConf extends Serializable with Logging {
   import SQLConf._
 
   /** Only low degree of contention is expected for conf, thus NOT using ConcurrentHashMap. */
@@ -833,6 +830,18 @@ private[sql] class SQLConf extends Serializable with CatalystConf with Logging {
 
   def caseSensitiveAnalysis: Boolean = getConf(SQLConf.CASE_SENSITIVE)
 
+  /**
+   * Returns the [[Resolver]] for the current configuration, which can be used to determine if two
+   * identifiers are equal.
+   */
+  def resolver: Resolver = {
+    if (caseSensitiveAnalysis) {
+      org.apache.spark.sql.catalyst.analysis.caseSensitiveResolution
+    } else {
+      org.apache.spark.sql.catalyst.analysis.caseInsensitiveResolution
+    }
+  }
+
   def subexpressionEliminationEnabled: Boolean =
     getConf(SUBEXPRESSION_ELIMINATION_ENABLED)
 
@@ -890,7 +899,7 @@ private[sql] class SQLConf extends Serializable with CatalystConf with Logging {
 
   def dataFramePivotMaxValues: Int = getConf(DATAFRAME_PIVOT_MAX_VALUES)
 
-  override def runSQLonFile: Boolean = getConf(RUN_SQL_ON_FILES)
+  def runSQLonFile: Boolean = getConf(RUN_SQL_ON_FILES)
 
   def enableTwoLevelAggMap: Boolean = getConf(ENABLE_TWOLEVEL_AGG_MAP)
 
@@ -907,21 +916,21 @@ private[sql] class SQLConf extends Serializable with CatalystConf with Logging {
   def hiveThriftServerSingleSession: Boolean =
     getConf(StaticSQLConf.HIVE_THRIFT_SERVER_SINGLESESSION)
 
-  override def orderByOrdinal: Boolean = getConf(ORDER_BY_ORDINAL)
+  def orderByOrdinal: Boolean = getConf(ORDER_BY_ORDINAL)
 
-  override def groupByOrdinal: Boolean = getConf(GROUP_BY_ORDINAL)
+  def groupByOrdinal: Boolean = getConf(GROUP_BY_ORDINAL)
 
-  override def crossJoinEnabled: Boolean = getConf(SQLConf.CROSS_JOINS_ENABLED)
+  def crossJoinEnabled: Boolean = getConf(SQLConf.CROSS_JOINS_ENABLED)
 
-  override def sessionLocalTimeZone: String = getConf(SQLConf.SESSION_LOCAL_TIMEZONE)
+  def sessionLocalTimeZone: String = getConf(SQLConf.SESSION_LOCAL_TIMEZONE)
 
   def ndvMaxError: Double = getConf(NDV_MAX_ERROR)
 
-  override def cboEnabled: Boolean = getConf(SQLConf.CBO_ENABLED)
+  def cboEnabled: Boolean = getConf(SQLConf.CBO_ENABLED)
 
-  override def joinReorderEnabled: Boolean = getConf(SQLConf.JOIN_REORDER_ENABLED)
+  def joinReorderEnabled: Boolean = getConf(SQLConf.JOIN_REORDER_ENABLED)
 
-  override def joinReorderDPThreshold: Int = getConf(SQLConf.JOIN_REORDER_DP_THRESHOLD)
+  def joinReorderDPThreshold: Int = getConf(SQLConf.JOIN_REORDER_DP_THRESHOLD)
 
   /** ********************** SQLConf functionality methods ************ */
 
@@ -1050,66 +1059,3 @@ private[sql] class SQLConf extends Serializable with CatalystConf with Logging {
     result
   }
 }
-
-/**
- * Static SQL configuration is a cross-session, immutable Spark configuration. External users can
- * see the static sql configs via `SparkSession.conf`, but can NOT set/unset them.
- */
-object StaticSQLConf {
-
-  import SQLConf.buildStaticConf
-
-  val WAREHOUSE_PATH = buildStaticConf("spark.sql.warehouse.dir")
-    .doc("The default location for managed databases and tables.")
-    .stringConf
-    .createWithDefault(Utils.resolveURI("spark-warehouse").toString)
-
-  val CATALOG_IMPLEMENTATION = buildStaticConf("spark.sql.catalogImplementation")
-    .internal()
-    .stringConf
-    .checkValues(Set("hive", "in-memory"))
-    .createWithDefault("in-memory")
-
-  val GLOBAL_TEMP_DATABASE = buildStaticConf("spark.sql.globalTempDatabase")
-    .internal()
-    .stringConf
-    .createWithDefault("global_temp")
-
-  // This is used to control when we will split a schema's JSON string to multiple pieces
-  // in order to fit the JSON string in metastore's table property (by default, the value has
-  // a length restriction of 4000 characters, so do not use a value larger than 4000 as the default
-  // value of this property). We will split the JSON string of a schema to its length exceeds the
-  // threshold. Note that, this conf is only read in HiveExternalCatalog which is cross-session,
-  // that's why this conf has to be a static SQL conf.
-  val SCHEMA_STRING_LENGTH_THRESHOLD =
-    buildStaticConf("spark.sql.sources.schemaStringLengthThreshold")
-      .doc("The maximum length allowed in a single cell when " +
-        "storing additional schema information in Hive's metastore.")
-      .internal()
-      .intConf
-      .createWithDefault(4000)
-
-  val FILESOURCE_TABLE_RELATION_CACHE_SIZE =
-    buildStaticConf("spark.sql.filesourceTableRelationCacheSize")
-      .internal()
-      .doc("The maximum size of the cache that maps qualified table names to table relation plans.")
-      .intConf
-      .checkValue(cacheSize => cacheSize >= 0, "The maximum size of the cache must not be negative")
-      .createWithDefault(1000)
-
-  // When enabling the debug, Spark SQL internal table properties are not filtered out; however,
-  // some related DDL commands (e.g., ANALYZE TABLE and CREATE TABLE LIKE) might not work properly.
-  val DEBUG_MODE = buildStaticConf("spark.sql.debug")
-    .internal()
-    .doc("Only used for internal debugging. Not all functions are supported when it is enabled.")
-    .booleanConf
-    .createWithDefault(false)
-
-  val HIVE_THRIFT_SERVER_SINGLESESSION =
-    buildStaticConf("spark.sql.hive.thriftServer.singleSession")
-      .doc("When set to true, Hive Thrift server is running in a single session mode. " +
-        "All the JDBC/ODBC connections share the temporary views, function registries, " +
-        "SQL configuration and the current database.")
-      .booleanConf
-      .createWithDefault(false)
-}
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/internal/StaticSQLConf.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/internal/StaticSQLConf.scala
new file mode 100644
index 0000000000..af1a9cee29
--- /dev/null
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/internal/StaticSQLConf.scala
@@ -0,0 +1,84 @@
+/*
+ * 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.util.Utils
+
+
+/**
+ * Static SQL configuration is a cross-session, immutable Spark configuration. External users can
+ * see the static sql configs via `SparkSession.conf`, but can NOT set/unset them.
+ */
+object StaticSQLConf {
+
+  import SQLConf.buildStaticConf
+
+  val WAREHOUSE_PATH = buildStaticConf("spark.sql.warehouse.dir")
+    .doc("The default location for managed databases and tables.")
+    .stringConf
+    .createWithDefault(Utils.resolveURI("spark-warehouse").toString)
+
+  val CATALOG_IMPLEMENTATION = buildStaticConf("spark.sql.catalogImplementation")
+    .internal()
+    .stringConf
+    .checkValues(Set("hive", "in-memory"))
+    .createWithDefault("in-memory")
+
+  val GLOBAL_TEMP_DATABASE = buildStaticConf("spark.sql.globalTempDatabase")
+    .internal()
+    .stringConf
+    .createWithDefault("global_temp")
+
+  // This is used to control when we will split a schema's JSON string to multiple pieces
+  // in order to fit the JSON string in metastore's table property (by default, the value has
+  // a length restriction of 4000 characters, so do not use a value larger than 4000 as the default
+  // value of this property). We will split the JSON string of a schema to its length exceeds the
+  // threshold. Note that, this conf is only read in HiveExternalCatalog which is cross-session,
+  // that's why this conf has to be a static SQL conf.
+  val SCHEMA_STRING_LENGTH_THRESHOLD =
+    buildStaticConf("spark.sql.sources.schemaStringLengthThreshold")
+      .doc("The maximum length allowed in a single cell when " +
+        "storing additional schema information in Hive's metastore.")
+      .internal()
+      .intConf
+      .createWithDefault(4000)
+
+  val FILESOURCE_TABLE_RELATION_CACHE_SIZE =
+    buildStaticConf("spark.sql.filesourceTableRelationCacheSize")
+      .internal()
+      .doc("The maximum size of the cache that maps qualified table names to table relation plans.")
+      .intConf
+      .checkValue(cacheSize => cacheSize >= 0, "The maximum size of the cache must not be negative")
+      .createWithDefault(1000)
+
+  // When enabling the debug, Spark SQL internal table properties are not filtered out; however,
+  // some related DDL commands (e.g., ANALYZE TABLE and CREATE TABLE LIKE) might not work properly.
+  val DEBUG_MODE = buildStaticConf("spark.sql.debug")
+    .internal()
+    .doc("Only used for internal debugging. Not all functions are supported when it is enabled.")
+    .booleanConf
+    .createWithDefault(false)
+
+  val HIVE_THRIFT_SERVER_SINGLESESSION =
+    buildStaticConf("spark.sql.hive.thriftServer.singleSession")
+      .doc("When set to true, Hive Thrift server is running in a single session mode. " +
+        "All the JDBC/ODBC connections share the temporary views, function registries, " +
+        "SQL configuration and the current database.")
+      .booleanConf
+      .createWithDefault(false)
+}