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
index 64f88e48cb19e..6e798a53adf27 100644
--- 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
@@ -29,7 +29,7 @@ trait CatalystConf {
   def groupByOrdinal: Boolean
 
   def optimizerMaxIterations: Int
-  def optimizerMinSetSize: Int
+  def optimizerInSetConversionThreshold: Int
   def maxCaseBranchesForCodegen: Int
 
   /**
@@ -48,7 +48,7 @@ case class SimpleCatalystConf(
     orderByOrdinal: Boolean = true,
     groupByOrdinal: Boolean = true,
     optimizerMaxIterations: Int = 100,
-    optimizerMinSetSize: Int = 10,
+    optimizerInSetConversionThreshold: Int = 10,
     maxCaseBranchesForCodegen: Int = 20)
   extends CatalystConf {
 }
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala
index 6f4dfac98ca4b..ffd7c2eb71bf5 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala
@@ -686,7 +686,7 @@ case class OptimizeIn(conf: CatalystConf) extends Rule[LogicalPlan] {
   def apply(plan: LogicalPlan): LogicalPlan = plan transform {
     case q: LogicalPlan => q transformExpressionsDown {
       case In(v, list) if !list.exists(!_.isInstanceOf[Literal]) &&
-          list.size > conf.optimizerMinSetSize =>
+          list.size > conf.optimizerInSetConversionThreshold =>
         val hSet = list.map(e => e.eval(EmptyRow))
         InSet(v, HashSet() ++ hSet)
     }
diff --git a/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/OptimizeInSuite.scala b/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/OptimizeInSuite.scala
index e1f4f3d88e59c..f1a4ea8280ab7 100644
--- a/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/OptimizeInSuite.scala
+++ b/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/OptimizeInSuite.scala
@@ -17,8 +17,6 @@
 
 package org.apache.spark.sql.catalyst.optimizer
 
-import scala.collection.immutable.HashSet
-
 import org.apache.spark.sql.catalyst.SimpleCatalystConf
 import org.apache.spark.sql.catalyst.analysis.{EliminateSubqueryAliases, UnresolvedAttribute}
 import org.apache.spark.sql.catalyst.dsl.expressions._
@@ -39,7 +37,7 @@ class OptimizeInSuite extends PlanTest {
         NullPropagation,
         ConstantFolding,
         BooleanSimplification,
-        OptimizeIn(SimpleCatalystConf(true))) :: Nil
+        OptimizeIn(SimpleCatalystConf(caseSensitiveAnalysis = true))) :: Nil
   }
 
   val testRelation = LocalRelation('a.int, 'b.int, 'c.int)
@@ -131,16 +129,18 @@ class OptimizeInSuite extends PlanTest {
     comparePlans(optimized, correctAnswer)
   }
 
-  test("OptimizedIn test: Use configuration.") {
+  test("OptimizedIn test: Setting the threshold for turning Set into InSet.") {
     val plan =
       testRelation
         .where(In(UnresolvedAttribute("a"), Seq(Literal(1), Literal(2), Literal(3))))
         .analyze
 
-    val notOptimizedPlan = OptimizeIn(SimpleCatalystConf(true))(plan)
+    val notOptimizedPlan = OptimizeIn(SimpleCatalystConf(caseSensitiveAnalysis = true))(plan)
     comparePlans(notOptimizedPlan, plan)
 
-    val optimizedPlan = OptimizeIn(SimpleCatalystConf(true, optimizerMinSetSize = 2))(plan)
+    // Reduce the threshold to turning into InSet.
+    val optimizedPlan = OptimizeIn(SimpleCatalystConf(caseSensitiveAnalysis = true,
+        optimizerInSetConversionThreshold = 2))(plan)
     optimizedPlan match {
       case Filter(cond, _)
         if cond.isInstanceOf[InSet] && cond.asInstanceOf[InSet].getHSet().size == 3 =>
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/internal/SQLConf.scala b/sql/core/src/main/scala/org/apache/spark/sql/internal/SQLConf.scala
index a3d4ed52edffe..33cf21e7aed9a 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/internal/SQLConf.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/internal/SQLConf.scala
@@ -58,11 +58,12 @@ object SQLConf {
     .intConf
     .createWithDefault(100)
 
-  val OPTIMIZER_MIN_SET_SIZE = SQLConfigBuilder("spark.sql.optimizer.minSetSize")
-    .internal()
-    .doc("The minimum threshold of set size to be optimized.")
-    .intConf
-    .createWithDefault(10)
+  val OPTIMIZER_INSET_CONVERSION_THRESHOLD =
+    SQLConfigBuilder("spark.sql.optimizer.inSetConversionThreshold")
+      .internal()
+      .doc("The threshold of set size for InSet conversion.")
+      .intConf
+      .createWithDefault(10)
 
   val ALLOW_MULTIPLE_CONTEXTS = SQLConfigBuilder("spark.sql.allowMultipleContexts")
     .doc("When set to true, creating multiple SQLContexts/HiveContexts is allowed. " +
@@ -535,7 +536,7 @@ private[sql] class SQLConf extends Serializable with CatalystConf with Logging {
 
   def optimizerMaxIterations: Int = getConf(OPTIMIZER_MAX_ITERATIONS)
 
-  def optimizerMinSetSize: Int = getConf(OPTIMIZER_MIN_SET_SIZE)
+  def optimizerInSetConversionThreshold: Int = getConf(OPTIMIZER_INSET_CONVERSION_THRESHOLD)
 
   def checkpointLocation: String = getConf(CHECKPOINT_LOCATION)