diff --git a/config/config.go b/config/config.go
index 123287b505dda..322294b987827 100644
--- a/config/config.go
+++ b/config/config.go
@@ -534,7 +534,7 @@ type Experimental struct {
 	// Whether enable creating expression index.
 	AllowsExpressionIndex bool `toml:"allow-expression-index" json:"allow-expression-index"`
 	// Whether enable global kill.
-	EnableGlobalKill bool `toml:"enable-global-kill" json:"enable-global-kill"`
+	EnableGlobalKill bool `toml:"enable-global-kill" json:"-"`
 }
 
 var defTiKVCfg = tikvcfg.DefaultConfig()
diff --git a/config/config.toml.example b/config/config.toml.example
index 227836889f597..940936845abf3 100644
--- a/config/config.toml.example
+++ b/config/config.toml.example
@@ -463,8 +463,6 @@ history-size = 24
 [experimental]
 # enable creating expression index.
 allow-expression-index = false
-# enable global kill.
-enable-global-kill = false
 
 # server level isolation read by engines and labels
 [isolation-read]
diff --git a/executor/show_test.go b/executor/show_test.go
index 61ec2e5bd1ec1..032c4d08839c8 100644
--- a/executor/show_test.go
+++ b/executor/show_test.go
@@ -1131,6 +1131,17 @@ func (s *testSuite5) TestInvisibleCoprCacheConfig(c *C) {
 	c.Assert(strings.Contains(configValue, coprCacheVal), Equals, true)
 }
 
+func (s *testSuite5) TestInvisibleGlobalKillConfig(c *C) {
+	se1, err := session.CreateSession(s.store)
+	c.Assert(err, IsNil)
+	tk := testkit.NewTestKitWithSession(c, s.store, se1)
+	rows := tk.MustQuery("show variables like '%config%'").Rows()
+	c.Assert(len(rows), Equals, 1)
+	configValue := rows[0][1].(string)
+	globalKillVal := "global-kill"
+	c.Assert(strings.Contains(configValue, globalKillVal), Equals, false)
+}
+
 func (s *testSerialSuite1) TestShowCreateTableWithIntegerDisplayLengthWarnings(c *C) {
 	parsertypes.TiDBStrictIntegerDisplayWidth = true
 	defer func() {
diff --git a/sessionctx/variable/tidb_vars.go b/sessionctx/variable/tidb_vars.go
index 8acc5841bd1a6..dcedbd56affc6 100644
--- a/sessionctx/variable/tidb_vars.go
+++ b/sessionctx/variable/tidb_vars.go
@@ -714,6 +714,7 @@ var FeatureSwitchVariables = []string{
 	TiDBPartitionPruneMode,
 	TiDBIntPrimaryKeyDefaultAsClustered,
 	TiDBEnableExtendedStats,
+	TiDBEnableIndexMergeJoin,
 }
 
 // FilterImplicitFeatureSwitch is used to filter result of show variables, these switches should be turn blind to users.