diff --git a/planner/core/plan_cache.go b/planner/core/plan_cache.go
index 13bdde829e48e..6702a4c582a97 100644
--- a/planner/core/plan_cache.go
+++ b/planner/core/plan_cache.go
@@ -44,7 +44,7 @@ import (
 )
 
 var (
-	// PlanCacheKeyTestIssue43667 is for test.
+	// PlanCacheKeyTestIssue43667 is only for test.
 	PlanCacheKeyTestIssue43667 struct{}
 )
 
diff --git a/sessionctx/variable/tidb_vars.go b/sessionctx/variable/tidb_vars.go
index 381c86c39daa6..31a8a80d1f607 100644
--- a/sessionctx/variable/tidb_vars.go
+++ b/sessionctx/variable/tidb_vars.go
@@ -1310,7 +1310,7 @@ const (
 	DefTiDBEnableFastReorg                         = true
 	DefTiDBDDLDiskQuota                            = 100 * 1024 * 1024 * 1024 // 100GB
 	DefExecutorConcurrency                         = 5
-	DefTiDBEnableNonPreparedPlanCache              = true
+	DefTiDBEnableNonPreparedPlanCache              = false
 	DefTiDBEnableNonPreparedPlanCacheForDML        = false
 	DefTiDBNonPreparedPlanCacheSize                = 100
 	DefTiDBPlanCacheMaxPlanSize                    = 2 * size.MB