diff --git a/pkg/monitor/models/alertrecord.go b/pkg/monitor/models/alertrecord.go
index 0485d79f9a..205b7406d2 100644
--- a/pkg/monitor/models/alertrecord.go
+++ b/pkg/monitor/models/alertrecord.go
@@ -55,8 +55,8 @@ type SAlertRecord struct {
 	Level     string               `charset:"ascii" width:"36" nullable:"false" default:"normal" list:"user" update:"user"`
 	State     string               `width:"36" charset:"ascii" nullable:"false" default:"unknown" list:"user" update:"user"`
 	SendState string               `width:"36" charset:"ascii" default:"ok" list:"user" update:"user"`
-	EvalData  jsonutils.JSONObject `list:"user" update:"user" length:""`
-	AlertRule jsonutils.JSONObject `list:"user" update:"user" length:""`
+	EvalData  jsonutils.JSONObject `list:"user" update:"user" length:"medium"`
+	AlertRule jsonutils.JSONObject `list:"user" update:"user" length:"medium"`
 	ResType   string               `width:"36" list:"user" update:"user"`
 }