diff --git a/internal/monitor/metrics.go b/internal/monitor/metrics.go
index 355fe42..4ba77a2 100644
--- a/internal/monitor/metrics.go
+++ b/internal/monitor/metrics.go
@@ -138,9 +138,12 @@ func positionMap(pos mysql.Position) map[string]interface{} {
 }
 
 func positionGap(master mysql.Position, checkpoint mysql.Position) interface{} {
-	if master.Name == "" || checkpoint.Name == "" || master.Name != checkpoint.Name || master.Pos < checkpoint.Pos {
+	if master.Name == "" || checkpoint.Name == "" || master.Name != checkpoint.Name {
 		return nil
 	}
+	if master.Pos < checkpoint.Pos {
+		return uint32(0)
+	}
 	return master.Pos - checkpoint.Pos
 }