diff --git a/internal/util/metricsinfo/cache.go b/internal/util/metricsinfo/cache.go
index b9a3bf5187..6737765e69 100644
--- a/internal/util/metricsinfo/cache.go
+++ b/internal/util/metricsinfo/cache.go
@@ -93,7 +93,7 @@ func (manager *MetricsCacheManager) GetSystemInfoMetrics() (*milvuspb.GetMetrics
 		manager.systemInfoMetrics == nil ||
 		time.Since(manager.systemInfoMetricsLastUpdatedTime) >= retention {
 
-		return nil, ErrInvalidSystemInfosMetricCache
+		return nil, errInvalidSystemInfosMetricCache
 	}
 
 	return manager.systemInfoMetrics, nil
diff --git a/internal/util/metricsinfo/err.go b/internal/util/metricsinfo/err.go
index c6e2927459..3be81b21a4 100644
--- a/internal/util/metricsinfo/err.go
+++ b/internal/util/metricsinfo/err.go
@@ -14,9 +14,9 @@ package metricsinfo
 import "errors"
 
 const (
+	// MsgUnimplementedMetric represents that user requests a unimplemented metric type
 	MsgUnimplementedMetric           = "sorry, but this metric type is not implemented"
-	MsgInvalidSystemInfosMetricCache = "system infos metric is invalid"
+	msgInvalidSystemInfosMetricCache = "system infos metric is invalid"
 )
 
-var ErrUnimplementedMetric = errors.New(MsgUnimplementedMetric)
-var ErrInvalidSystemInfosMetricCache = errors.New(MsgInvalidSystemInfosMetricCache)
+var errInvalidSystemInfosMetricCache = errors.New(msgInvalidSystemInfosMetricCache)