diff --git a/src/modules/index/cache/metric_map.go b/src/modules/index/cache/metric_map.go
index e644b9f0..114f0e10 100644
--- a/src/modules/index/cache/metric_map.go
+++ b/src/modules/index/cache/metric_map.go
@@ -27,7 +27,6 @@ func NewMetricIndex(item dataobj.IndexModel, counter string, now int64) *MetricI
 		Ts:         now,
 	}
 
-	metricIndex.TagkvMap = NewTagkvIndex()
 	for k, v := range item.Tags {
 		metricIndex.TagkvMap.Set(k, v, now)
 	}