diff --git a/pkg/tsdb/elasticsearch/time_series_query.go b/pkg/tsdb/elasticsearch/time_series_query.go
index fddcf3cb8b3..45a63ad5c3f 100644
--- a/pkg/tsdb/elasticsearch/time_series_query.go
+++ b/pkg/tsdb/elasticsearch/time_series_query.go
@@ -171,6 +171,10 @@ func addTermsAgg(aggBuilder es.AggBuilder, bucketAgg *BucketAgg, metrics []*Metr
 		} else {
 			a.Size = 500
 		}
+		if a.Size == 0 {
+		    a.Size = 500
+		}
+		
 		if minDocCount, err := bucketAgg.Settings.Get("min_doc_count").Int(); err == nil {
 			a.MinDocCount = &minDocCount
 		}