diff --git a/lib/storage/index_db.go b/lib/storage/index_db.go
index 8c92f01a4c..807d470ff5 100644
--- a/lib/storage/index_db.go
+++ b/lib/storage/index_db.go
@@ -2287,7 +2287,7 @@ func mergeTagToMetricIDsRows(data []byte, items [][]byte) ([]byte, [][]byte) {
 		dstData, dstItems = tmm.flushPendingMetricIDs(dstData, dstItems, mpPrev)
 	}
 	putTagToMetricIDsRowsMerger(tmm)
-	return data, dstItems
+	return dstData, dstItems
 }
 
 // maxMetricIDsPerRow limits the number of metricIDs in tag->metricIDs row.