diff --git a/dbms/src/Interpreters/Aggregator.h b/dbms/src/Interpreters/Aggregator.h
index 330d1f5c5f3..60de0a195c3 100644
--- a/dbms/src/Interpreters/Aggregator.h
+++ b/dbms/src/Interpreters/Aggregator.h
@@ -1316,7 +1316,7 @@ class Aggregator
 
         bool only_lookup = false;
         size_t hit_row_cnt = 0;
-        std::vector<size_t> not_found_rows;
+        std::vector<UInt64> not_found_rows;
 
         void prepareForAgg();
         bool allBlockDataHandled() const