diff --git a/be/src/vec/columns/column_dictionary.h b/be/src/vec/columns/column_dictionary.h
index 354fb78e2e..122f15d9f0 100644
--- a/be/src/vec/columns/column_dictionary.h
+++ b/be/src/vec/columns/column_dictionary.h
@@ -293,7 +293,7 @@ public:
             convert_dict_codes_if_necessary();
         }
         auto res = vectorized::PredicateColumnType<TYPE_STRING>::create();
-        res->reserve(_codes.size());
+        res->reserve(_codes.capacity());
         for (size_t i = 0; i < _codes.size(); ++i) {
             auto& code = reinterpret_cast<T&>(_codes[i]);
             auto value = _dict.get_value(code);