diff --git a/ydb/core/tablet_flat/flat_mem_iter.h b/ydb/core/tablet_flat/flat_mem_iter.h
index 23b2954122a7..708cea404e0e 100644
--- a/ydb/core/tablet_flat/flat_mem_iter.h
+++ b/ydb/core/tablet_flat/flat_mem_iter.h
@@ -133,13 +133,13 @@ namespace NTable {
             const auto *key = RowIt.GetKey();
 
             if (len >= KeyCellDefaults->BasicTypes().size()) {
-                return { KeyCellDefaults->BasicTypes().begin(), key, len };
+                return { KeyCellDefaults->BasicTypes().data(), key, len };
             } else if (!Key) {
                 Key.insert(Key.end(), key, key + len);
                 Key.insert(Key.end(), (**KeyCellDefaults).begin() + len, (**KeyCellDefaults).end());
             }
 
-            return { KeyCellDefaults->BasicTypes().begin(), Key.begin(), ui32(Key.size()) };
+            return { KeyCellDefaults->BasicTypes().data(), Key.data(), ui32(Key.size()) };
         }
 
         bool IsDelta() const