diff --git a/be/src/agent/be_exec_version_manager.h b/be/src/agent/be_exec_version_manager.h
index 657ebab02d..0ecc868651 100644
--- a/be/src/agent/be_exec_version_manager.h
+++ b/be/src/agent/be_exec_version_manager.h
@@ -56,7 +56,8 @@ private:
  *    a. function month/day/hour/minute/second's return type is changed to smaller type.
  *    b. in order to solve agg of sum/count is not compatibility during the upgrade process
  *    c. change the string hash method in runtime filter
- *
+ *    d. elt funciton return type change to nullable(string)
+ *    e. add repeat_max_num in repeat function
 */
 inline const int BeExecVersionManager::max_be_exec_version = 2;
 inline const int BeExecVersionManager::min_be_exec_version = 0;
diff --git a/be/src/vec/functions/function_string.cpp b/be/src/vec/functions/function_string.cpp
index dbfbff8800..5812c7badb 100644
--- a/be/src/vec/functions/function_string.cpp
+++ b/be/src/vec/functions/function_string.cpp
@@ -965,7 +965,7 @@ void register_function_string(SimpleFunctionFactory& factory) {
     factory.register_function<FunctionStringElt>();
     factory.register_function<FunctionStringConcatWs>();
     factory.register_function<FunctionStringAppendTrailingCharIfAbsent>();
-    factory.register_function<FunctionStringRepeat>();
+    factory.register_function<FunctionStringRepeat<false>>();
     factory.register_function<FunctionStringLPad>();
     factory.register_function<FunctionStringRPad>();
     factory.register_function<FunctionToBase64>();
@@ -996,6 +996,10 @@ void register_function_string(SimpleFunctionFactory& factory) {
     factory.register_alias(FunctionStringMd5AndSM3<MD5Sum>::name, "md5");
     factory.register_alias(FunctionStringUTF8Length::name, "character_length");
     factory.register_alias(FunctionStringMd5AndSM3<SM3Sum>::name, "sm3");
+
+    /// @TEMPORARY: for be_exec_version=2
+    factory.register_alternative_function<FunctionStringEltOld>();
+    factory.register_alternative_function<FunctionStringRepeat<true>>();
 }
 
 } // namespace doris::vectorized
diff --git a/be/src/vec/functions/function_string.h b/be/src/vec/functions/function_string.h
index ff48e01e26..83f98d726a 100644
--- a/be/src/vec/functions/function_string.h
+++ b/be/src/vec/functions/function_string.h
@@ -914,6 +914,48 @@ public:
     }
 };
 
+class FunctionStringEltOld : public IFunction {
+public:
+    static constexpr auto name = "elt";
+    static FunctionPtr create() { return std::make_shared<FunctionStringEltOld>(); }
+    String get_name() const override { return name; }
+    size_t get_number_of_arguments() const override { return 0; }
+    bool is_variadic() const override { return true; }
+
+    DataTypePtr get_return_type_impl(const DataTypes& arguments) const override {
+        return std::make_shared<DataTypeString>();
+    }
+    bool use_default_implementation_for_nulls() const override { return true; }
+    bool use_default_implementation_for_constants() const override { return true; }
+
+    Status execute_impl(FunctionContext* context, Block& block, const ColumnNumbers& arguments,
+                        size_t result, size_t input_rows_count) override {
+        int arguent_size = arguments.size();
+        auto pos_col =
+                block.get_by_position(arguments[0]).column->convert_to_full_column_if_const();
+        if (auto* nullable = check_and_get_column<const ColumnNullable>(*pos_col)) {
+            pos_col = nullable->get_nested_column_ptr();
+        }
+        auto& pos_data = assert_cast<const ColumnInt32*>(pos_col.get())->get_data();
+        auto pos = pos_data[0];
+        int num_children = arguent_size - 1;
+        if (pos < 1 || num_children == 0 || pos > num_children) {
+            auto null_map = ColumnUInt8::create(input_rows_count, 1);
+            auto res = ColumnString::create();
+            auto& res_data = res->get_chars();
+            auto& res_offset = res->get_offsets();
+            res_offset.resize(input_rows_count);
+            for (size_t i = 0; i < input_rows_count; ++i) {
+                res_offset[i] = res_data.size();
+            }
+            block.get_by_position(result).column =
+                    ColumnNullable::create(std::move(res), std::move(null_map));
+            return Status::OK();
+        }
+        block.get_by_position(result).column = block.get_by_position(arguments[pos]).column;
+        return Status::OK();
+    }
+};
 // concat_ws (string,string....) or (string, Array)
 // TODO: avoid use fmtlib
 class FunctionStringConcatWs : public IFunction {
@@ -1123,7 +1165,7 @@ private:
         }
     }
 };
-
+template <bool use_old_function>
 class FunctionStringRepeat : public IFunction {
 public:
     static constexpr auto name = "repeat";
@@ -1155,8 +1197,13 @@ public:
                 return Status::OK();
             } else if (auto* col2_const = check_and_get_column<ColumnConst>(*argument_ptr[1])) {
                 DCHECK(check_and_get_column<ColumnInt32>(col2_const->get_data_column()));
-                int repeat =
-                        std::min<int>(col2_const->get_int(0), context->state()->repeat_max_num());
+                int repeat = 0;
+                if constexpr (use_old_function) {
+                    repeat = col2_const->get_int(0);
+                } else {
+                    repeat = std::min<int>(col2_const->get_int(0),
+                                           context->state()->repeat_max_num());
+                }
                 if (repeat <= 0) {
                     null_map->get_data().resize_fill(input_rows_count, 0);
                     res->insert_many_defaults(input_rows_count);
@@ -1187,8 +1234,12 @@ public:
             buffer.clear();
             const char* raw_str = reinterpret_cast<const char*>(&data[offsets[i - 1]]);
             size_t size = offsets[i] - offsets[i - 1];
-            int repeat = std::min<int>(repeats[i], repeat_max_num);
-
+            int repeat = 0;
+            if constexpr (use_old_function) {
+                repeat = repeats[i];
+            } else {
+                repeat = std::min<int>(repeats[i], repeat_max_num);
+            }
             if (repeat <= 0) {
                 StringOP::push_empty_string(i, res_data, res_offsets);
             } else if (repeat * size > DEFAULT_MAX_STRING_SIZE) {