diff --git a/include/common/tdatablock.h b/include/common/tdatablock.h
index 3a98102661a347f6605c6d94dd53e8e32a5a5b9a..4b36b67e43b67a25c4531f7a6e7abfc810a27765 100644
--- a/include/common/tdatablock.h
+++ b/include/common/tdatablock.h
@@ -54,6 +54,11 @@ SEpSet getEpSet_s(SCorEpSet* pEpSet);
     BMCharPos(bm_, r_) |= (1u << (7u - BitPos(r_))); \
   } while (0)
 
+#define colDataSetNotNull_f(bm_, r_)                  \
+  do {                                                \
+    BMCharPos(bm_, r_) &= ~(1u << (7u - BitPos(r_)));  \
+  } while (0)
+
 #define colDataIsNull_var(pColumnInfoData, row) (pColumnInfoData->varmeta.offset[row] == -1)
 #define colDataSetNull_var(pColumnInfoData, row)  (pColumnInfoData->varmeta.offset[row] = -1)
 
diff --git a/include/libs/function/tudf.h b/include/libs/function/tudf.h
index 5207a73487d81c9bdb5a0e4f95c927345ee0dd26..22314e4bd667a9f4619386f01ba3633cde73581c 100644
--- a/include/libs/function/tudf.h
+++ b/include/libs/function/tudf.h
@@ -22,6 +22,7 @@
 #include "tmsg.h"
 #include "tcommon.h"
 #include "function.h"
+#include "tdatablock.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -61,7 +62,7 @@ typedef struct SUdfColumnMeta {
 
 typedef struct SUdfColumnData {
   int32_t numOfRows;
-  bool varLengthColumn;
+  int32_t rowsAlloc;
   union {
     struct {
       int32_t nullBitmapLen;
@@ -72,9 +73,10 @@ typedef struct SUdfColumnData {
 
     struct {
       int32_t varOffsetsLen;
-      char   *varOffsets;
+      int32_t   *varOffsets;
       int32_t payloadLen;
       char   *payload;
+      int32_t payloadAllocLen;
     } varLenCol;
   };
 } SUdfColumnData;
@@ -131,9 +133,114 @@ typedef int32_t (*TUdfSetupFunc)();
 typedef int32_t (*TUdfTeardownFunc)();
 
 //TODO: add API to check function arguments type, number etc.
-//TODO: another way to manage memory is provide api for UDF to add data to SUdfColumnData and UDF framework will allocate memory.
-// then UDF framework will free the memory
-// int32_t udfColDataAppend(SUdfColumn* pColumn, uint32_t currentRow, const char* pData, bool isNull)
+
+#define UDF_MEMORY_EXP_GROWTH 1.5
+
+static FORCE_INLINE int32_t udfColEnsureCapacity(SUdfColumn* pColumn, int32_t newCapacity) {
+  SUdfColumnMeta *meta = &pColumn->colMeta;
+  SUdfColumnData *data = &pColumn->colData;
+
+  if (newCapacity== 0 || newCapacity <= data->rowsAlloc) {
+    return TSDB_CODE_SUCCESS;
+  }
+
+  int allocCapacity = MAX(data->rowsAlloc, 8);
+  while (allocCapacity < newCapacity) {
+    allocCapacity *= UDF_MEMORY_EXP_GROWTH;
+  }
+
+  if (IS_VAR_DATA_TYPE(meta->type)) {
+    char* tmp = taosMemoryRealloc(data->varLenCol.varOffsets, sizeof(int32_t) * allocCapacity);
+    if (tmp == NULL) {
+      return TSDB_CODE_OUT_OF_MEMORY;
+    }
+    data->varLenCol.varOffsets = (int32_t*)tmp;
+    data->varLenCol.varOffsetsLen = sizeof(int32_t) * allocCapacity;
+    // for payload, add data in udfColDataAppend
+  } else {
+    char* tmp = taosMemoryRealloc(data->fixLenCol.nullBitmap, BitmapLen(allocCapacity));
+    if (tmp == NULL) {
+      return TSDB_CODE_OUT_OF_MEMORY;
+    }
+    data->fixLenCol.nullBitmap = tmp;
+    data->fixLenCol.nullBitmapLen = BitmapLen(allocCapacity);
+    if (meta->type == TSDB_DATA_TYPE_NULL) {
+      return TSDB_CODE_SUCCESS;
+    }
+
+    tmp = taosMemoryRealloc(data->fixLenCol.data, allocCapacity* meta->bytes);
+    if (tmp == NULL) {
+      return TSDB_CODE_OUT_OF_MEMORY;
+    }
+
+    data->fixLenCol.data = tmp;
+    data->fixLenCol.dataLen = allocCapacity* meta->bytes;
+  }
+
+  data->rowsAlloc = allocCapacity;
+
+  return TSDB_CODE_SUCCESS;
+}
+
+static FORCE_INLINE int32_t udfColSetRow(SUdfColumn* pColumn, uint32_t currentRow, const char* pData, bool isNull) {
+  SUdfColumnMeta *meta = &pColumn->colMeta;
+  SUdfColumnData *data = &pColumn->colData;
+  udfColEnsureCapacity(pColumn, currentRow+1);
+  bool isVarCol = IS_VAR_DATA_TYPE(meta->type);
+  if (isNull) {
+    if (isVarCol) {
+      data->varLenCol.varOffsets[currentRow] = -1;
+    } else {
+      colDataSetNull_f(data->fixLenCol.nullBitmap, currentRow);
+    }
+  } else {
+    if (!isVarCol) {
+      colDataSetNotNull_f(data->fixLenCol.nullBitmap, currentRow);
+      memcpy(data->fixLenCol.data + meta->bytes * currentRow, pData, meta->bytes);
+    } else {
+      int32_t dataLen = varDataTLen(pData);
+      if (meta->type == TSDB_DATA_TYPE_JSON) {
+        if (*pData == TSDB_DATA_TYPE_NULL) {
+          dataLen = 0;
+        } else if (*pData == TSDB_DATA_TYPE_NCHAR) {
+          dataLen = varDataTLen(pData + CHAR_BYTES);
+        } else if (*pData == TSDB_DATA_TYPE_BIGINT || *pData == TSDB_DATA_TYPE_DOUBLE) {
+          dataLen = LONG_BYTES;
+        } else if (*pData == TSDB_DATA_TYPE_BOOL) {
+          dataLen = CHAR_BYTES;
+        }
+        dataLen += CHAR_BYTES;
+      }
+
+      if (data->varLenCol.payloadAllocLen < data->varLenCol.payloadLen + dataLen) {
+        uint32_t newSize = data->varLenCol.payloadAllocLen;
+        if (newSize <= 1) {
+          newSize = 8;
+        }
+
+        while (newSize < data->varLenCol.payloadLen + dataLen) {
+          newSize = newSize * UDF_MEMORY_EXP_GROWTH;
+        }
+
+        char *buf = taosMemoryRealloc(data->varLenCol.payload, newSize);
+        if (buf == NULL) {
+          return TSDB_CODE_OUT_OF_MEMORY;
+        }
+
+        data->varLenCol.payload = buf;
+        data->varLenCol.payloadAllocLen = newSize;
+      }
+
+      uint32_t len = data->varLenCol.payloadLen;
+      data->varLenCol.varOffsets[currentRow] = len;
+
+      memcpy(data->varLenCol.payload + len, pData, dataLen);
+      data->varLenCol.payloadLen += dataLen;
+    }
+  }
+  data->numOfRows = MAX(currentRow + 1, data->numOfRows);
+  return 0;
+}
 
 typedef int32_t (*TUdfFreeUdfColumnFunc)(SUdfColumn* column);
 typedef int32_t (*TUdfScalarProcFunc)(SUdfDataBlock* block, SUdfColumn *resultCol);
diff --git a/source/libs/function/CMakeLists.txt b/source/libs/function/CMakeLists.txt
index 15813b3cb05cc796594dd7be27ad10a0557359b7..c31cabda1960780331650c1db90912db3d314632 100644
--- a/source/libs/function/CMakeLists.txt
+++ b/source/libs/function/CMakeLists.txt
@@ -48,8 +48,7 @@ target_include_directories(
         PRIVATE "${CMAKE_CURRENT_SOURCE_DIR}/inc"
 )
 target_link_libraries(
-    udf1 PUBLIC os
-)
+    udf1 PUBLIC os)
 
 add_library(udf2 MODULE test/udf2.c)
 target_include_directories(
diff --git a/source/libs/function/inc/tudfInt.h b/source/libs/function/inc/tudfInt.h
index 8aedd59c335f2876a5fc4c6a9f958f4ea81dc464..6f82542aee6966d8b4fd7c613263a0639be190a3 100644
--- a/source/libs/function/inc/tudfInt.h
+++ b/source/libs/function/inc/tudfInt.h
@@ -19,9 +19,6 @@
 extern "C" {
 #endif
 
-//TODO replaces them with fnDebug
-//#define debugPrint(...) taosPrintLog("Function", DEBUG_INFO,  135, __VA_ARGS__)
-#define debugPrint(...) {fprintf(stderr, __VA_ARGS__);fprintf(stderr, "\n");}
 enum {
   UDF_TASK_SETUP = 0,
   UDF_TASK_CALL = 1,
@@ -107,7 +104,7 @@ void* decodeUdfRequest(const void *buf, SUdfRequest* request);
 int32_t encodeUdfResponse(void **buf, const SUdfResponse *response);
 void* decodeUdfResponse(const void* buf, SUdfResponse *response);
 
-void freeUdfColumnData(SUdfColumnData *data);
+void freeUdfColumnData(SUdfColumnData *data, SUdfColumnMeta *meta);
 void freeUdfColumn(SUdfColumn* col);
 void freeUdfDataDataBlock(SUdfDataBlock *block);
 
diff --git a/source/libs/function/src/tudf.c b/source/libs/function/src/tudf.c
index 9aac2bfe0cce2587f3c45ed9957afac40ed746dd..5b1573c88f91bc2d4dd0aa95f0053dc443dfea0e 100644
--- a/source/libs/function/src/tudf.c
+++ b/source/libs/function/src/tudf.c
@@ -481,8 +481,8 @@ void* decodeUdfResponse(const void* buf, SUdfResponse* rsp) {
   return (void*)buf;
 }
 
-void freeUdfColumnData(SUdfColumnData *data) {
-  if (data->varLengthColumn) {
+void freeUdfColumnData(SUdfColumnData *data, SUdfColumnMeta *meta) {
+  if (IS_VAR_DATA_TYPE(meta->type)) {
     taosMemoryFree(data->varLenCol.varOffsets);
     data->varLenCol.varOffsets = NULL;
     taosMemoryFree(data->varLenCol.payload);
@@ -496,7 +496,7 @@ void freeUdfColumnData(SUdfColumnData *data) {
 }
 
 void freeUdfColumn(SUdfColumn* col) {
-  freeUdfColumnData(&col->colData);
+  freeUdfColumnData(&col->colData, &col->colMeta);
 }
 
 void freeUdfDataDataBlock(SUdfDataBlock *block) {
@@ -528,8 +528,7 @@ int32_t convertDataBlockToUdfDataBlock(SSDataBlock *block, SUdfDataBlock *udfBlo
     udfCol->colMeta.scale = col->info.scale;
     udfCol->colMeta.precision = col->info.precision;
     udfCol->colData.numOfRows = udfBlock->numOfRows;
-    udfCol->colData.varLengthColumn = IS_VAR_DATA_TYPE(udfCol->colMeta.type);
-    if (udfCol->colData.varLengthColumn) {
+    if (IS_VAR_DATA_TYPE(udfCol->colMeta.type)) {
       udfCol->colData.varLenCol.varOffsetsLen = sizeof(int32_t) * udfBlock->numOfRows;
       udfCol->colData.varLenCol.varOffsets = taosMemoryMalloc(udfCol->colData.varLenCol.varOffsetsLen);
       memcpy(udfCol->colData.varLenCol.varOffsets, col->varmeta.offset, udfCol->colData.varLenCol.varOffsetsLen);
@@ -555,7 +554,7 @@ int32_t convertDataBlockToUdfDataBlock(SSDataBlock *block, SUdfDataBlock *udfBlo
 int32_t convertUdfColumnToDataBlock(SUdfColumn *udfCol, SSDataBlock *block) {
   block->info.numOfCols = 1;
   block->info.rows = udfCol->colData.numOfRows;
-  block->info.hasVarCol = udfCol->colData.varLengthColumn;
+  block->info.hasVarCol = IS_VAR_DATA_TYPE(udfCol->colMeta.type);
 
   block->pDataBlock = taosArrayInit(1, sizeof(SColumnInfoData));
   taosArraySetSize(block->pDataBlock, 1);
diff --git a/source/libs/function/src/udfd.c b/source/libs/function/src/udfd.c
index 06fa49e1c2d85b123522efe1fc7a2cf8880a5fa6..ba9fca2969bf6d114936822113173155e93af4e4 100644
--- a/source/libs/function/src/udfd.c
+++ b/source/libs/function/src/udfd.c
@@ -75,8 +75,8 @@ typedef struct SUdf {
   char   path[PATH_MAX];
 
   uv_lib_t              lib;
+
   TUdfScalarProcFunc    scalarProcFunc;
-  TUdfFreeUdfColumnFunc freeUdfColumn;
 
   TUdfAggStartFunc      aggStartFunc;
   TUdfAggProcessFunc    aggProcFunc;
@@ -106,11 +106,6 @@ int32_t udfdLoadUdf(char *udfName, SUdf *udf) {
     char processFuncName[TSDB_FUNC_NAME_LEN] = {0};
     strcpy(processFuncName, udfName);
     uv_dlsym(&udf->lib, processFuncName, (void **)(&udf->scalarProcFunc));
-    char  freeFuncName[TSDB_FUNC_NAME_LEN + 5] = {0};
-    char *freeSuffix = "_free";
-    strncpy(freeFuncName, processFuncName, strlen(processFuncName));
-    strncat(freeFuncName, freeSuffix, strlen(freeSuffix));
-    uv_dlsym(&udf->lib, freeFuncName, (void **)(&udf->freeUdfColumn));
   } else if (udf->funcType == TSDB_FUNC_TYPE_AGGREGATE) {
     char processFuncName[TSDB_FUNC_NAME_LEN] = {0};
     strcpy(processFuncName, udfName);
@@ -215,7 +210,7 @@ void udfdProcessRequest(uv_work_t *req) {
           udf->scalarProcFunc(&input, &output);
 
           convertUdfColumnToDataBlock(&output, &response.callRsp.resultData);
-          udf->freeUdfColumn(&output);
+          freeUdfColumn(&output);
           break;
         }
         case TSDB_UDF_CALL_AGG_INIT: {
diff --git a/source/libs/function/test/udf1.c b/source/libs/function/test/udf1.c
index b2367313ae2fbada9f3cc4abb30b5d1cca8a3c88..4384d326cbbdc64f9713c03f75d625707cb22809 100644
--- a/source/libs/function/test/udf1.c
+++ b/source/libs/function/test/udf1.c
@@ -18,52 +18,20 @@ int32_t udf1_destroy() {
 }
 
 int32_t udf1(SUdfDataBlock* block, SUdfColumn *resultCol) {
-  SUdfColumnData *resultData = &resultCol->colData;
-  resultData->numOfRows = block->numOfRows;
-  SUdfColumnData *srcData = &block->udfCols[0]->colData;
-  resultData->varLengthColumn = srcData->varLengthColumn;
-
-  if (resultData->varLengthColumn) {
-    resultData->varLenCol.varOffsetsLen = srcData->varLenCol.varOffsetsLen;
-    resultData->varLenCol.varOffsets = malloc(resultData->varLenCol.varOffsetsLen);
-    memcpy(resultData->varLenCol.varOffsets, srcData->varLenCol.varOffsets, srcData->varLenCol.varOffsetsLen);
-
-    resultData->varLenCol.payloadLen = srcData->varLenCol.payloadLen;
-    resultData->varLenCol.payload = malloc(resultData->varLenCol.payloadLen);
-    memcpy(resultData->varLenCol.payload, srcData->varLenCol.payload, srcData->varLenCol.payloadLen);
-  } else {
-    resultData->fixLenCol.nullBitmapLen = srcData->fixLenCol.nullBitmapLen;
-    resultData->fixLenCol.nullBitmap = malloc(resultData->fixLenCol.nullBitmapLen);
-    memcpy(resultData->fixLenCol.nullBitmap, srcData->fixLenCol.nullBitmap, srcData->fixLenCol.nullBitmapLen);
-
-    resultData->fixLenCol.dataLen = srcData->fixLenCol.dataLen;
-    resultData->fixLenCol.data = malloc(resultData->fixLenCol.dataLen);
-    memcpy(resultData->fixLenCol.data, srcData->fixLenCol.data, srcData->fixLenCol.dataLen);
-    for (int32_t i = 0; i < resultData->numOfRows; ++i) {
-      *(resultData->fixLenCol.data + i * sizeof(int32_t)) = 88;
-    }
-  }
-
   SUdfColumnMeta *meta = &resultCol->colMeta;
   meta->bytes = 4;
   meta->type = TSDB_DATA_TYPE_INT;
   meta->scale = 0;
   meta->precision = 0;
-  return 0;
-}
 
-int32_t udf1_free(SUdfColumn *col) {
-  SUdfColumnData *data = &col->colData;
-  if (data->varLengthColumn) {
-    free(data->varLenCol.varOffsets);
-    data->varLenCol.varOffsets = NULL;
-    free(data->varLenCol.payload);
-    data->varLenCol.payload = NULL;
-  } else {
-    free(data->fixLenCol.nullBitmap);
-    data->fixLenCol.nullBitmap = NULL;
-    free(data->fixLenCol.data);
-    data->fixLenCol.data = NULL;
+  SUdfColumnData *resultData = &resultCol->colData;
+  resultData->numOfRows = block->numOfRows;
+  SUdfColumnData *srcData = &block->udfCols[0]->colData;
+
+  for (int32_t i = 0; i < resultData->numOfRows; ++i) {
+    int32_t luckyNum = 88;
+    udfColSetRow(resultCol, i, (char*)&luckyNum, false);
   }
+
   return 0;
 }
\ No newline at end of file