diff --git a/include/common/tcommon.h b/include/common/tcommon.h
index 2f93f8c3e3..d2352e100c 100644
--- a/include/common/tcommon.h
+++ b/include/common/tcommon.h
@@ -231,6 +231,7 @@ typedef struct SColumnInfoData {
   };
   SColumnInfo info;     // column info
   bool        hasNull;  // if current column data has null value.
+  bool        reassigned; // if current column data is reassigned.
 } SColumnInfoData;
 
 typedef struct SQueryTableDataCond {
diff --git a/include/common/tdatablock.h b/include/common/tdatablock.h
index 33c571fc1b..53fc07c3f3 100644
--- a/include/common/tdatablock.h
+++ b/include/common/tdatablock.h
@@ -178,6 +178,7 @@ int32_t getJsonValueLen(const char* data);
 
 int32_t colDataSetVal(SColumnInfoData* pColumnInfoData, uint32_t rowIndex, const char* pData, bool isNull);
 int32_t colDataAppend(SColumnInfoData* pColumnInfoData, uint32_t rowIndex, const char* pData, bool isNull);
+int32_t colDataReassignVal(SColumnInfoData* pColumnInfoData, uint32_t dstRowIdx, uint32_t srcRowIdx, const char* pData);
 int32_t colDataSetNItems(SColumnInfoData* pColumnInfoData, uint32_t rowIndex, const char* pData, uint32_t numOfRows, bool trimValue);
 int32_t colDataMergeCol(SColumnInfoData* pColumnInfoData, int32_t numOfRow1, int32_t* capacity,
                         const SColumnInfoData* pSource, int32_t numOfRow2);
diff --git a/source/common/src/tdatablock.c b/source/common/src/tdatablock.c
index 311c79381c..24e978b0ea 100644
--- a/source/common/src/tdatablock.c
+++ b/source/common/src/tdatablock.c
@@ -23,6 +23,20 @@
 
 int32_t colDataGetLength(const SColumnInfoData* pColumnInfoData, int32_t numOfRows) {
   if (IS_VAR_DATA_TYPE(pColumnInfoData->info.type)) {
+    if (pColumnInfoData->reassigned) {
+      int32_t totalSize = 0;
+      for (int32_t row = 0; row < numOfRows; ++row) {
+        char* pColData = pColumnInfoData->pData + pColumnInfoData->varmeta.offset[row];
+        int32_t colSize = 0;
+        if (pColumnInfoData->info.type == TSDB_DATA_TYPE_JSON) {
+          colSize = getJsonValueLen(pColData);
+        } else {
+          colSize = varDataTLen(pColData);
+        }
+        totalSize += colSize;
+      }
+      return totalSize;
+    }
     return pColumnInfoData->varmeta.length;
   } else {
     if (pColumnInfoData->info.type == TSDB_DATA_TYPE_NULL) {
@@ -126,6 +140,29 @@ int32_t colDataSetVal(SColumnInfoData* pColumnInfoData, uint32_t rowIndex, const
   return 0;
 }
 
+int32_t colDataReassignVal(SColumnInfoData* pColumnInfoData, uint32_t dstRowIdx, uint32_t srcRowIdx, const char* pData) {
+  int32_t type = pColumnInfoData->info.type;
+  if (IS_VAR_DATA_TYPE(type)) {
+    int32_t dataLen = 0;
+    if (type == TSDB_DATA_TYPE_JSON) {
+      dataLen = getJsonValueLen(pData);
+    } else {
+      dataLen = varDataTLen(pData);
+    }
+
+    SVarColAttr* pAttr = &pColumnInfoData->varmeta;
+
+    pColumnInfoData->varmeta.offset[dstRowIdx] = pColumnInfoData->varmeta.offset[srcRowIdx];
+    pColumnInfoData->reassigned = true;
+  } else {
+    memcpy(pColumnInfoData->pData + pColumnInfoData->info.bytes * dstRowIdx, pData, pColumnInfoData->info.bytes);
+    colDataClearNull_f(pColumnInfoData->nullbitmap, dstRowIdx);
+  }
+
+  return 0;
+}
+
+
 int32_t colDataReserve(SColumnInfoData* pColumnInfoData, size_t newSize) {
   if (!IS_VAR_DATA_TYPE(pColumnInfoData->info.type)) {
     return TSDB_CODE_SUCCESS;
@@ -580,8 +617,22 @@ int32_t blockDataToBuf(char* buf, const SSDataBlock* pBlock) {
     *(int32_t*)pStart = dataSize;
     pStart += sizeof(int32_t);
 
-    memcpy(pStart, pCol->pData, dataSize);
-    pStart += dataSize;
+    if (pCol->reassigned && IS_VAR_DATA_TYPE(pCol->info.type)) {
+      for (int32_t row = 0; row < numOfRows; ++row) {
+        char* pColData = pCol->pData + pCol->varmeta.offset[row];
+        int32_t colSize = 0;
+        if (pCol->info.type == TSDB_DATA_TYPE_JSON) {
+          colSize = getJsonValueLen(pColData);
+        } else {
+          colSize = varDataTLen(pColData);
+        }
+        memcpy(pStart, pColData, colSize);
+        pStart += colSize;
+      }
+    } else {
+      memcpy(pStart, pCol->pData, dataSize);
+      pStart += dataSize;
+    }    
   }
 
   return 0;
@@ -1741,7 +1792,20 @@ int32_t tEncodeDataBlock(void** buf, const SSDataBlock* pBlock) {
     int32_t len = colDataGetLength(pColData, rows);
     tlen += taosEncodeFixedI32(buf, len);
 
-    tlen += taosEncodeBinary(buf, pColData->pData, len);
+    if (pColData->reassigned && IS_VAR_DATA_TYPE(pColData->info.type)) {
+      for (int32_t row = 0; row < rows; ++row) {
+        char* pData = pColData->pData + pColData->varmeta.offset[row];
+        int32_t colSize = 0;
+        if (pColData->info.type == TSDB_DATA_TYPE_JSON) {
+          colSize = getJsonValueLen(pData);
+        } else {
+          colSize = varDataTLen(pData);
+        }
+        tlen += taosEncodeBinary(buf, pData, colSize);
+      }
+    } else {
+      tlen += taosEncodeBinary(buf, pColData->pData, len);
+    }
   }
   return tlen;
 }
@@ -2502,12 +2566,29 @@ int32_t blockEncode(const SSDataBlock* pBlock, char* data, int32_t numOfCols) {
     data += metaSize;
     dataLen += metaSize;
 
-    colSizes[col] = colDataGetLength(pColRes, numOfRows);
-    dataLen += colSizes[col];
-    if (pColRes->pData != NULL) {
-      memmove(data, pColRes->pData, colSizes[col]);
+     if (pColRes->reassigned && IS_VAR_DATA_TYPE(pColRes->info.type)) {
+        colSizes[col] = 0;
+        for (int32_t row = 0; row < numOfRows; ++row) {
+          char* pColData = pColRes->pData + pColRes->varmeta.offset[row];
+          int32_t colSize = 0;
+          if (pColRes->info.type == TSDB_DATA_TYPE_JSON) {
+            colSize = getJsonValueLen(pColData);
+          } else {
+            colSize = varDataTLen(pColData);
+          }
+          colSizes[col] += colSize;
+          dataLen += colSize;
+          memmove(data, pColData, colSize);
+          data += colSize;
+        }
+    } else {
+      colSizes[col] = colDataGetLength(pColRes, numOfRows);
+      dataLen += colSizes[col];
+      if (pColRes->pData != NULL) {
+        memmove(data, pColRes->pData, colSizes[col]);
+      }
+      data += colSizes[col];
     }
-    data += colSizes[col];
 
     colSizes[col] = htonl(colSizes[col]);
 //    uError("blockEncode col bytes:%d, type:%d, size:%d, htonl size:%d", pColRes->info.bytes, pColRes->info.type, htonl(colSizes[col]), colSizes[col]);
diff --git a/source/libs/executor/src/executorInt.c b/source/libs/executor/src/executorInt.c
index 4f1a0254e4..fbc0512a26 100644
--- a/source/libs/executor/src/executorInt.c
+++ b/source/libs/executor/src/executorInt.c
@@ -562,7 +562,6 @@ void extractQualifiedTupleByFilterResult(SSDataBlock* pBlock, const SColumnInfoD
       int32_t numOfRows = 0;
       if (IS_VAR_DATA_TYPE(pDst->info.type)) {
         int32_t j = 0;
-        pDst->varmeta.length = 0;
 
         while (j < totalRows) {
           if (pIndicator[j] == 0) {
@@ -573,18 +572,8 @@ void extractQualifiedTupleByFilterResult(SSDataBlock* pBlock, const SColumnInfoD
           if (colDataIsNull_var(pDst, j)) {
             colDataSetNull_var(pDst, numOfRows);
           } else {
-            // fix address sanitizer error. p1 may point to memory that will change during realloc of colDataSetVal, first copy it to p2
             char* p1 = colDataGetVarData(pDst, j);
-            int32_t len = 0;
-            if (pDst->info.type == TSDB_DATA_TYPE_JSON) {
-              len = getJsonValueLen(p1);
-            } else {
-              len = varDataTLen(p1);
-            }
-            char* p2 = taosMemoryMalloc(len);
-            memcpy(p2, p1, len);
-            colDataSetVal(pDst, numOfRows, p2, false);
-            taosMemoryFree(p2);
+            colDataReassignVal(pDst, numOfRows, j, p1);
           }
           numOfRows += 1;
           j += 1;
diff --git a/source/libs/function/src/tudf.c b/source/libs/function/src/tudf.c
index 6b70422ac8..31a7dfdbc5 100644
--- a/source/libs/function/src/tudf.c
+++ b/source/libs/function/src/tudf.c
@@ -791,7 +791,21 @@ int32_t convertDataBlockToUdfDataBlock(SSDataBlock *block, SUdfDataBlock *udfBlo
       memcpy(udfCol->colData.varLenCol.varOffsets, col->varmeta.offset, udfCol->colData.varLenCol.varOffsetsLen);
       udfCol->colData.varLenCol.payloadLen = colDataGetLength(col, udfBlock->numOfRows);
       udfCol->colData.varLenCol.payload = taosMemoryMalloc(udfCol->colData.varLenCol.payloadLen);
-      memcpy(udfCol->colData.varLenCol.payload, col->pData, udfCol->colData.varLenCol.payloadLen);
+      if (col->reassigned) {
+        for (int32_t row = 0; row < udfCol->colData.numOfRows; ++row) {
+          char* pColData = col->pData + col->varmeta.offset[row];
+          int32_t colSize = 0;
+          if (col->info.type == TSDB_DATA_TYPE_JSON) {
+            colSize = getJsonValueLen(pColData);
+          } else {
+            colSize = varDataTLen(pColData);
+          }
+          memcpy(udfCol->colData.varLenCol.payload, pColData, colSize);
+          udfCol->colData.varLenCol.payload += colSize;
+        }
+      } else {
+        memcpy(udfCol->colData.varLenCol.payload, col->pData, udfCol->colData.varLenCol.payloadLen);
+      }
     } else {
       udfCol->colData.fixLenCol.nullBitmapLen = BitmapLen(udfCol->colData.numOfRows);
       int32_t bitmapLen = udfCol->colData.fixLenCol.nullBitmapLen;