diff --git a/include/util/tdef.h b/include/util/tdef.h
index ebfb7b696aa5d156dbfa1f07f74470c37c4c63f9..e66cc0b7bb7d4bd86927c43f1f701fdd7ffc538e 100644
--- a/include/util/tdef.h
+++ b/include/util/tdef.h
@@ -356,8 +356,8 @@ typedef enum ELogicConditionType {
 
 #define TSDB_DEFAULT_EXPLAIN_VERBOSE false
 
-#define TSDB_EXPLAIN_RESULT_ROW_SIZE    1024
-#define TSDB_EXPLAIN_RESULT_COLUMN_NAME "QUERY PLAN"
+#define TSDB_EXPLAIN_RESULT_ROW_SIZE    512
+#define TSDB_EXPLAIN_RESULT_COLUMN_NAME "QUERY_PLAN"
 
 #define TSDB_MAX_FIELD_LEN             16384
 #define TSDB_MAX_BINARY_LEN            (TSDB_MAX_FIELD_LEN - TSDB_KEYSIZE)  // keep 16384
diff --git a/source/client/test/clientTests.cpp b/source/client/test/clientTests.cpp
index f16baba0e7e9f2788bcdb697596f4887cba39afd..f9825c50ffaf77133702cf9b1afaae0242f5bbb5 100644
--- a/source/client/test/clientTests.cpp
+++ b/source/client/test/clientTests.cpp
@@ -780,31 +780,28 @@ TEST(testCase, async_api_test) {
 
   taos_query(pConn, "use test");
 
-  TAOS_RES* pRes = taos_query(pConn, "select * from t1");
-
-  taos_query(pConn, "alter table t1 add column b int");
-  pRes = taos_query(pConn, "insert into t1 values(now, 1, 2)");
+  TAOS_RES* pRes = taos_query(pConn, "desc abc1.tu");
   if (taos_errno(pRes) != 0) {
     printf("failed, reason:%s\n", taos_errstr(pRes));
   }
 
-//  int32_t n = 0;
-//  TAOS_ROW    pRow = NULL;
-//  TAOS_FIELD* pFields = taos_fetch_fields(pRes);
-//  int32_t     numOfFields = taos_num_fields(pRes);
-//
-//  char str[512] = {0};
-//  while ((pRow = taos_fetch_row(pRes)) != NULL) {
-//    int32_t* length = taos_fetch_lengths(pRes);
-//    for(int32_t i = 0; i < numOfFields; ++i) {
-//      printf("(%d):%d " , i, length[i]);
-//    }
-//    printf("\n");
-//
-//    int32_t code = taos_print_row(str, pRow, pFields, numOfFields);
-//    printf("%s\n", str);
-//    memset(str, 0, sizeof(str));
-//  }
+  int32_t n = 0;
+  TAOS_ROW    pRow = NULL;
+  TAOS_FIELD* pFields = taos_fetch_fields(pRes);
+  int32_t     numOfFields = taos_num_fields(pRes);
+
+  char str[512] = {0};
+  while ((pRow = taos_fetch_row(pRes)) != NULL) {
+    int32_t* length = taos_fetch_lengths(pRes);
+    for(int32_t i = 0; i < numOfFields; ++i) {
+      printf("(%d):%d " , i, length[i]);
+    }
+    printf("\n");
+
+    int32_t code = taos_print_row(str, pRow, pFields, numOfFields);
+    printf("%s\n", str);
+    memset(str, 0, sizeof(str));
+  }
 
   taos_query_a(pConn, "alter table test.m1 comment 'abcde' ", queryCallback, pConn);
   getchar();
diff --git a/source/common/src/tdatablock.c b/source/common/src/tdatablock.c
index 8c51f1d50c383593499de1999047974d46ee63fa..aee0e15a7be661bc700b0375436771a32b022696 100644
--- a/source/common/src/tdatablock.c
+++ b/source/common/src/tdatablock.c
@@ -1902,7 +1902,7 @@ void blockCompressEncode(const SSDataBlock* pBlock, char* data, int32_t* dataLen
   int32_t* colSizes = (int32_t*)data;
   data += numOfCols * sizeof(int32_t);
 
-  *dataLen = blockDataGetSerialMetaSize(numOfCols);;
+  *dataLen = blockDataGetSerialMetaSize(numOfCols);
 
   int32_t numOfRows = pBlock->info.rows;
   for (int32_t col = 0; col < numOfCols; ++col) {
diff --git a/source/libs/command/src/command.c b/source/libs/command/src/command.c
index 3034b4b02a293dd4cce91814bde367682db6ac8d..f330b7ce162f9c79189a66c0772fffbc96cb8dcc 100644
--- a/source/libs/command/src/command.c
+++ b/source/libs/command/src/command.c
@@ -28,91 +28,94 @@ static int32_t getSchemaBytes(const SSchema* pSchema) {
   }
 }
 
-// todo : to convert data according to SSDatablock
-static void buildRspData(const STableMeta* pMeta, char* pData) {
-  int32_t* payloadLen = (int32_t*) pData;
-  uint64_t* groupId = (uint64_t*)(pData + sizeof(int32_t));
+static SSDataBlock* buildDescResultDataBlock() {
+  SSDataBlock* pBlock = taosMemoryCalloc(1, sizeof(SSDataBlock));
+  pBlock->info.numOfCols = DESCRIBE_RESULT_COLS;
+  pBlock->info.hasVarCol = true;
 
-  int32_t* pColSizes = (int32_t*)(pData + sizeof(int32_t) + sizeof(uint64_t));
-  pData = (char*) pColSizes + DESCRIBE_RESULT_COLS * sizeof(int32_t);
+  pBlock->pDataBlock = taosArrayInit(4, sizeof(SColumnInfoData));
 
-  int32_t numOfRows = TABLE_TOTAL_COL_NUM(pMeta);
+  SColumnInfoData infoData = {0};
+  infoData.info.type = TSDB_DATA_TYPE_VARCHAR;
+  infoData.info.bytes = DESCRIBE_RESULT_FIELD_LEN;
 
-  // Field
-  int32_t* pOffset = (int32_t*)pData;
-  pData += numOfRows * sizeof(int32_t);
+  taosArrayPush(pBlock->pDataBlock, &infoData);
+
+  infoData.info.type = TSDB_DATA_TYPE_VARCHAR;
+  infoData.info.bytes = DESCRIBE_RESULT_TYPE_LEN;
+  taosArrayPush(pBlock->pDataBlock, &infoData);
+
+  infoData.info.type = TSDB_DATA_TYPE_INT;
+  infoData.info.bytes = tDataTypes[TSDB_DATA_TYPE_INT].bytes;;
+  taosArrayPush(pBlock->pDataBlock, &infoData);
+
+  infoData.info.type = TSDB_DATA_TYPE_VARCHAR;
+  infoData.info.bytes = DESCRIBE_RESULT_NOTE_LEN;
+  taosArrayPush(pBlock->pDataBlock, &infoData);
+
+  return pBlock;
+}
+
+static void setDescResultIntoDataBlock(SSDataBlock* pBlock, int32_t numOfRows, STableMeta* pMeta) {
+  blockDataEnsureCapacity(pBlock, numOfRows);
+  pBlock->info.rows = numOfRows;
+
+  // field
+  SColumnInfoData* pCol1 = taosArrayGet(pBlock->pDataBlock, 0);
+  char buf[DESCRIBE_RESULT_FIELD_LEN] = {0};
   for (int32_t i = 0; i < numOfRows; ++i) {
-    STR_TO_VARSTR(pData, pMeta->schema[i].name);
-    int16_t len = varDataTLen(pData);
-    pData += len;
-    *pOffset = pColSizes[0];
-    pOffset += 1;
-    pColSizes[0] += len;
+    STR_TO_VARSTR(buf, pMeta->schema[i].name);
+    colDataAppend(pCol1, i, buf, false);
   }
-  
+
   // Type
-  pOffset = (int32_t*)pData;
-  pData += numOfRows * sizeof(int32_t);
+  SColumnInfoData* pCol2 = taosArrayGet(pBlock->pDataBlock, 1);
   for (int32_t i = 0; i < numOfRows; ++i) {
-    STR_TO_VARSTR(pData, tDataTypes[pMeta->schema[i].type].name);
-    int16_t len = varDataTLen(pData);
-    pData += len;
-    *pOffset = pColSizes[1];
-    pOffset += 1;
-    pColSizes[1] += len;
+    STR_TO_VARSTR(buf, tDataTypes[pMeta->schema[i].type].name);
+    colDataAppend(pCol2, i, buf, false);
   }
 
   // Length
-  pData += BitmapLen(numOfRows);
+  SColumnInfoData* pCol3 = taosArrayGet(pBlock->pDataBlock, 2);
   for (int32_t i = 0; i < numOfRows; ++i) {
-    *(int32_t*)pData = getSchemaBytes(pMeta->schema + i);
-    pData += sizeof(int32_t);
+    int32_t bytes = getSchemaBytes(pMeta->schema + i);
+    colDataAppend(pCol3, i, (const char*)&bytes, false);
   }
-  pColSizes[2] = sizeof(int32_t) * numOfRows;
 
   // Note
-  pOffset = (int32_t*)pData;
-  pData += numOfRows * sizeof(int32_t);
+  SColumnInfoData* pCol4 = taosArrayGet(pBlock->pDataBlock, 3);
   for (int32_t i = 0; i < numOfRows; ++i) {
-    STR_TO_VARSTR(pData, i >= pMeta->tableInfo.numOfColumns ? "TAG" : "");
-    int16_t len = varDataTLen(pData);
-    pData += len;
-    *pOffset = pColSizes[3];
-    pOffset += 1;
-    pColSizes[3] += len;
-  }
-
-  for (int32_t i = 0; i < DESCRIBE_RESULT_COLS; ++i) {
-    pColSizes[i] = htonl(pColSizes[i]);
+    STR_TO_VARSTR(buf, i >= pMeta->tableInfo.numOfColumns ? "TAG" : "");
+    colDataAppend(pCol4, i, buf, false);
   }
-
-
-  *payloadLen = (int32_t)(pData - (char*)payloadLen);
-}
-
-static int32_t calcRspSize(const STableMeta* pMeta) {
-  int32_t numOfRows = TABLE_TOTAL_COL_NUM(pMeta);
-  return sizeof(SRetrieveTableRsp) + 
-      (numOfRows * sizeof(int32_t) + numOfRows * DESCRIBE_RESULT_FIELD_LEN) + 
-      (numOfRows * sizeof(int32_t) + numOfRows * DESCRIBE_RESULT_TYPE_LEN) +
-      (BitmapLen(numOfRows) + numOfRows * sizeof(int32_t)) + 
-      (numOfRows * sizeof(int32_t) + numOfRows * DESCRIBE_RESULT_NOTE_LEN) +
-      sizeof(int32_t) + sizeof(uint64_t);
 }
 
 static int32_t execDescribe(SNode* pStmt, SRetrieveTableRsp** pRsp) {
-  SDescribeStmt* pDesc = (SDescribeStmt*)pStmt;
-  *pRsp = taosMemoryCalloc(1, calcRspSize(pDesc->pMeta));
+  SDescribeStmt* pDesc = (SDescribeStmt*) pStmt;
+  int32_t numOfRows = TABLE_TOTAL_COL_NUM(pDesc->pMeta);
+
+  SSDataBlock* pBlock = buildDescResultDataBlock();
+  setDescResultIntoDataBlock(pBlock, numOfRows, pDesc->pMeta);
+
+  size_t rspSize = sizeof(SRetrieveTableRsp) + blockGetEncodeSize(pBlock);
+  *pRsp = taosMemoryCalloc(1, rspSize);
   if (NULL == *pRsp) {
     return TSDB_CODE_OUT_OF_MEMORY;
   }
+
   (*pRsp)->useconds = 0;
   (*pRsp)->completed = 1;
   (*pRsp)->precision = 0;
   (*pRsp)->compressed = 0;
   (*pRsp)->compLen = 0;
-  (*pRsp)->numOfRows = htonl(TABLE_TOTAL_COL_NUM(pDesc->pMeta));
-  buildRspData(pDesc->pMeta, (*pRsp)->data);
+  (*pRsp)->numOfRows = htonl(numOfRows);
+  (*pRsp)->numOfCols = htonl(DESCRIBE_RESULT_COLS);
+
+  int32_t len = 0;
+  blockCompressEncode(pBlock, (*pRsp)->data, &len, DESCRIBE_RESULT_COLS, false);
+  ASSERT(len == rspSize - sizeof(SRetrieveTableRsp));
+
+  blockDataDestroy(pBlock);
   return TSDB_CODE_SUCCESS;
 }
 
diff --git a/source/libs/command/src/explain.c b/source/libs/command/src/explain.c
index 99ff4d406c2c89ce6e44789fb7a3c88d6a2f69ca..56b041af40988184b5c34ceec9daba6666284604 100644
--- a/source/libs/command/src/explain.c
+++ b/source/libs/command/src/explain.c
@@ -13,6 +13,7 @@
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include "tdatablock.h"
 #include "commandInt.h"
 #include "plannodes.h"
 #include "query.h"
@@ -916,9 +917,32 @@ int32_t qExplainGetRspFromCtx(void *ctx, SRetrieveTableRsp **pRsp) {
     QRY_ERR_RET(TSDB_CODE_QRY_APP_ERROR);
   }
 
-  int32_t colNum = 1;
-  int32_t rspSize = sizeof(SRetrieveTableRsp) + sizeof(int32_t) + sizeof(uint64_t) + sizeof(int32_t) * colNum +
-                    sizeof(int32_t) * rowNum + pCtx->dataSize;
+  SSDataBlock *pBlock = taosMemoryCalloc(1, sizeof(SSDataBlock));
+  SColumnInfoData infoData = {0};
+  infoData.info.type  = TSDB_DATA_TYPE_VARCHAR;
+  infoData.info.bytes = TSDB_EXPLAIN_RESULT_ROW_SIZE;
+
+  pBlock->pDataBlock = taosArrayInit(1, sizeof(SColumnInfoData));
+  taosArrayPush(pBlock->pDataBlock, &infoData);
+
+  SColumnInfoData* pInfoData = taosArrayGet(pBlock->pDataBlock, 0);
+  pInfoData->hasNull = false;
+  colInfoDataEnsureCapacity(pInfoData, 0, rowNum);
+
+  char buf[1024] = {0};
+  for (int32_t i = 0; i < rowNum; ++i) {
+    SQueryExplainRowInfo *row = taosArrayGet(pCtx->rows, i);
+    varDataCopy(buf, row->buf);
+    ASSERT(varDataTLen(row->buf) == row->len);
+    colDataAppend(pInfoData, i, buf, false);
+  }
+
+  pBlock->info.numOfCols = 1;
+  pBlock->info.rows = rowNum;
+  pBlock->info.hasVarCol = true;
+
+  int32_t rspSize = sizeof(SRetrieveTableRsp) + blockGetEncodeSize(pBlock);
+
   SRetrieveTableRsp *rsp = (SRetrieveTableRsp *)taosMemoryCalloc(1, rspSize);
   if (NULL == rsp) {
     qError("malloc SRetrieveTableRsp failed, size:%d", rspSize);
@@ -928,34 +952,13 @@ int32_t qExplainGetRspFromCtx(void *ctx, SRetrieveTableRsp **pRsp) {
   rsp->completed = 1;
   rsp->numOfRows = htonl(rowNum);
 
-  // payload length
-  *(int32_t *)rsp->data =
-      sizeof(int32_t) + sizeof(uint64_t) + sizeof(int32_t) * colNum + sizeof(int32_t) * rowNum + pCtx->dataSize;
+  int32_t len = 0;
+  blockCompressEncode(pBlock, rsp->data, &len, pBlock->info.numOfCols, 0);
+  ASSERT(len == rspSize - sizeof(SRetrieveTableRsp));
 
-  // group id
-  *(uint64_t *)(rsp->data + sizeof(int32_t)) = 0;
-
-  // column length
-  int32_t *colLength = (int32_t *)(rsp->data + sizeof(int32_t) + sizeof(uint64_t));
-
-  // varchar column offset segment
-  int32_t *offset = (int32_t *)((char *)colLength + sizeof(int32_t));
-
-  // varchar data real payload
-  char *data = (char *)(offset + rowNum);
-
-  char *start = data;
-  for (int32_t i = 0; i < rowNum; ++i) {
-    SQueryExplainRowInfo *row = taosArrayGet(pCtx->rows, i);
-    offset[i] = data - start;
-
-    varDataCopy(data, row->buf);
-    ASSERT(varDataTLen(row->buf) == row->len);
-    data += row->len;
-  }
+  rsp->compLen = htonl(len);
 
-  *colLength = htonl(data - start);
-  rsp->compLen = htonl(rspSize);
+  blockDataDestroy(pBlock);
 
   *pRsp = rsp;
   return TSDB_CODE_SUCCESS;