diff --git a/include/common/tmsg.h b/include/common/tmsg.h
index cd16bbf862..4cfcf0e888 100644
--- a/include/common/tmsg.h
+++ b/include/common/tmsg.h
@@ -915,6 +915,12 @@ typedef struct {
   char    data[];
 } SRetrieveMetaTableRsp;
 
+typedef struct {
+  int32_t numOfItems;
+  char    data[];
+} SExplainRsp;
+
+
 typedef struct {
   char    fqdn[TSDB_FQDN_LEN];  // end point, hostname:port
   int32_t port;
@@ -1052,6 +1058,7 @@ typedef struct SSubQueryMsg {
   uint64_t taskId;
   int64_t  refId;
   int8_t   taskType;
+  int8_t   explain;
   uint32_t sqlLen;  // the query sql,
   uint32_t phyLen;
   char     msg[];
diff --git a/include/common/tmsgdef.h b/include/common/tmsgdef.h
index 36a489eb59..1d4667cda0 100644
--- a/include/common/tmsgdef.h
+++ b/include/common/tmsgdef.h
@@ -188,6 +188,7 @@ enum {
   TD_DEF_MSG_TYPE(TDMT_VND_SHOW_TABLES_FETCH, "vnode-show-tables-fetch", SVShowTablesFetchReq, SVShowTablesFetchRsp)
   TD_DEF_MSG_TYPE(TDMT_VND_QUERY_CONTINUE, "vnode-query-continue", NULL, NULL)
   TD_DEF_MSG_TYPE(TDMT_VND_QUERY_HEARTBEAT, "vnode-query-heartbeat", NULL, NULL)
+  TD_DEF_MSG_TYPE(TDMT_VND_EXPLAIN, "vnode-explain", NULL, NULL)
 
   TD_DEF_MSG_TYPE(TDMT_VND_SUBSCRIBE, "vnode-subscribe", SMVSubscribeReq, SMVSubscribeRsp)
   TD_DEF_MSG_TYPE(TDMT_VND_CONSUME, "vnode-consume", SMqCVConsumeReq, SMqCVConsumeRsp)
diff --git a/include/libs/command/command.h b/include/libs/command/command.h
index 7e58d39692..31e370ac5c 100644
--- a/include/libs/command/command.h
+++ b/include/libs/command/command.h
@@ -17,8 +17,20 @@
 #include "tmsg.h"
 #include "plannodes.h"
 
+typedef struct SExplainCtx SExplainCtx;
+
+typedef struct SExplainExecInfo {
+  uint64_t startupCost;
+  uint64_t totalCost;
+  uint64_t numOfRows;
+} SExplainExecInfo;
+
 int32_t qExecCommand(SNode* pStmt, SRetrieveTableRsp** pRsp);
 
 int32_t qExecStaticExplain(SQueryPlan *pDag, SRetrieveTableRsp **pRsp);
+int32_t qExecExplainBegin(SQueryPlan *pDag, SExplainCtx **pCtx, int32_t startTs);
+int32_t qExecExplainEnd(SExplainCtx *pCtx);
+int32_t qExplainUpdateExecInfo(SExplainCtx        *pCtx, SExplainRsp *pRspMsg, int32_t groupId, SRetrieveTableRsp **pRsp);
+void    qExplainFreeCtx(SExplainCtx *pCtx);
 
 
diff --git a/include/libs/executor/executor.h b/include/libs/executor/executor.h
index d3cd828cf5..4d289147d0 100644
--- a/include/libs/executor/executor.h
+++ b/include/libs/executor/executor.h
@@ -174,6 +174,8 @@ void** qReleaseTask(void* pMgmt, void* pQInfo, bool freeHandle);
 
 void qProcessFetchRsp(void* parent, struct SRpcMsg* pMsg, struct SEpSet* pEpSet);
 
+int32_t qGetExplainExecInfo(qTaskInfo_t tinfo, int32_t *resNum, SExplainExecInfo **pRes);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/include/libs/nodes/nodes.h b/include/libs/nodes/nodes.h
index 9849dfca39..2979040c07 100644
--- a/include/libs/nodes/nodes.h
+++ b/include/libs/nodes/nodes.h
@@ -216,6 +216,7 @@ int32_t nodesListToString(const SNodeList* pList, bool format, char** pStr, int3
 int32_t nodesStringToList(const char* pStr, SNodeList** pList);
 
 int32_t nodesNodeToSQL(SNode *pNode, char *buf, int32_t bufSize, int32_t *len);
+char *nodesGetNameFromColumnNode(SNode *pNode);
 
 #ifdef __cplusplus
 }
diff --git a/include/libs/nodes/plannodes.h b/include/libs/nodes/plannodes.h
index 37163f60dd..eda7882e2c 100644
--- a/include/libs/nodes/plannodes.h
+++ b/include/libs/nodes/plannodes.h
@@ -308,6 +308,7 @@ typedef enum EExplainMode {
 typedef struct SExplainInfo {
   EExplainMode mode;
   bool verbose;
+  double ratio;
 } SExplainInfo;
 
 typedef struct SQueryPlan {
diff --git a/include/libs/nodes/querynodes.h b/include/libs/nodes/querynodes.h
index ddcbaa0bee..04fa8f21df 100644
--- a/include/libs/nodes/querynodes.h
+++ b/include/libs/nodes/querynodes.h
@@ -315,6 +315,7 @@ bool nodesIsTimelineQuery(const SNode* pQuery);
 
 void* nodesGetValueFromNode(SValueNode *pNode);
 char* nodesGetStrValueFromNode(SValueNode *pNode);
+char *getFillModeString(EFillMode mode);
 
 #ifdef __cplusplus
 }
diff --git a/include/libs/scheduler/scheduler.h b/include/libs/scheduler/scheduler.h
index 16a6ae32cf..5ab4ead89c 100644
--- a/include/libs/scheduler/scheduler.h
+++ b/include/libs/scheduler/scheduler.h
@@ -71,7 +71,7 @@ int32_t schedulerInit(SSchedulerCfg *cfg);
  * @param nodeList  Qnode/Vnode address list, element is SQueryNodeAddr
  * @return
  */
-int32_t schedulerExecJob(void *transport, SArray *nodeList, SQueryPlan* pDag, int64_t* pJob, const char* sql, SQueryResult *pRes);
+int32_t schedulerExecJob(void *transport, SArray *nodeList, SQueryPlan *pDag, int64_t *pJob, const char *sql, int64_t startTs, SQueryResult *pRes);
 
 /**
  * Process the query job, generated according to the query physical plan.
diff --git a/source/client/src/clientImpl.c b/source/client/src/clientImpl.c
index 8cd53f18b0..1512322f1a 100644
--- a/source/client/src/clientImpl.c
+++ b/source/client/src/clientImpl.c
@@ -241,7 +241,7 @@ int32_t scheduleQuery(SRequestObj* pRequest, SQueryPlan* pDag, SArray* pNodeList
   void* pTransporter = pRequest->pTscObj->pAppInfo->pTransporter;
 
   SQueryResult res = {.code = 0, .numOfRows = 0, .msgSize = ERROR_MSG_BUF_DEFAULT_SIZE, .msg = pRequest->msgBuf};
-  int32_t      code = schedulerExecJob(pTransporter, pNodeList, pDag, &pRequest->body.queryJob, pRequest->sqlstr, &res);
+  int32_t      code = schedulerExecJob(pTransporter, pNodeList, pDag, &pRequest->body.queryJob, pRequest->sqlstr, pRequest->metric.start, &res);
   if (code != TSDB_CODE_SUCCESS) {
     if (pRequest->body.queryJob != 0) {
       schedulerFreeJob(pRequest->body.queryJob);
diff --git a/source/libs/command/inc/commandInt.h b/source/libs/command/inc/commandInt.h
index 771baca2ab..de0a7c433a 100644
--- a/source/libs/command/inc/commandInt.h
+++ b/source/libs/command/inc/commandInt.h
@@ -50,8 +50,9 @@ extern "C" {
 
 typedef struct SExplainGroup {
   int32_t   nodeNum;
+  SRWLatch  lock;
   SSubplan *plan;
-  void     *execInfo;  //TODO
+  SArray   *execInfo;
 } SExplainGroup;
 
 typedef struct SExplainResNode {
@@ -67,10 +68,18 @@ typedef struct SQueryExplainRowInfo {
 } SQueryExplainRowInfo;
 
 typedef struct SExplainCtx {
-  int32_t   totalSize;
+  double    ratio;
   bool      verbose;
+
+  int32_t   rootGroupId;
+  int32_t   dataSize;
+  bool      execDone;
+  int64_t   reqStartTs;
+  int64_t   jobStartTs;
+  int64_t   jobDoneTs;
   char     *tbuf;
   SArray   *rows;
+  int32_t   groupDoneNum;
   SHashObj *groupHash;
 } SExplainCtx;
 
diff --git a/source/libs/command/src/explain.c b/source/libs/command/src/explain.c
index 847a863e76..4bf354dee5 100644
--- a/source/libs/command/src/explain.c
+++ b/source/libs/command/src/explain.c
@@ -17,32 +17,31 @@
 #include "plannodes.h"
 #include "commandInt.h"
 
-int32_t qGenerateExplainResNode(SPhysiNode *pNode, void *pExecInfo, SExplainResNode **pRes);
-int32_t qAppendTaskExplainResRows(void *pCtx, int32_t groupId, int32_t level);
+int32_t qExplainGenerateResNode(SPhysiNode *pNode, void *pExecInfo, SExplainResNode **pRes);
+int32_t qExplainAppendGroupResRows(void *pCtx, int32_t groupId, int32_t level);
 
 
-void qFreeExplainResTree(SExplainResNode *res) {
-  if (NULL == res) {
+void qExplainFreeResNode(SExplainResNode *resNode) {
+  if (NULL == resNode) {
     return;
   }
 
-  taosMemoryFreeClear(res->pExecInfo);
+  taosMemoryFreeClear(resNode->pExecInfo);
 
   SNode* node = NULL;
-  FOREACH(node, res->pChildren) {
-    qFreeExplainResTree((SExplainResNode *)node);
+  FOREACH(node, resNode->pChildren) {
+    qExplainFreeResNode((SExplainResNode *)node);
   }  
-  nodesClearList(res->pChildren);
+  nodesClearList(resNode->pChildren);
   
-  taosMemoryFreeClear(res);
+  taosMemoryFreeClear(resNode);
 }
 
-void qFreeExplainCtx(void *ctx) {
-  if (NULL == ctx) {
+void qExplainFreeCtx(SExplainCtx *pCtx) {
+  if (NULL == pCtx) {
     return;
   }
 
-  SExplainCtx *pCtx = (SExplainCtx *)ctx;
   int32_t rowSize = taosArrayGetSize(pCtx->rows);
   for (int32_t i = 0; i < rowSize; ++i) {
     SQueryExplainRowInfo *row = taosArrayGet(pCtx->rows, i);
@@ -54,7 +53,7 @@ void qFreeExplainCtx(void *ctx) {
   taosMemoryFree(pCtx);
 }
 
-int32_t qInitExplainCtx(void **pCtx, SHashObj *groupHash, bool verbose) {
+int32_t qExplainInitCtx(SExplainCtx **pCtx, SHashObj *groupHash, bool verbose, double ratio) {
   int32_t code = 0;
   SExplainCtx *ctx = taosMemoryCalloc(1, sizeof(SExplainCtx));
   if (NULL == ctx) {
@@ -75,6 +74,7 @@ int32_t qInitExplainCtx(void **pCtx, SHashObj *groupHash, bool verbose) {
   }
 
   ctx->verbose = verbose;
+  ctx->ratio = ratio;
   ctx->tbuf = tbuf;
   ctx->rows = rows;
   ctx->groupHash = groupHash;
@@ -92,35 +92,7 @@ _return:
   QRY_RET(code);
 }
 
-
-char *qFillModeString(EFillMode mode) {
-  switch (mode) {
-    case FILL_MODE_NONE:
-      return "none";
-    case FILL_MODE_VALUE:
-      return "value";
-    case FILL_MODE_PREV:
-      return "prev";
-    case FILL_MODE_NULL:
-      return "null";
-    case FILL_MODE_LINEAR:
-      return "linear";
-    case FILL_MODE_NEXT:
-      return "next";
-    default:
-      return "unknown";
-  }
-}
-
-char *qGetNameFromColumnNode(SNode *pNode) {
-  if (NULL == pNode || QUERY_NODE_COLUMN != pNode->type) {
-    return "NULL";
-  }
-  
-  return ((SColumnNode *)pNode)->colName;
-}
-
-int32_t qGenerateExplainResChildren(SPhysiNode *pNode, void *pExecInfo, SNodeList **pChildren) {
+int32_t qExplainGenerateResChildren(SPhysiNode *pNode, void *pExecInfo, SNodeList **pChildren) {
   int32_t tlen = 0;
   SNodeList *pPhysiChildren = NULL;
   
@@ -192,38 +164,38 @@ int32_t qGenerateExplainResChildren(SPhysiNode *pNode, void *pExecInfo, SNodeLis
   SNode* node = NULL;
   SExplainResNode *pResNode = NULL;
   FOREACH(node, pPhysiChildren) {
-    QRY_ERR_RET(qGenerateExplainResNode((SPhysiNode *)node, pExecInfo, &pResNode));
+    QRY_ERR_RET(qExplainGenerateResNode((SPhysiNode *)node, pExecInfo, &pResNode));
     QRY_ERR_RET(nodesListAppend(*pChildren, pResNode));
   }
 
   return TSDB_CODE_SUCCESS;
 }
 
-int32_t qGenerateExplainResNode(SPhysiNode *pNode, void *pExecInfo, SExplainResNode **pRes) {
+int32_t qExplainGenerateResNode(SPhysiNode *pNode, void *pExecInfo, SExplainResNode **pResNode) {
   if (NULL == pNode) {
-    *pRes = NULL;
+    *pResNode = NULL;
     qError("physical node is NULL");
     return TSDB_CODE_QRY_APP_ERROR;
   }
 
-  SExplainResNode *res = taosMemoryCalloc(1, sizeof(SExplainResNode));
-  if (NULL == res) {
+  SExplainResNode *resNode = taosMemoryCalloc(1, sizeof(SExplainResNode));
+  if (NULL == resNode) {
     qError("calloc SPhysiNodeExplainRes failed");
     return TSDB_CODE_QRY_OUT_OF_MEMORY;
   }
 
   int32_t code = 0;
-  res->pNode = pNode;
-  res->pExecInfo = pExecInfo;
-  QRY_ERR_JRET(qGenerateExplainResChildren(pNode, pExecInfo, &res->pChildren));
+  resNode->pNode = pNode;
+  resNode->pExecInfo = pExecInfo;
+  QRY_ERR_JRET(qExplainGenerateResChildren(pNode, pExecInfo, &resNode->pChildren));
   
-  *pRes = res;
+  *pResNode = resNode;
 
   return TSDB_CODE_SUCCESS;
 
 _return:
 
-  qFreeExplainResTree(res);
+  qExplainFreeResNode(resNode);
   
   QRY_RET(code);
 }
@@ -249,7 +221,7 @@ int32_t qExplainResAppendRow(SExplainCtx *ctx, char *tbuf, int32_t len, int32_t
   memcpy(row.buf, tbuf, len);
   row.level = level;
   row.len = len;
-  ctx->totalSize += len;
+  ctx->dataSize += len;
 
   if (NULL == taosArrayPush(ctx->rows, &row)) {
     qError("taosArrayPush row to explain res rows failed");
@@ -444,7 +416,7 @@ int32_t qExplainResNodeToRowsImpl(SExplainResNode *pResNode, SExplainCtx *ctx, i
         }
       }
 
-      QRY_ERR_RET(qAppendTaskExplainResRows(ctx, pExchNode->srcGroupId, level + 1));
+      QRY_ERR_RET(qExplainAppendGroupResRows(ctx, pExchNode->srcGroupId, level + 1));
       break;
     }
     case QUERY_NODE_PHYSICAL_PLAN_SORT:{
@@ -468,7 +440,7 @@ int32_t qExplainResNodeToRowsImpl(SExplainResNode *pResNode, SExplainCtx *ctx, i
     }
     case QUERY_NODE_PHYSICAL_PLAN_INTERVAL:{
       SIntervalPhysiNode *pIntNode = (SIntervalPhysiNode *)pNode;
-      EXPLAIN_ROW_NEW(level, EXPLAIN_INTERVAL_FORMAT, qGetNameFromColumnNode(pIntNode->pTspk), pIntNode->window.pFuncs->length, 
+      EXPLAIN_ROW_NEW(level, EXPLAIN_INTERVAL_FORMAT, nodesGetNameFromColumnNode(pIntNode->pTspk), pIntNode->window.pFuncs->length, 
         INVERAL_TIME_FROM_PRECISION_TO_UNIT(pIntNode->interval, pIntNode->intervalUnit, pIntNode->precision), pIntNode->intervalUnit, 
         pIntNode->offset, getPrecisionUnit(pIntNode->precision), 
         INVERAL_TIME_FROM_PRECISION_TO_UNIT(pIntNode->sliding, pIntNode->slidingUnit, pIntNode->precision), pIntNode->slidingUnit, 
@@ -481,7 +453,7 @@ int32_t qExplainResNodeToRowsImpl(SExplainResNode *pResNode, SExplainCtx *ctx, i
 
       if (verbose) {
         if (pIntNode->pFill) {
-          EXPLAIN_ROW_NEW(level + 1, EXPLAIN_FILL_FORMAT, qFillModeString(pIntNode->pFill->mode));      
+          EXPLAIN_ROW_NEW(level + 1, EXPLAIN_FILL_FORMAT, getFillModeString(pIntNode->pFill->mode));      
           EXPLAIN_ROW_END();
           QRY_ERR_RET(qExplainResAppendRow(ctx, tbuf, tlen, level + 1));
         }
@@ -540,7 +512,7 @@ int32_t qExplainResNodeToRows(SExplainResNode *pResNode, SExplainCtx *ctx, int32
   return TSDB_CODE_SUCCESS;
 }
 
-int32_t qAppendTaskExplainResRows(void *pCtx, int32_t groupId, int32_t level) {
+int32_t qExplainAppendGroupResRows(void *pCtx, int32_t groupId, int32_t level) {
   SExplainResNode *node = NULL;
   int32_t code = 0;
   SExplainCtx *ctx = (SExplainCtx *)pCtx;
@@ -551,19 +523,19 @@ int32_t qAppendTaskExplainResRows(void *pCtx, int32_t groupId, int32_t level) {
     QRY_ERR_RET(TSDB_CODE_QRY_APP_ERROR);
   }
   
-  QRY_ERR_RET(qGenerateExplainResNode(group->plan->pNode, group->execInfo, &node));
+  QRY_ERR_RET(qExplainGenerateResNode(group->plan->pNode, group->execInfo, &node));
 
   QRY_ERR_JRET(qExplainResNodeToRows(node, ctx, level));
 
 _return:
 
-  qFreeExplainResTree(node);
+  qExplainFreeResNode(node);
   
   QRY_RET(code);
 }
 
 
-int32_t qGetExplainRspFromCtx(void *ctx, SRetrieveTableRsp **pRsp) {
+int32_t qExplainGetRspFromCtx(void *ctx, SRetrieveTableRsp **pRsp) {
   SExplainCtx *pCtx = (SExplainCtx *)ctx;
   int32_t rowNum = taosArrayGetSize(pCtx->rows);
   if (rowNum <= 0) {
@@ -572,7 +544,7 @@ int32_t qGetExplainRspFromCtx(void *ctx, SRetrieveTableRsp **pRsp) {
   }
   
   int32_t colNum = 1;
-  int32_t rspSize = sizeof(SRetrieveTableRsp) + sizeof(int32_t) * colNum + sizeof(int32_t) * rowNum + pCtx->totalSize;
+  int32_t rspSize = sizeof(SRetrieveTableRsp) + sizeof(int32_t) * colNum + sizeof(int32_t) * rowNum + pCtx->dataSize;
   SRetrieveTableRsp *rsp = (SRetrieveTableRsp *)taosMemoryCalloc(1, rspSize);
   if (NULL == rsp) {
     qError("malloc SRetrieveTableRsp failed, size:%d", rspSize);
@@ -582,7 +554,7 @@ int32_t qGetExplainRspFromCtx(void *ctx, SRetrieveTableRsp **pRsp) {
   rsp->completed = 1;
   rsp->numOfRows = htonl(rowNum);
 
-  *(int32_t *)rsp->data = htonl(pCtx->totalSize);
+  *(int32_t *)rsp->data = htonl(pCtx->dataSize);
 
   int32_t *offset = (int32_t *)((char *)rsp->data + sizeof(int32_t));
   char *data = (char *)(offset + rowNum);
@@ -604,13 +576,13 @@ int32_t qGetExplainRspFromCtx(void *ctx, SRetrieveTableRsp **pRsp) {
   return TSDB_CODE_SUCCESS;
 }
 
-int32_t qExecStaticExplain(SQueryPlan *pDag, SRetrieveTableRsp **pRsp) {
+
+int32_t qExplainPrepareCtx(SQueryPlan *pDag, SExplainCtx **pCtx) {
   int32_t code = 0;
   SNodeListNode *plans = NULL;
   int32_t        taskNum = 0;
   SExplainGroup *pGroup = NULL;
-  void *pCtx = NULL;
-  int32_t rootGroupId = 0;
+  SExplainCtx *ctx = NULL;
 
   if (pDag->numOfSubplans <= 0) {
     qError("invalid subplan num:%d", pDag->numOfSubplans);
@@ -629,7 +601,7 @@ int32_t qExecStaticExplain(SQueryPlan *pDag, SRetrieveTableRsp **pRsp) {
     QRY_ERR_RET(TSDB_CODE_QRY_OUT_OF_MEMORY);
   }
 
-  QRY_ERR_JRET(qInitExplainCtx(&pCtx, groupHash, pDag->explainInfo.verbose));
+  QRY_ERR_JRET(qExplainInitCtx(&ctx, groupHash, pDag->explainInfo.verbose, pDag->explainInfo.ratio));
 
   for (int32_t i = 0; i < levelNum; ++i) {
     plans = (SNodeListNode *)nodesListGetNode(pDag->pSubplans, i);
@@ -666,22 +638,62 @@ int32_t qExecStaticExplain(SQueryPlan *pDag, SRetrieveTableRsp **pRsp) {
         QRY_ERR_JRET(TSDB_CODE_QRY_INVALID_INPUT);
       }
 
-      rootGroupId = plan->id.groupId;
+      ctx->rootGroupId = plan->id.groupId;
     }
 
     qDebug("level %d group handled, taskNum:%d", i, taskNum);
   }
 
-  QRY_ERR_JRET(qAppendTaskExplainResRows(pCtx, rootGroupId, 0));
-  
-  QRY_ERR_JRET(qGetExplainRspFromCtx(pCtx, pRsp));
+  *pCtx = ctx;
+
+  return TSDB_CODE_SUCCESS;
   
 _return:
 
-  qFreeExplainCtx(pCtx);
+  qExplainFreeCtx(ctx);
 
   QRY_RET(code);
 }
 
 
+int32_t qExplainUpdateExecInfo(SExplainCtx        *pCtx, SExplainRsp *pRspMsg, int32_t groupId, SRetrieveTableRsp **pRsp) {
+
+}
+
+
+int32_t qExecStaticExplain(SQueryPlan *pDag, SRetrieveTableRsp **pRsp) {
+  int32_t code = 0;
+  SExplainCtx *pCtx = NULL;
+
+  QRY_ERR_RET(qExplainPrepareCtx(pDag, &pCtx));
+
+  QRY_ERR_JRET(qExplainAppendGroupResRows(pCtx, pCtx->rootGroupId, 0));
+  
+  QRY_ERR_JRET(qExplainGetRspFromCtx(pCtx, pRsp));
+  
+_return:
+
+  qExplainFreeCtx(pCtx);
+
+  QRY_RET(code);
+}
+
+int32_t qExecExplainBegin(SQueryPlan *pDag, SExplainCtx **pCtx, int32_t startTs) {
+  QRY_ERR_RET(qExplainPrepareCtx(pDag, pCtx));
+  
+  (*pCtx)->reqStartTs = startTs;
+  (*pCtx)->jobStartTs = taosGetTimestampMs();
+
+  return TSDB_CODE_SUCCESS;
+}
+
+int32_t qExecExplainEnd(SExplainCtx *pCtx) {
+  pCtx->jobDoneTs = taosGetTimestampMs();
+  
+  atomic_store_8((int8_t *)&pCtx->execDone, true);
+
+  return TSDB_CODE_SUCCESS;
+}
+
+
 
diff --git a/source/libs/executor/src/executorMain.c b/source/libs/executor/src/executorMain.c
index 6d78fa835a..d7c99d54df 100644
--- a/source/libs/executor/src/executorMain.c
+++ b/source/libs/executor/src/executorMain.c
@@ -229,3 +229,12 @@ void qDestroyTask(qTaskInfo_t qTaskHandle) {
   queryCostStatis(pTaskInfo);   // print the query cost summary
   doDestroyTask(pTaskInfo);
 }
+
+int32_t qGetExplainExecInfo(qTaskInfo_t tinfo, int32_t *resNum, SExplainExecInfo **pRes) {
+  SExecTaskInfo *pTaskInfo = (SExecTaskInfo *)tinfo;
+  int32_t capacity = 0;
+
+  return getOperatorExplainExecInfo(pTaskInfo->pRoot, pRes, &capacity, resNum);  
+}
+
+
diff --git a/source/libs/executor/src/executorimpl.c b/source/libs/executor/src/executorimpl.c
index 169e47eb33..e423690740 100644
--- a/source/libs/executor/src/executorimpl.c
+++ b/source/libs/executor/src/executorimpl.c
@@ -9516,3 +9516,18 @@ void releaseQueryBuf(size_t numOfTables) {
   // restore value is not enough buffer available
   atomic_add_fetch_64(&tsQueryBufferSizeBytes, t);
 }
+
+int32_t getOperatorExplainExecInfo(SOperatorInfo *operator, SExplainExecInfo **pRes, int32_t *capacity, int32_t *resNum) {
+  if (*resNum >= *capacity) {
+    *capacity += 10;
+    
+    *pRes = taosMemoryRealloc(*pRes, (*capacity) * sizeof(SExplainExecInfo));
+    if (NULL == *pRes) {
+      qError("malloc %d failed", capacity * sizeof(SExplainExecInfo));
+      return TSDB_CODE_QRY_OUT_OF_MEMORY;
+    }
+  }
+
+}
+
+
diff --git a/source/libs/nodes/inc/nodesUtil.h b/source/libs/nodes/inc/nodesUtil.h
index 976044c16f..c6233ba980 100644
--- a/source/libs/nodes/inc/nodesUtil.h
+++ b/source/libs/nodes/inc/nodesUtil.h
@@ -31,6 +31,7 @@ extern "C" {
 #define NODES_RET(c) do { int32_t _code = c; if (_code != TSDB_CODE_SUCCESS) { terrno = _code; } return _code; } while (0)
 #define NODES_ERR_JRET(c) do { code = c; if (code != TSDB_CODE_SUCCESS) { terrno = code; goto _return; } } while (0)
 
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/source/libs/nodes/src/nodesUtilFuncs.c b/source/libs/nodes/src/nodesUtilFuncs.c
index 732d9acfbe..812fa333b6 100644
--- a/source/libs/nodes/src/nodesUtilFuncs.c
+++ b/source/libs/nodes/src/nodesUtilFuncs.c
@@ -1023,3 +1023,33 @@ int32_t nodesCollectFuncs(SSelectStmt* pSelect, FFuncClassifier classifier, SNod
   
   return TSDB_CODE_SUCCESS;
 }
+
+
+char *getFillModeString(EFillMode mode) {
+  switch (mode) {
+    case FILL_MODE_NONE:
+      return "none";
+    case FILL_MODE_VALUE:
+      return "value";
+    case FILL_MODE_PREV:
+      return "prev";
+    case FILL_MODE_NULL:
+      return "null";
+    case FILL_MODE_LINEAR:
+      return "linear";
+    case FILL_MODE_NEXT:
+      return "next";
+    default:
+      return "unknown";
+  }
+}
+
+char *nodesGetNameFromColumnNode(SNode *pNode) {
+  if (NULL == pNode || QUERY_NODE_COLUMN != pNode->type) {
+    return "NULL";
+  }
+  
+  return ((SColumnNode *)pNode)->colName;
+}
+
+
diff --git a/source/libs/qworker/inc/qworkerInt.h b/source/libs/qworker/inc/qworkerInt.h
index 573eaed2e6..cfd4a3ec7b 100644
--- a/source/libs/qworker/inc/qworkerInt.h
+++ b/source/libs/qworker/inc/qworkerInt.h
@@ -107,15 +107,17 @@ typedef struct SQWTaskCtx {
   SRWLatch        lock;
   int8_t          phase;
   int8_t          taskType;
+  int8_t          explain;
   
-  bool            emptyRes;
   bool            queryFetched;
   bool            queryEnd;
   bool            queryContinue;
   bool            queryInQueue;
   int32_t         rspCode; 
 
-  SQWConnInfo     connInfo;
+  SQWConnInfo     ctrlConnInfo;
+  SQWConnInfo     dataConnInfo;
+
   int8_t          events[QW_EVENT_MAX];
   
   qTaskInfo_t     taskHandle;
diff --git a/source/libs/qworker/src/qworker.c b/source/libs/qworker/src/qworker.c
index 42d10a2361..726d0ebf79 100644
--- a/source/libs/qworker/src/qworker.c
+++ b/source/libs/qworker/src/qworker.c
@@ -432,8 +432,10 @@ int32_t qwKillTaskHandle(QW_FPARAMS_DEF, SQWTaskCtx *ctx) {
 
 
 void qwFreeTask(QW_FPARAMS_DEF, SQWTaskCtx *ctx) {
-  tmsgReleaseHandle(ctx->connInfo.handle, TAOS_CONN_SERVER);
-  ctx->connInfo.handle = NULL;
+  tmsgReleaseHandle(ctx->ctrlConnInfo.handle, TAOS_CONN_SERVER);
+  ctx->ctrlConnInfo.handle = NULL;
+
+  // NO need to release dataConnInfo
 
   qwFreeTaskHandle(QW_FPARAMS(), &ctx->taskHandle);
   
@@ -537,6 +539,26 @@ int32_t qwDropTask(QW_FPARAMS_DEF) {
   return TSDB_CODE_SUCCESS;
 }
 
+
+int32_t qwHandleTaskComplete(QW_FPARAMS_DEF, SQWTaskCtx *ctx) {
+  qTaskInfo_t *taskHandle = &ctx->taskHandle; 
+
+  if (TASK_TYPE_TEMP == ctx->taskType) {
+    if (ctx->explain) {
+      SExplainExecInfo *execInfo = NULL;
+      int32_t resNum = 0;
+      QW_ERR_RET(qGetExplainExecInfo(ctx->taskHandle, &resNum, &execInfo));
+
+      QW_ERR_RET(qwBuildAndSendExplainRsp(&ctx->ctrlConnInfo, &rsp));
+    }
+    
+    qwFreeTaskHandle(QW_FPARAMS(), taskHandle);
+  }
+
+  return TSDB_CODE_SUCCESS;
+}
+
+
 int32_t qwExecTask(QW_FPARAMS_DEF, SQWTaskCtx *ctx, bool *queryEnd) {
   int32_t code = 0;
   bool  qcontinue = true;
@@ -562,10 +584,8 @@ int32_t qwExecTask(QW_FPARAMS_DEF, SQWTaskCtx *ctx, bool *queryEnd) {
       QW_TASK_DLOG("qExecTask end with empty res, useconds:%"PRIu64, useconds);
 
       dsEndPut(sinkHandle, useconds);
-      
-      if (TASK_TYPE_TEMP == ctx->taskType) {
-        qwFreeTaskHandle(QW_FPARAMS(), taskHandle);
-      }
+
+      QW_ERR_RET(qwHandleTaskComplete(QW_FPARAMS(), ctx));
 
       if (queryEnd) {
         *queryEnd = true;
@@ -658,19 +678,6 @@ int32_t qwGetResFromSink(QW_FPARAMS_DEF, SQWTaskCtx *ctx, int32_t *dataLen, void
   bool queryEnd = false;
   int32_t code = 0;
 
-  if (ctx->emptyRes) {
-    QW_TASK_DLOG_E("query end with empty result");
-    
-    qwUpdateTaskStatus(QW_FPARAMS(), JOB_TASK_STATUS_SUCCEED);
-    QW_ERR_RET(qwMallocFetchRsp(len, &rsp));      
-    
-    *rspMsg = rsp;
-    *dataLen = 0;
-    pOutput->queryEnd = true;
-    
-    return TSDB_CODE_SUCCESS;
-  }
-
   dsGetDataLength(ctx->sinkHandle, &len, &queryEnd);
 
   if (len < 0) {
@@ -760,12 +767,12 @@ int32_t qwHandlePrePhaseEvents(QW_FPARAMS_DEF, int8_t phase, SQWPhaseInput *inpu
       }
 
       if (QW_IS_EVENT_RECEIVED(ctx, QW_EVENT_DROP)) {
-        dropConnection = &ctx->connInfo;
+        dropConnection = &ctx->ctrlConnInfo;
         QW_ERR_JRET(qwDropTask(QW_FPARAMS()));
         dropConnection = NULL;
 
-        qwBuildAndSendDropRsp(&ctx->connInfo, code);
-        QW_TASK_DLOG("drop rsp send, handle:%p, code:%x - %s", ctx->connInfo.handle, code, tstrerror(code));
+        qwBuildAndSendDropRsp(&ctx->ctrlConnInfo, code);
+        QW_TASK_DLOG("drop rsp send, handle:%p, code:%x - %s", ctx->ctrlConnInfo.handle, code, tstrerror(code));
 
         QW_ERR_JRET(TSDB_CODE_QRY_TASK_DROPPED);
         break;
@@ -798,12 +805,12 @@ int32_t qwHandlePrePhaseEvents(QW_FPARAMS_DEF, int8_t phase, SQWPhaseInput *inpu
       }
 
       if (QW_IS_EVENT_RECEIVED(ctx, QW_EVENT_DROP)) {
-        dropConnection = &ctx->connInfo;
+        dropConnection = &ctx->ctrlConnInfo;
         QW_ERR_JRET(qwDropTask(QW_FPARAMS()));
         dropConnection = NULL;
 
-        qwBuildAndSendDropRsp(&ctx->connInfo, code);
-        QW_TASK_DLOG("drop rsp send, handle:%p, code:%x - %s", ctx->connInfo.handle, code, tstrerror(code));
+        qwBuildAndSendDropRsp(&ctx->ctrlConnInfo, code);
+        QW_TASK_DLOG("drop rsp send, handle:%p, code:%x - %s", ctx->ctrlConnInfo.handle, code, tstrerror(code));
 
         QW_ERR_JRET(TSDB_CODE_QRY_TASK_DROPPED);
       }
@@ -863,17 +870,13 @@ int32_t qwHandlePostPhaseEvents(QW_FPARAMS_DEF, int8_t phase, SQWPhaseInput *inp
   }
 
   if (QW_PHASE_POST_QUERY == phase) {
-    if (NULL == ctx->taskHandle && NULL == ctx->sinkHandle) {
-      ctx->emptyRes = true;
-    }
-
 #if 0    
     if (QW_IS_EVENT_RECEIVED(ctx, QW_EVENT_READY)) {
       readyConnection = &ctx->connInfo;
       QW_SET_EVENT_PROCESSED(ctx, QW_EVENT_READY);
     }
 #else
-    connInfo.handle = ctx->connInfo.handle;
+    connInfo.handle = ctx->ctrlConnInfo.handle;
     readyConnection = &connInfo;
     
     QW_SET_EVENT_PROCESSED(ctx, QW_EVENT_READY);
@@ -886,8 +889,8 @@ int32_t qwHandlePostPhaseEvents(QW_FPARAMS_DEF, int8_t phase, SQWPhaseInput *inp
       QW_ERR_JRET(TSDB_CODE_QRY_APP_ERROR);
     }
 
-    qwBuildAndSendDropRsp(&ctx->connInfo, code);
-    QW_TASK_DLOG("drop rsp send, handle:%p, code:%x - %s", ctx->connInfo.handle, code, tstrerror(code));
+    qwBuildAndSendDropRsp(&ctx->ctrlConnInfo, code);
+    QW_TASK_DLOG("drop rsp send, handle:%p, code:%x - %s", ctx->ctrlConnInfo.handle, code, tstrerror(code));
 
     QW_ERR_JRET(qwDropTask(QW_FPARAMS()));
     QW_ERR_JRET(TSDB_CODE_QRY_TASK_DROPPED);
@@ -931,7 +934,7 @@ _return:
   QW_RET(code);
 }
 
-int32_t qwProcessQuery(QW_FPARAMS_DEF, SQWMsg *qwMsg, int8_t taskType) {
+int32_t qwProcessQuery(QW_FPARAMS_DEF, SQWMsg *qwMsg, int8_t taskType, int8_t explain) {
   int32_t code = 0;
   bool queryRsped = false;
   struct SSubplan *plan = NULL;
@@ -947,9 +950,10 @@ int32_t qwProcessQuery(QW_FPARAMS_DEF, SQWMsg *qwMsg, int8_t taskType) {
   QW_ERR_JRET(qwGetTaskCtx(QW_FPARAMS(), &ctx));
   
   atomic_store_8(&ctx->taskType, taskType);
+  atomic_store_8(&ctx->explain, explain);
 
-  atomic_store_ptr(&ctx->connInfo.handle, qwMsg->connInfo.handle);
-  atomic_store_ptr(&ctx->connInfo.ahandle, qwMsg->connInfo.ahandle);
+  atomic_store_ptr(&ctx->ctrlConnInfo.handle, qwMsg->connInfo.handle);
+  atomic_store_ptr(&ctx->ctrlConnInfo.ahandle, qwMsg->connInfo.ahandle);
 
   QW_TASK_DLOGL("subplan json string, len:%d, %s", qwMsg->msgLen, qwMsg->msg);
 
@@ -1011,8 +1015,8 @@ int32_t qwProcessReady(QW_FPARAMS_DEF, SQWMsg *qwMsg) {
   }
   
   if (ctx->phase == QW_PHASE_PRE_QUERY) {
-    ctx->connInfo.handle == qwMsg->connInfo.handle;
-    ctx->connInfo.ahandle = qwMsg->connInfo.ahandle;
+    ctx->ctrlConnInfo.handle == qwMsg->connInfo.handle;
+    ctx->ctrlConnInfo.ahandle = qwMsg->connInfo.ahandle;
     QW_SET_EVENT_RECEIVED(ctx, QW_EVENT_READY);
     needRsp = false;
     QW_TASK_DLOG_E("ready msg will not rsp now");
@@ -1089,10 +1093,13 @@ int32_t qwProcessCQuery(QW_FPARAMS_DEF, SQWMsg *qwMsg) {
       
       if (rsp) {
         bool qComplete = (DS_BUF_EMPTY == sOutput.bufStatus && sOutput.queryEnd);
+        
         qwBuildFetchRsp(rsp, &sOutput, dataLen, qComplete);
-        atomic_store_8((int8_t*)&ctx->queryEnd, qComplete);
+        if (qComplete) {
+          atomic_store_8((int8_t*)&ctx->queryEnd, true);
+        }
 
-        qwMsg->connInfo = ctx->connInfo;
+        qwMsg->connInfo = ctx->dataConnInfo;
         QW_SET_EVENT_PROCESSED(ctx, QW_EVENT_FETCH);            
         
         qwBuildAndSendFetchRsp(&qwMsg->connInfo, rsp, dataLen, code);                
@@ -1113,7 +1120,7 @@ _return:
       qwFreeFetchRsp(rsp);
       rsp = NULL;
       
-      qwMsg->connInfo = ctx->connInfo;
+      qwMsg->connInfo = ctx->dataConnInfo;
       qwBuildAndSendFetchRsp(&qwMsg->connInfo, rsp, 0, code);
       QW_TASK_DLOG("fetch rsp send, handle:%p, code:%x - %s, dataLen:%d", qwMsg->connInfo.handle, code, tstrerror(code), 0);
     }
@@ -1151,14 +1158,17 @@ int32_t qwProcessFetch(QW_FPARAMS_DEF, SQWMsg *qwMsg) {
   QW_ERR_JRET(qwGetResFromSink(QW_FPARAMS(), ctx, &dataLen, &rsp, &sOutput));
 
   if (NULL == rsp) {
-    atomic_store_ptr(&ctx->connInfo.handle, qwMsg->connInfo.handle);
-    atomic_store_ptr(&ctx->connInfo.ahandle, qwMsg->connInfo.ahandle);
+    atomic_store_ptr(&ctx->dataConnInfo.handle, qwMsg->connInfo.handle);
+    atomic_store_ptr(&ctx->dataConnInfo.ahandle, qwMsg->connInfo.ahandle);
     
     QW_SET_EVENT_RECEIVED(ctx, QW_EVENT_FETCH);
   } else {
     bool qComplete = (DS_BUF_EMPTY == sOutput.bufStatus && sOutput.queryEnd);
+    
     qwBuildFetchRsp(rsp, &sOutput, dataLen, qComplete);
-    atomic_store_8((int8_t*)&ctx->queryEnd, qComplete);
+    if (qComplete) {
+      atomic_store_8((int8_t*)&ctx->queryEnd, true);
+    }
   }
 
   if ((!sOutput.queryEnd) && (DS_BUF_LOW == sOutput.bufStatus || DS_BUF_EMPTY == sOutput.bufStatus)) {    
@@ -1236,8 +1246,8 @@ int32_t qwProcessDrop(QW_FPARAMS_DEF, SQWMsg *qwMsg) {
   }
 
   if (!rsped) {
-    ctx->connInfo.handle = qwMsg->connInfo.handle;
-    ctx->connInfo.ahandle = qwMsg->connInfo.ahandle;
+    ctx->ctrlConnInfo.handle = qwMsg->connInfo.handle;
+    ctx->ctrlConnInfo.ahandle = qwMsg->connInfo.ahandle;
     
     QW_SET_EVENT_RECEIVED(ctx, QW_EVENT_DROP);
   }
diff --git a/source/libs/qworker/src/qworkerMsg.c b/source/libs/qworker/src/qworkerMsg.c
index 80ae013653..c9779f9252 100644
--- a/source/libs/qworker/src/qworkerMsg.c
+++ b/source/libs/qworker/src/qworkerMsg.c
@@ -327,7 +327,7 @@ int32_t qWorkerProcessQueryMsg(void *node, void *qWorkerMgmt, SRpcMsg *pMsg) {
   QW_SCH_TASK_DLOG("processQuery start, node:%p, handle:%p, sql:%s", node, pMsg->handle, sql);
   taosMemoryFreeClear(sql);
 
-  QW_ERR_RET(qwProcessQuery(QW_FPARAMS(), &qwMsg, msg->taskType));
+  QW_ERR_RET(qwProcessQuery(QW_FPARAMS(), &qwMsg, msg->taskType, msg->explain));
 
   QW_SCH_TASK_DLOG("processQuery end, node:%p", node);
 
diff --git a/source/libs/scheduler/inc/schedulerInt.h b/source/libs/scheduler/inc/schedulerInt.h
index 22bd039219..62a96b6438 100644
--- a/source/libs/scheduler/inc/schedulerInt.h
+++ b/source/libs/scheduler/inc/schedulerInt.h
@@ -26,6 +26,7 @@ extern "C" {
 #include "scheduler.h"
 #include "thash.h"
 #include "trpc.h"
+#include "command.h"
 
 #define SCHEDULE_DEFAULT_MAX_JOB_NUM 1000
 #define SCHEDULE_DEFAULT_MAX_TASK_NUM 1000
@@ -165,6 +166,7 @@ typedef struct SSchJob {
   SHashObj        *succTasks; // succeed tasks, key:taskid, value:SQueryTask*
   SHashObj        *failTasks; // failed tasks, key:taskid, value:SQueryTask*
 
+  SExplainCtx     *explainCtx;
   int8_t           status;  
   SQueryNodeAddr   resNode;
   tsem_t           rspSem;
@@ -211,6 +213,7 @@ extern SSchedulerMgmt schMgmt;
 #define SCH_JOB_NEED_FETCH(_job) SCH_IS_QUERY_JOB(_job)
 #define SCH_IS_WAIT_ALL_JOB(_job) (!SCH_IS_QUERY_JOB(_job))
 #define SCH_IS_NEED_DROP_JOB(_job) (SCH_IS_QUERY_JOB(_job))
+#define SCH_IS_EXPLAIN_JOB(_job) (EXPLAIN_MODE_ANALYZE == (_job)->attr.explainMode)
 
 #define SCH_IS_LEVEL_UNFINISHED(_level) ((_level)->taskLaunchedNum < (_level)->taskNum)
 #define SCH_GET_CUR_EP(_addr) (&(_addr)->epSet.eps[(_addr)->epSet.inUse])
@@ -251,6 +254,8 @@ int32_t schFetchFromRemote(SSchJob *pJob);
 int32_t schProcessOnTaskFailure(SSchJob *pJob, SSchTask *pTask, int32_t errCode);
 int32_t schBuildAndSendHbMsg(SQueryNodeEpId *nodeEpId);
 int32_t schCloneSMsgSendInfo(void *src, void **dst);
+int32_t schValidateAndBuildJob(SQueryPlan *pDag, SSchJob *pJob);
+void schFreeJobImpl(void *job);
 
 
 #ifdef __cplusplus
diff --git a/source/libs/scheduler/src/scheduler.c b/source/libs/scheduler/src/scheduler.c
index 9c5019aedc..658d924f38 100644
--- a/source/libs/scheduler/src/scheduler.c
+++ b/source/libs/scheduler/src/scheduler.c
@@ -67,6 +67,81 @@ int32_t schInitTask(SSchJob *pJob, SSchTask *pTask, SSubplan *pPlan, SSchLevel *
   return TSDB_CODE_SUCCESS;
 }
 
+int32_t schInitJob(SSchJob **pSchJob, SQueryPlan *pDag, void *transport, SArray *pNodeList, const char *sql,
+                              int64_t startTs, bool syncSchedule) {
+  int32_t code = 0;
+  SSchJob *pJob = taosMemoryCalloc(1, sizeof(SSchJob));
+  if (NULL == pJob) {
+    qError("QID:%" PRIx64 " calloc %d failed", pDag->queryId, (int32_t)sizeof(SSchJob));
+    SCH_ERR_RET(TSDB_CODE_QRY_OUT_OF_MEMORY);
+  }
+
+  pJob->attr.explainMode = pDag->explainInfo.mode;
+  pJob->attr.syncSchedule = syncSchedule;
+  pJob->transport = transport;
+  pJob->sql = sql;
+
+  if (pNodeList != NULL) {
+    pJob->nodeList = taosArrayDup(pNodeList);
+  }
+
+  SCH_ERR_JRET(schValidateAndBuildJob(pDag, pJob));
+
+  if (SCH_IS_EXPLAIN_JOB(pJob)) {
+    SCH_ERR_JRET(qExecExplainBegin(pDag, &pJob->explainCtx, startTs));
+  }
+
+  pJob->execTasks =
+      taosHashInit(pDag->numOfSubplans, taosGetDefaultHashFunction(TSDB_DATA_TYPE_UBIGINT), false, HASH_ENTRY_LOCK);
+  if (NULL == pJob->execTasks) {
+    SCH_JOB_ELOG("taosHashInit %d execTasks failed", pDag->numOfSubplans);
+    SCH_ERR_JRET(TSDB_CODE_QRY_OUT_OF_MEMORY);
+  }
+
+  pJob->succTasks =
+      taosHashInit(pDag->numOfSubplans, taosGetDefaultHashFunction(TSDB_DATA_TYPE_UBIGINT), false, HASH_ENTRY_LOCK);
+  if (NULL == pJob->succTasks) {
+    SCH_JOB_ELOG("taosHashInit %d succTasks failed", pDag->numOfSubplans);
+    SCH_ERR_JRET(TSDB_CODE_QRY_OUT_OF_MEMORY);
+  }
+
+  pJob->failTasks =
+      taosHashInit(pDag->numOfSubplans, taosGetDefaultHashFunction(TSDB_DATA_TYPE_UBIGINT), false, HASH_ENTRY_LOCK);
+  if (NULL == pJob->failTasks) {
+    SCH_JOB_ELOG("taosHashInit %d failTasks failed", pDag->numOfSubplans);
+    SCH_ERR_JRET(TSDB_CODE_QRY_OUT_OF_MEMORY);
+  }
+
+  tsem_init(&pJob->rspSem, 0, 0);
+
+  int64_t refId = taosAddRef(schMgmt.jobRef, pJob);
+  if (refId < 0) {
+    SCH_JOB_ELOG("taosAddRef job failed, error:%s", tstrerror(terrno));
+    SCH_ERR_JRET(terrno);
+  }
+
+  if (NULL == schAcquireJob(refId)) {
+    SCH_JOB_ELOG("schAcquireJob job failed, refId:%" PRIx64, refId);
+    SCH_RET(TSDB_CODE_SCH_STATUS_ERROR);
+  }
+
+  pJob->refId = refId;
+
+  SCH_JOB_DLOG("job refId:%" PRIx64, pJob->refId);
+
+  pJob->status = JOB_TASK_STATUS_NOT_START;
+
+  *pSchJob = pJob;
+
+  return TSDB_CODE_SUCCESS;
+
+_return:
+
+  schFreeJobImpl(pJob);
+  SCH_RET(code);
+}
+
+
 void schFreeRpcCtx(SRpcCtx *pCtx) {
   if (NULL == pCtx) {
     return;
@@ -1050,6 +1125,40 @@ int32_t schHandleResponseMsg(SSchJob *pJob, SSchTask *pTask, int32_t msgType, ch
 
       break;
     }
+    case TDMT_VND_EXPLAIN_RSP: {
+      SExplainRsp *taskRsp = (SExplainRsp *)msg;
+
+      SCH_ERR_JRET(rspCode);
+      if (NULL == msg) {
+        SCH_ERR_JRET(TSDB_CODE_QRY_INVALID_INPUT);
+      }
+
+      if (!SCH_IS_EXPLAIN_JOB(pJob)) {
+        SCH_TASK_ELOG("invalid msg received for none explain query, msg type:%s", TMSG_INFO(msgType));
+        SCH_ERR_JRET(TSDB_CODE_QRY_INVALID_INPUT);
+      }
+
+      if (pJob->resData) {
+        SCH_TASK_ELOG("explain result is already generated, res:%p", pJob->resData);
+        taosMemoryFreeClear(taskRsp);
+        SCH_ERR_JRET(TSDB_CODE_SCH_STATUS_ERROR);
+      }
+
+      SRetrieveTableRsp *pRsp = NULL;
+      SCH_ERR_JRET(qExplainUpdateExecInfo(pJob->explainCtx, taskRsp, pTask->plan->id.groupId, &pRsp));
+
+      if (pRsp) {
+        atomic_store_ptr(&pJob->resData, pRsp);
+        atomic_store_32(&pJob->resNumOfRows, htonl(pRsp->numOfRows));
+
+        SCH_SET_TASK_STATUS(pTask, JOB_TASK_STATUS_SUCCEED);
+
+        SCH_TASK_DLOG("got explain rsp, rows:%d, complete:%d", htonl(pRsp->numOfRows), pRsp->completed);
+
+        schProcessOnDataFetched(pJob);
+      }
+      break;
+    }
     case TDMT_VND_FETCH_RSP: {
       SRetrieveTableRsp *rsp = (SRetrieveTableRsp *)msg;
 
@@ -1058,6 +1167,17 @@ int32_t schHandleResponseMsg(SSchJob *pJob, SSchTask *pTask, int32_t msgType, ch
         SCH_ERR_JRET(TSDB_CODE_QRY_INVALID_INPUT);
       }
 
+      if (SCH_IS_EXPLAIN_JOB(pJob)) {
+        if (rsp->completed) {
+          SCH_ERR_JRET(qExecExplainEnd(pJob->explainCtx));
+          return TSDB_CODE_SUCCESS;
+        }
+
+        SCH_ERR_JRET(schFetchFromRemote(pJob));
+
+        return TSDB_CODE_SUCCESS;
+      }
+
       if (pJob->resData) {
         SCH_TASK_ELOG("got fetch rsp while res already exists, res:%p", pJob->resData);
         taosMemoryFreeClear(rsp);
@@ -1767,6 +1887,7 @@ int32_t schBuildAndSendMsg(SSchJob *pJob, SSchTask *pTask, SQueryNodeAddr *addr,
       pMsg->taskId = htobe64(pTask->taskId);
       pMsg->refId = htobe64(pJob->refId);
       pMsg->taskType = TASK_TYPE_TEMP;
+      pMsg->explain = SCH_IS_EXPLAIN_JOB(pJob);
       pMsg->phyLen = htonl(pTask->msgLen);
       pMsg->sqlLen = htonl(len);
 
@@ -2083,6 +2204,8 @@ void schFreeJobImpl(void *job) {
   taosArrayDestroy(pJob->levels);
   taosArrayDestroy(pJob->nodeList);
 
+  qExplainFreeCtx(pJob->explainCtx);
+
   taosMemoryFreeClear(pJob->resData);
   taosMemoryFreeClear(pJob);
 
@@ -2090,70 +2213,17 @@ void schFreeJobImpl(void *job) {
 }
 
 static int32_t schExecJobImpl(void *transport, SArray *pNodeList, SQueryPlan *pDag, int64_t *job, const char *sql,
-                              bool syncSchedule) {
+                              int64_t startTs, bool syncSchedule) {
   qDebug("QID:0x%" PRIx64 " job started", pDag->queryId);
 
-  if (pNodeList == NULL || (pNodeList && taosArrayGetSize(pNodeList) <= 0)) {
+  if (pNodeList == NULL || taosArrayGetSize(pNodeList) <= 0) {
     qDebug("QID:0x%" PRIx64 " input exec nodeList is empty", pDag->queryId);
   }
 
   int32_t  code = 0;
-  SSchJob *pJob = taosMemoryCalloc(1, sizeof(SSchJob));
-  if (NULL == pJob) {
-    qError("QID:%" PRIx64 " calloc %d failed", pDag->queryId, (int32_t)sizeof(SSchJob));
-    SCH_ERR_RET(TSDB_CODE_QRY_OUT_OF_MEMORY);
-  }
+  SSchJob *pJob = NULL;
+  SCH_ERR_JRET(schInitJob(&pJob, pDag, transport, pNodeList, sql, startTs, syncSchedule));
 
-  pJob->attr.explainMode = pDag->explainInfo.mode;
-  pJob->attr.syncSchedule = syncSchedule;
-  pJob->transport = transport;
-  pJob->sql = sql;
-
-  if (pNodeList != NULL) {
-    pJob->nodeList = taosArrayDup(pNodeList);
-  }
-
-  SCH_ERR_JRET(schValidateAndBuildJob(pDag, pJob));
-
-  pJob->execTasks =
-      taosHashInit(pDag->numOfSubplans, taosGetDefaultHashFunction(TSDB_DATA_TYPE_UBIGINT), false, HASH_ENTRY_LOCK);
-  if (NULL == pJob->execTasks) {
-    SCH_JOB_ELOG("taosHashInit %d execTasks failed", pDag->numOfSubplans);
-    SCH_ERR_JRET(TSDB_CODE_QRY_OUT_OF_MEMORY);
-  }
-
-  pJob->succTasks =
-      taosHashInit(pDag->numOfSubplans, taosGetDefaultHashFunction(TSDB_DATA_TYPE_UBIGINT), false, HASH_ENTRY_LOCK);
-  if (NULL == pJob->succTasks) {
-    SCH_JOB_ELOG("taosHashInit %d succTasks failed", pDag->numOfSubplans);
-    SCH_ERR_JRET(TSDB_CODE_QRY_OUT_OF_MEMORY);
-  }
-
-  pJob->failTasks =
-      taosHashInit(pDag->numOfSubplans, taosGetDefaultHashFunction(TSDB_DATA_TYPE_UBIGINT), false, HASH_ENTRY_LOCK);
-  if (NULL == pJob->failTasks) {
-    SCH_JOB_ELOG("taosHashInit %d failTasks failed", pDag->numOfSubplans);
-    SCH_ERR_JRET(TSDB_CODE_QRY_OUT_OF_MEMORY);
-  }
-
-  tsem_init(&pJob->rspSem, 0, 0);
-
-  int64_t refId = taosAddRef(schMgmt.jobRef, pJob);
-  if (refId < 0) {
-    SCH_JOB_ELOG("taosAddRef job failed, error:%s", tstrerror(terrno));
-    SCH_ERR_JRET(terrno);
-  }
-
-  if (NULL == schAcquireJob(refId)) {
-    SCH_JOB_ELOG("schAcquireJob job failed, refId:%" PRIx64, refId);
-    SCH_RET(TSDB_CODE_SCH_STATUS_ERROR);
-  }
-
-  pJob->refId = refId;
-
-  SCH_JOB_DLOG("job refId:%" PRIx64, pJob->refId);
-
-  pJob->status = JOB_TASK_STATUS_NOT_START;
   SCH_ERR_JRET(schLaunchJob(pJob));
 
   *job = pJob->refId;
@@ -2266,7 +2336,7 @@ int32_t schedulerInit(SSchedulerCfg *cfg) {
 }
 
 int32_t schedulerExecJob(void *transport, SArray *nodeList, SQueryPlan *pDag, int64_t *pJob, const char *sql,
-                         SQueryResult *pRes) {
+                         int64_t startTs, SQueryResult *pRes) {
   if (NULL == transport || NULL == pDag || NULL == pDag->pSubplans || NULL == pJob || NULL == pRes) {
     SCH_ERR_RET(TSDB_CODE_QRY_INVALID_INPUT);
   }
@@ -2274,7 +2344,7 @@ int32_t schedulerExecJob(void *transport, SArray *nodeList, SQueryPlan *pDag, in
   if (EXPLAIN_MODE_STATIC == pDag->explainInfo.mode) {
     SCH_ERR_RET(schExecStaticExplain(transport, nodeList, pDag, pJob, sql, true));
   } else {
-    SCH_ERR_RET(schExecJobImpl(transport, nodeList, pDag, pJob, sql, true));
+    SCH_ERR_RET(schExecJobImpl(transport, nodeList, pDag, pJob, sql, startTs, true));
   }
 
   SSchJob *job = schAcquireJob(*pJob);
@@ -2292,7 +2362,11 @@ int32_t schedulerAsyncExecJob(void *transport, SArray *pNodeList, SQueryPlan *pD
     SCH_ERR_RET(TSDB_CODE_QRY_INVALID_INPUT);
   }
 
-  SCH_ERR_RET(schExecJobImpl(transport, pNodeList, pDag, pJob, sql, false));
+  if (EXPLAIN_MODE_STATIC == pDag->explainInfo.mode) {
+    SCH_ERR_RET(schExecStaticExplain(transport, pNodeList, pDag, pJob, sql, false));
+  } else {
+    SCH_ERR_RET(schExecJobImpl(transport, pNodeList, pDag, pJob, sql, 0, false));
+  }
 
   return TSDB_CODE_SUCCESS;
 }
diff --git a/source/libs/scheduler/test/schedulerTests.cpp b/source/libs/scheduler/test/schedulerTests.cpp
index cf04b06579..5d9322a575 100644
--- a/source/libs/scheduler/test/schedulerTests.cpp
+++ b/source/libs/scheduler/test/schedulerTests.cpp
@@ -951,7 +951,7 @@ TEST(insertTest, normalCase) {
   taosThreadCreate(&(thread1), &thattr, schtSendRsp, &insertJobRefId);
 
   SQueryResult res = {0};
-  code = schedulerExecJob(mockPointer, qnodeList, &dag, &insertJobRefId, "insert into tb values(now,1)", &res);
+  code = schedulerExecJob(mockPointer, qnodeList, &dag, &insertJobRefId, "insert into tb values(now,1)", 0, &res);
   ASSERT_EQ(code, 0);
   ASSERT_EQ(res.numOfRows, 20);