diff --git a/include/os/osMemory.h b/include/os/osMemory.h
index c35fd782fbb1d5a4b585ef735d179a09ce0d691e..44a97bf05517241cf32d48fcfe940dcbb216859a 100644
--- a/include/os/osMemory.h
+++ b/include/os/osMemory.h
@@ -29,11 +29,10 @@ extern "C" {
 #define calloc  CALLOC_FUNC_TAOS_FORBID
 #define realloc REALLOC_FUNC_TAOS_FORBID
 #define free    FREE_FUNC_TAOS_FORBID
-#ifdef  strdup
-#undef  strdup
+#ifdef strdup
+#undef strdup
 #define strdup  STRDUP_FUNC_TAOS_FORBID
 #endif
-
 #endif // ifndef ALLOW_FORBID_FUNC
 #endif // if !defined(WINDOWS)
 
diff --git a/source/dnode/mnode/impl/src/mndConsumer.c b/source/dnode/mnode/impl/src/mndConsumer.c
index 6621b6a3f9e0efe1536172607441c11e34eeacd6..280f3b0eccb4c7d8b8b3929c24d470a05bbff399 100644
--- a/source/dnode/mnode/impl/src/mndConsumer.c
+++ b/source/dnode/mnode/impl/src/mndConsumer.c
@@ -15,17 +15,11 @@
 
 #define _DEFAULT_SOURCE
 #include "mndConsumer.h"
-#include "mndDb.h"
-#include "mndDnode.h"
-#include "mndMnode.h"
 #include "mndPrivilege.h"
 #include "mndShow.h"
-#include "mndStb.h"
 #include "mndSubscribe.h"
 #include "mndTopic.h"
 #include "mndTrans.h"
-#include "mndUser.h"
-#include "mndVgroup.h"
 #include "tcompare.h"
 #include "tname.h"
 
@@ -209,6 +203,7 @@ static int32_t mndProcessConsumerClearMsg(SRpcMsg *pMsg) {
   taosMemoryFree(pConsumerNew);
   mndTransDrop(pTrans);
   return 0;
+
 FAIL:
   tDeleteSMqConsumerObj(pConsumerNew);
   taosMemoryFree(pConsumerNew);
@@ -580,6 +575,10 @@ static int32_t validateTopics(const SArray* pTopicList, SMnode* pMnode, const ch
   return 0;
 }
 
+static void* topicNameDup(void* p){
+  return taosStrdup((char*) p);
+}
+
 int32_t mndProcessSubscribeReq(SRpcMsg *pMsg) {
   SMnode *pMnode = pMsg->info.node;
   char   *msgStr = pMsg->pCont;
@@ -616,16 +615,17 @@ int32_t mndProcessSubscribeReq(SRpcMsg *pMsg) {
 
     pConsumerNew = tNewSMqConsumerObj(consumerId, cgroup);
     tstrncpy(pConsumerNew->clientId, subscribe.clientId, 256);
+
+    // set the update type
     pConsumerNew->updateType = CONSUMER_UPDATE__MODIFY;
+    taosArrayDestroy(pConsumerNew->assignedTopics);
+    pConsumerNew->assignedTopics = taosArrayDup(pTopicList, topicNameDup);
+
+    // all subscribed topics should re-balance.
     taosArrayDestroy(pConsumerNew->rebNewTopics);
-    pConsumerNew->rebNewTopics = pTopicList;  // all subscribe topics should re-balance.
+    pConsumerNew->rebNewTopics = pTopicList;
     subscribe.topicNames = NULL;
 
-    for (int32_t i = 0; i < newTopicNum; i++) {
-      char *newTopicCopy = taosStrdup(taosArrayGetP(pTopicList, i));
-      taosArrayPush(pConsumerNew->assignedTopics, &newTopicCopy);
-    }
-
     if (mndSetConsumerCommitLogs(pMnode, pTrans, pConsumerNew) != 0) goto _over;
     if (mndTransPrepare(pMnode, pTrans) != 0) goto _over;
 
@@ -646,17 +646,12 @@ int32_t mndProcessSubscribeReq(SRpcMsg *pMsg) {
       goto _over;
     }
 
+    // set the update type
     pConsumerNew->updateType = CONSUMER_UPDATE__MODIFY;
+    taosArrayDestroy(pConsumerNew->assignedTopics);
+    pConsumerNew->assignedTopics = taosArrayDup(pTopicList, topicNameDup);
 
-    for (int32_t i = 0; i < newTopicNum; i++) {
-      char *newTopicCopy = taosStrdup(taosArrayGetP(pTopicList, i));
-      taosArrayPush(pConsumerNew->assignedTopics, &newTopicCopy);
-    }
-
-    int32_t oldTopicNum = 0;
-    if (pExistedConsumer->currentTopics) {
-      oldTopicNum = taosArrayGetSize(pExistedConsumer->currentTopics);
-    }
+    int32_t oldTopicNum = (pExistedConsumer->currentTopics)? taosArrayGetSize(pExistedConsumer->currentTopics):0;
 
     int32_t i = 0, j = 0;
     while (i < oldTopicNum || j < newTopicNum) {
@@ -692,11 +687,8 @@ int32_t mndProcessSubscribeReq(SRpcMsg *pMsg) {
       }
     }
 
-    if (pExistedConsumer && taosArrayGetSize(pConsumerNew->rebNewTopics) == 0 &&
-        taosArrayGetSize(pConsumerNew->rebRemovedTopics) == 0) {
-      /*if (taosArrayGetSize(pConsumerNew->assignedTopics) == 0) {*/
-      /*pConsumerNew->updateType = */
-      /*}*/
+    // no topics need to be rebalanced
+    if (taosArrayGetSize(pConsumerNew->rebNewTopics) == 0 && taosArrayGetSize(pConsumerNew->rebRemovedTopics) == 0) {
       goto _over;
     }
 
@@ -718,8 +710,9 @@ _over:
     tDeleteSMqConsumerObj(pConsumerNew);
     taosMemoryFree(pConsumerNew);
   }
+
   // TODO: replace with destroy subscribe msg
-  if (subscribe.topicNames) taosArrayDestroyP(subscribe.topicNames, (FDelete)taosMemoryFree);
+  taosArrayDestroyP(subscribe.topicNames, (FDelete)taosMemoryFree);
   return code;
 }
 
@@ -750,12 +743,12 @@ SSdbRaw *mndConsumerActionEncode(SMqConsumerObj *pConsumer) {
 CM_ENCODE_OVER:
   taosMemoryFreeClear(buf);
   if (terrno != 0) {
-    mError("consumer:%" PRId64 ", failed to encode to raw:%p since %s", pConsumer->consumerId, pRaw, terrstr());
+    mError("consumer:0x%" PRIx64 " failed to encode to raw:%p since %s", pConsumer->consumerId, pRaw, terrstr());
     sdbFreeRaw(pRaw);
     return NULL;
   }
 
-  mTrace("consumer:%" PRId64 ", encode to raw:%p, row:%p", pConsumer->consumerId, pRaw, pConsumer);
+  mTrace("consumer:0x%" PRIx64 ", encode to raw:%p, row:%p", pConsumer->consumerId, pRaw, pConsumer);
   return pRaw;
 }
 
@@ -823,8 +816,8 @@ static int32_t mndConsumerActionInsert(SSdb *pSdb, SMqConsumerObj *pConsumer) {
 }
 
 static int32_t mndConsumerActionDelete(SSdb *pSdb, SMqConsumerObj *pConsumer) {
-  mDebug("consumer:0x%" PRIx64 " perform delete action, status:%s", pConsumer->consumerId,
-         mndConsumerStatusName(pConsumer->status));
+  mDebug("consumer:0x%" PRIx64 " perform delete action, status:(%d)%s", pConsumer->consumerId,
+         pConsumer->status, mndConsumerStatusName(pConsumer->status));
   tDeleteSMqConsumerObj(pConsumer);
   return 0;
 }
@@ -1075,22 +1068,23 @@ static int32_t mndRetrieveConsumer(SRpcMsg *pReq, SShowObj *pShow, SSDataBlock *
 
       // consumer group
       char cgroup[TSDB_CGROUP_LEN + VARSTR_HEADER_SIZE] = {0};
-      tstrncpy(varDataVal(cgroup), pConsumer->cgroup, TSDB_CGROUP_LEN);
-      varDataSetLen(cgroup, strlen(varDataVal(cgroup)));
+      STR_TO_VARSTR(cgroup, pConsumer->cgroup);
+
       pColInfo = taosArrayGet(pBlock->pDataBlock, cols++);
       colDataSetVal(pColInfo, numOfRows, (const char *)cgroup, false);
 
       // client id
       char clientId[256 + VARSTR_HEADER_SIZE] = {0};
-      tstrncpy(varDataVal(clientId), pConsumer->clientId, 256);
-      varDataSetLen(clientId, strlen(varDataVal(clientId)));
+      STR_TO_VARSTR(clientId, pConsumer->clientId);
+
       pColInfo = taosArrayGet(pBlock->pDataBlock, cols++);
       colDataSetVal(pColInfo, numOfRows, (const char *)clientId, false);
 
       // status
       char status[20 + VARSTR_HEADER_SIZE] = {0};
-      tstrncpy(varDataVal(status), mndConsumerStatusName(pConsumer->status), 20);
-      varDataSetLen(status, strlen(varDataVal(status)));
+      const char* pStatusName = mndConsumerStatusName(pConsumer->status);
+      STR_TO_VARSTR(status, pStatusName);
+
       pColInfo = taosArrayGet(pBlock->pDataBlock, cols++);
       colDataSetVal(pColInfo, numOfRows, (const char *)status, false);
 
@@ -1123,8 +1117,11 @@ static int32_t mndRetrieveConsumer(SRpcMsg *pReq, SShowObj *pShow, SSDataBlock *
 
       numOfRows++;
     }
+
     taosRUnLockLatch(&pConsumer->lock);
     sdbRelease(pSdb, pConsumer);
+
+    pBlock->info.rows = numOfRows;
   }
 
   pShow->numOfRows += numOfRows;
diff --git a/source/dnode/mnode/impl/src/mndSubscribe.c b/source/dnode/mnode/impl/src/mndSubscribe.c
index 8d8fd1b9b5ef39273f697a3f17dcef2365b13529..8544994c3ec2c0db0b8a559f15b32dc93ee7f16e 100644
--- a/source/dnode/mnode/impl/src/mndSubscribe.c
+++ b/source/dnode/mnode/impl/src/mndSubscribe.c
@@ -16,15 +16,10 @@
 #define _DEFAULT_SOURCE
 #include "mndSubscribe.h"
 #include "mndConsumer.h"
-#include "mndDb.h"
-#include "mndDnode.h"
-#include "mndMnode.h"
 #include "mndScheduler.h"
 #include "mndShow.h"
-#include "mndStb.h"
 #include "mndTopic.h"
 #include "mndTrans.h"
-#include "mndUser.h"
 #include "mndVgroup.h"
 #include "tcompare.h"
 #include "tname.h"
@@ -1041,7 +1036,6 @@ int32_t mndRetrieveSubscribe(SRpcMsg *pReq, SShowObj *pShow, SSDataBlock *pBlock
     }
 
     // do not show for cleared subscription
-#if 1
     int32_t sz = taosArrayGetSize(pSub->unassignedVgs);
     for (int32_t i = 0; i < sz; i++) {
       SMqVgEp *pVgEp = taosArrayGetP(pSub->unassignedVgs, i);
@@ -1087,8 +1081,6 @@ int32_t mndRetrieveSubscribe(SRpcMsg *pReq, SShowObj *pShow, SSDataBlock *pBlock
       numOfRows++;
     }
 
-#endif
-
     pBlock->info.rows = numOfRows;
 
     taosRUnLockLatch(&pSub->lock);
diff --git a/source/dnode/vnode/src/tq/tq.c b/source/dnode/vnode/src/tq/tq.c
index c9bbb30380a23be201eea3969b0b09beb580b0ed..c465617975858c6a91bce96c009126e0b1c1580a 100644
--- a/source/dnode/vnode/src/tq/tq.c
+++ b/source/dnode/vnode/src/tq/tq.c
@@ -217,7 +217,7 @@ int32_t tqPushDataRsp(STQ* pTq, STqPushEntry* pPushEntry) {
   char buf2[80] = {0};
   tFormatOffset(buf1, tListLen(buf1), &pRsp->reqOffset);
   tFormatOffset(buf2, tListLen(buf2), &pRsp->rspOffset);
-  tqDebug("vgId:%d, from consumer:0x%" PRIx64 " (epoch %d) push rsp, block num: %d, reqOffset:%s, rspOffset:%s",
+  tqDebug("vgId:%d, from consumer:0x%" PRIx64 " (epoch %d) push rsp, block num: %d, req:%s, rsp:%s",
           TD_VID(pTq->pVnode), pRsp->head.consumerId, pRsp->head.epoch, pRsp->blockNum, buf1, buf2);
 
   return 0;
@@ -275,7 +275,7 @@ int32_t tqSendDataRsp(STQ* pTq, const SRpcMsg* pMsg, const SMqPollReq* pReq, con
   char buf2[80] = {0};
   tFormatOffset(buf1, 80, &pRsp->reqOffset);
   tFormatOffset(buf2, 80, &pRsp->rspOffset);
-  tqDebug("vgId:%d consumer:0x%" PRIx64 " (epoch %d), block num:%d, reqOffset:%s, rspOffset:%s",
+  tqDebug("vgId:%d consumer:0x%" PRIx64 " (epoch %d), block num:%d, req:%s, rsp:%s",
           TD_VID(pTq->pVnode), pReq->consumerId, pReq->epoch, pRsp->blockNum, buf1, buf2);
 
   return 0;
@@ -604,7 +604,7 @@ int32_t tqProcessPollReq(STQ* pTq, SRpcMsg* pMsg) {
       code = -1;
     }
 
-    tqDebug("tmq poll: consumer:0x%" PRIx64 ", subkey %s, vgId:%d, rsp data block:%d, offset type:%d, uid/version:%" PRId64 ", ts:%" PRId64 "",
+    tqDebug("tmq poll: consumer:0x%" PRIx64 ", subkey %s, vgId:%d, rsp block:%d, offset type:%d, uid/version:%" PRId64 ", ts:%" PRId64 "",
             consumerId, pHandle->subKey, TD_VID(pTq->pVnode), dataRsp.blockNum, dataRsp.rspOffset.type,
             dataRsp.rspOffset.uid, dataRsp.rspOffset.ts);
 
diff --git a/source/dnode/vnode/src/tq/tqExec.c b/source/dnode/vnode/src/tq/tqExec.c
index e92da7668ad85c8d42d8d238222d830cad54fce3..563822864115a671867baac72451d48ecb2418e5 100644
--- a/source/dnode/vnode/src/tq/tqExec.c
+++ b/source/dnode/vnode/src/tq/tqExec.c
@@ -113,9 +113,7 @@ int32_t tqScanData(STQ* pTq, const STqHandle* pHandle, SMqDataRsp* pRsp, STqOffs
     return -1;
   }
 
-  ASSERT(pRsp->withTbName == false);
-  ASSERT(pRsp->withSchema == false);
-
+  ASSERT(!(pRsp->withTbName || pRsp->withSchema));
   return 0;
 }
 
diff --git a/source/dnode/vnode/src/tq/tqMeta.c b/source/dnode/vnode/src/tq/tqMeta.c
index 12fd15c63a5088a8da2ceb4de9b57f653976bc8a..a85e6e0a707d63e9b5dc76231cd5f8930f4f9616 100644
--- a/source/dnode/vnode/src/tq/tqMeta.c
+++ b/source/dnode/vnode/src/tq/tqMeta.c
@@ -197,7 +197,7 @@ int32_t tqMetaSaveHandle(STQ* pTq, const char* key, const STqHandle* pHandle) {
     return -1;
   }
 
-  tqDebug("tq save %s(%d) handle consumer:0x%" PRIx64 "epoch:%d  vgId:%d", pHandle->subKey,
+  tqDebug("tq save %s(%d) handle consumer:0x%" PRIx64 " epoch:%d vgId:%d", pHandle->subKey,
           (int32_t)strlen(pHandle->subKey), pHandle->consumerId, pHandle->epoch, TD_VID(pTq->pVnode));
 
   void* buf = taosMemoryCalloc(1, vlen);
diff --git a/source/dnode/vnode/src/tq/tqPush.c b/source/dnode/vnode/src/tq/tqPush.c
index e74726227794b2aab7072e81203e1747f2eb4ea7..5a25d7e89468b29e6c597c555d27afb259f09b63 100644
--- a/source/dnode/vnode/src/tq/tqPush.c
+++ b/source/dnode/vnode/src/tq/tqPush.c
@@ -193,7 +193,7 @@ int32_t tqPushMsgNew(STQ* pTq, void* msg, int32_t msgLen, tmsg_t msgType, int64_
     memset(&pHandle->pushHandle.rpcInfo, 0, sizeof(SRpcHandleInfo));
     taosWUnLockLatch(&pHandle->pushHandle.lock);
 
-    tqDebug("vgId:%d offset %" PRId64 " from consumer:%" PRId64 ", (epoch %d) send rsp, block num: %d, reqOffset:%" PRId64 ", rspOffset:%" PRId64,
+    tqDebug("vgId:%d offset %" PRId64 " from consumer:%" PRId64 ", (epoch %d) send rsp, block num: %d, req:%" PRId64 ", rsp:%" PRId64,
             TD_VID(pTq->pVnode), fetchOffset, pHandle->pushHandle.consumerId, pHandle->pushHandle.epoch, rsp.blockNum,
             rsp.reqOffset, rsp.rspOffset);
 
@@ -210,25 +210,30 @@ int tqPushMsg(STQ* pTq, void* msg, int32_t msgLen, tmsg_t msgType, int64_t ver)
   void*   pReq = POINTER_SHIFT(msg, sizeof(SSubmitReq2Msg));
   int32_t len = msgLen - sizeof(SSubmitReq2Msg);
 
-  tqDebug("vgId:%d tq push msg version:%" PRId64 " type: %s, p head %p, p body %p, len %d", pTq->pVnode->config.vgId, ver,
-          TMSG_INFO(msgType), msg, pReq, len);
-
   if (msgType == TDMT_VND_SUBMIT) {
     // lock push mgr to avoid potential msg lost
     taosWLockLatch(&pTq->pushLock);
-    if (taosHashGetSize(pTq->pPushMgr) != 0) {
 
-      tqDebug("vgId:%d, push handle num %d", pTq->pVnode->config.vgId, taosHashGetSize(pTq->pPushMgr));
+    int32_t numOfRegisteredPush = taosHashGetSize(pTq->pPushMgr);
+    if (numOfRegisteredPush > 0) {
+      tqDebug("vgId:%d tq push msg version:%" PRId64 " type:%s, head:%p, body:%p len:%d, numOfPushed consumers:%d",
+          pTq->pVnode->config.vgId, ver, TMSG_INFO(msgType), msg, pReq, len, numOfRegisteredPush);
+
       SArray* cachedKeys = taosArrayInit(0, sizeof(void*));
       SArray* cachedKeyLens = taosArrayInit(0, sizeof(size_t));
+
       void*   data = taosMemoryMalloc(len);
       if (data == NULL) {
         terrno = TSDB_CODE_OUT_OF_MEMORY;
         tqError("failed to copy data for stream since out of memory");
         taosArrayDestroyP(cachedKeys, (FDelete)taosMemoryFree);
         taosArrayDestroy(cachedKeyLens);
+
+        // unlock
+        taosWUnLockLatch(&pTq->pushLock);
         return -1;
       }
+
       memcpy(data, pReq, len);
 
       void* pIter = NULL;
@@ -262,7 +267,7 @@ int tqPushMsg(STQ* pTq, void* msg, int32_t msgLen, tmsg_t msgType, int64_t ver)
         };
         qStreamSetScanMemData(task, submit);
 
-        // exec
+        // here start to scan submit block to extract the subscribed data
         while (1) {
           SSDataBlock* pDataBlock = NULL;
           uint64_t     ts = 0;
@@ -278,7 +283,7 @@ int tqPushMsg(STQ* pTq, void* msg, int32_t msgLen, tmsg_t msgType, int64_t ver)
           pRsp->blockNum++;
         }
 
-        tqDebug("vgId:%d, tq handle push, subkey: %s, block num: %d", pTq->pVnode->config.vgId, pPushEntry->subKey,
+        tqDebug("vgId:%d, tq handle push, subkey:%s, block num:%d", pTq->pVnode->config.vgId, pPushEntry->subKey,
                 pRsp->blockNum);
         if (pRsp->blockNum > 0) {
           // set offset
@@ -295,6 +300,7 @@ int tqPushMsg(STQ* pTq, void* msg, int32_t msgLen, tmsg_t msgType, int64_t ver)
           tqPushDataRsp(pTq, pPushEntry);
         }
       }
+
       // delete entry
       for (int32_t i = 0; i < taosArrayGetSize(cachedKeys); i++) {
         void*  key = taosArrayGetP(cachedKeys, i);
diff --git a/source/dnode/vnode/src/tq/tqRead.c b/source/dnode/vnode/src/tq/tqRead.c
index 2c8f20d8cd96432b943d4db208e17bc843dac836..5352ebe6d4b5a3aa00e963c951f683def7586813 100644
--- a/source/dnode/vnode/src/tq/tqRead.c
+++ b/source/dnode/vnode/src/tq/tqRead.c
@@ -291,10 +291,15 @@ void tqCloseReader(STqReader* pReader) {
 }
 
 int32_t tqSeekVer(STqReader* pReader, int64_t ver) {
+  // todo set the correct vgId
+  tqDebug("tmq poll: vgId:%d wal seek to version:%"PRId64, 0, ver);
   if (walReadSeekVer(pReader->pWalReader, ver) < 0) {
+    tqError("tmq poll: wal reader failed to seek to ver:%"PRId64, ver);
     return -1;
+  } else {
+    tqDebug("tmq poll: wal reader seek to ver:%"PRId64, ver);
+    return 0;
   }
-  return 0;
 }
 
 int32_t tqNextBlock(STqReader* pReader, SFetchRet* ret) {
@@ -302,28 +307,33 @@ int32_t tqNextBlock(STqReader* pReader, SFetchRet* ret) {
 
   while (1) {
     if (!fromProcessedMsg) {
-      if (walNextValidMsg(pReader->pWalReader) < 0) {
-        pReader->ver =
-            pReader->pWalReader->curVersion - (pReader->pWalReader->curInvalid | pReader->pWalReader->curStopped);
+      SWalReader* pWalReader = pReader->pWalReader;
+
+      if (walNextValidMsg(pWalReader) < 0) {
+        pReader->ver = pWalReader->curVersion - (pWalReader->curInvalid | pWalReader->curStopped);
         ret->offset.type = TMQ_OFFSET__LOG;
         ret->offset.version = pReader->ver;
         ret->fetchType = FETCH_TYPE__NONE;
         tqDebug("return offset %" PRId64 ", no more valid", ret->offset.version);
         return -1;
       }
-      void*   body = POINTER_SHIFT(pReader->pWalReader->pHead->head.body, sizeof(SSubmitReq2Msg));
-      int32_t bodyLen = pReader->pWalReader->pHead->head.bodyLen - sizeof(SSubmitReq2Msg);
-      int64_t ver = pReader->pWalReader->pHead->head.version;
+
+      void*   body = POINTER_SHIFT(pWalReader->pHead->head.body, sizeof(SSubmitReq2Msg));
+      int32_t bodyLen = pWalReader->pHead->head.bodyLen - sizeof(SSubmitReq2Msg);
+      int64_t ver = pWalReader->pHead->head.version;
+
+      tqDebug("tmq poll: extract submit msg from wal, version:%"PRId64" len:%d", ver, bodyLen);
+
 #if 0
-      if (pReader->pWalReader->pHead->head.msgType != TDMT_VND_SUBMIT) {
+      if (pWalReader->pHead->head.msgType != TDMT_VND_SUBMIT) {
         // TODO do filter
         ret->fetchType = FETCH_TYPE__META;
-        ret->meta = pReader->pWalReader->pHead->head.body;
+        ret->meta = pWalReader->pHead->head.body;
         return 0;
       } else {
 #endif
       tqReaderSetSubmitReq2(pReader, body, bodyLen, ver);
-      /*tqReaderSetDataMsg(pReader, body, pReader->pWalReader->pHead->head.version);*/
+      /*tqReaderSetDataMsg(pReader, body, pWalReader->pHead->head.version);*/
 #if 0
       }
 #endif
@@ -358,7 +368,7 @@ int32_t tqReaderSetDataMsg(STqReader* pReader, const SSubmitReq* pMsg, int64_t v
 //  if (tInitSubmitMsgIter(pMsg, &pReader->msgIter) < 0) return -1;
 //  while (true) {
 //    if (tGetSubmitMsgNext(&pReader->msgIter, &pReader->pBlock) < 0) return -1;
-//    tqDebug("submitnext vgId:%d, block:%p, dataLen:%d, len:%d, uid:%"PRId64, pReader->pWalReader->pWal->cfg.vgId, pReader->pBlock, pReader->msgIter.dataLen,
+//    tqDebug("submitnext vgId:%d, block:%p, dataLen:%d, len:%d, uid:%"PRId64, pWalReader->pWal->cfg.vgId, pReader->pBlock, pReader->msgIter.dataLen,
 //            pReader->msgIter.len, pReader->msgIter.uid);
 //    if (pReader->pBlock == NULL) break;
 //  }
@@ -371,10 +381,8 @@ int32_t tqReaderSetDataMsg(STqReader* pReader, const SSubmitReq* pMsg, int64_t v
 #endif
 
 int32_t tqReaderSetSubmitReq2(STqReader* pReader, void* msgStr, int32_t msgLen, int64_t ver) {
-  ASSERT(pReader->msg2.msgStr == NULL);
-  ASSERT(msgStr);
-  ASSERT(msgLen);
-  ASSERT(ver >= 0);
+  ASSERT(pReader->msg2.msgStr == NULL && msgStr && msgLen && (ver >= 0));
+
   pReader->msg2.msgStr = msgStr;
   pReader->msg2.msgLen = msgLen;
   pReader->msg2.ver = ver;
@@ -421,7 +429,10 @@ bool tqNextDataBlock(STqReader* pReader) {
 #endif
 
 bool tqNextDataBlock2(STqReader* pReader) {
-  if (pReader->msg2.msgStr == NULL) return false;
+  if (pReader->msg2.msgStr == NULL) {
+    return false;
+  }
+
   ASSERT(pReader->setMsg == 1);
 
   tqDebug("tq reader next data block %p, %d %" PRId64 " %d", pReader->msg2.msgStr, pReader->msg2.msgLen,
@@ -528,7 +539,7 @@ int32_t tqScanSubmitSplit(SArray* pBlocks, SArray* schemas, STqReader* pReader)
     if (pReader->pSchema == NULL) {
       tqWarn("vgId:%d, cannot found tsschema for table: uid:%" PRId64 " (suid:%" PRId64
              "), version %d, possibly dropped table",
-             pReader->pWalReader->pWal->cfg.vgId, pReader->msgIter.uid, pReader->msgIter.suid, sversion);
+             pWalReader->pWal->cfg.vgId, pReader->msgIter.uid, pReader->msgIter.suid, sversion);
       pReader->cachedSchemaSuid = 0;
       terrno = TSDB_CODE_TQ_TABLE_SCHEMA_NOT_FOUND;
       return -1;
@@ -538,7 +549,7 @@ int32_t tqScanSubmitSplit(SArray* pBlocks, SArray* schemas, STqReader* pReader)
     pReader->pSchemaWrapper = metaGetTableSchema(pReader->pVnodeMeta, pReader->msgIter.uid, sversion, 1);
     if (pReader->pSchemaWrapper == NULL) {
       tqWarn("vgId:%d, cannot found schema wrapper for table: suid:%" PRId64 ", version %d, possibly dropped table",
-             pReader->pWalReader->pWal->cfg.vgId, pReader->msgIter.uid, pReader->cachedSchemaVer);
+             pWalReader->pWal->cfg.vgId, pReader->msgIter.uid, pReader->cachedSchemaVer);
       pReader->cachedSchemaSuid = 0;
       terrno = TSDB_CODE_TQ_TABLE_SCHEMA_NOT_FOUND;
       return -1;
diff --git a/source/dnode/vnode/src/vnd/vnodeSvr.c b/source/dnode/vnode/src/vnd/vnodeSvr.c
index 28aa65acd3405d8a1e1551ff20521f9c478e4b8b..192a3615e14c064753bf12f0376b55e7f5b09bb6 100644
--- a/source/dnode/vnode/src/vnd/vnodeSvr.c
+++ b/source/dnode/vnode/src/vnd/vnodeSvr.c
@@ -1273,8 +1273,8 @@ static int32_t vnodeProcessSubmitReq(SVnode *pVnode, int64_t version, void *pReq
         goto _exit;
       }
 
-      for (int32_t i = 1; i < nColData; i++) {
-        if (aColData[i].nVal != aColData[0].nVal) {
+      for (int32_t j = 1; j < nColData; j++) {
+        if (aColData[j].nVal != aColData[0].nVal) {
           code = TSDB_CODE_INVALID_MSG;
           goto _exit;
         }
@@ -1308,8 +1308,8 @@ static int32_t vnodeProcessSubmitReq(SVnode *pVnode, int64_t version, void *pReq
       SVCreateTbRsp *pCreateTbRsp = taosArrayReserve(pSubmitRsp->aCreateTbRsp, 1);
 
       // create table
-      if (metaCreateTable(pVnode->pMeta, version, pSubmitTbData->pCreateTbReq, &pCreateTbRsp->pMeta) ==
-          0) {  // create table success
+      if (metaCreateTable(pVnode->pMeta, version, pSubmitTbData->pCreateTbReq, &pCreateTbRsp->pMeta) == 0) {
+        // create table success
 
         if (newTbUids == NULL &&
             (newTbUids = taosArrayInit(TARRAY_SIZE(pSubmitReq->aSubmitTbData), sizeof(int64_t))) == NULL) {
@@ -1339,7 +1339,7 @@ static int32_t vnodeProcessSubmitReq(SVnode *pVnode, int64_t version, void *pReq
     pSubmitRsp->affectedRows += affectedRows;
   }
 
-  // update table uid list
+  // update the affected table uid list
   if (taosArrayGetSize(newTbUids) > 0) {
     vDebug("vgId:%d, add %d table into query table list in handling submit", TD_VID(pVnode),
            (int32_t)taosArrayGetSize(newTbUids));
diff --git a/source/libs/executor/inc/executorimpl.h b/source/libs/executor/inc/executorimpl.h
index 1712cba0f53ac3e3f5cf69d3ad8e257851fd55f0..5df3b14a5b1bedd6a75971320fc4e0560eb70527 100644
--- a/source/libs/executor/inc/executorimpl.h
+++ b/source/libs/executor/inc/executorimpl.h
@@ -133,8 +133,7 @@ typedef struct {
   int64_t      snapshotVer;
   // const SSubmitReq* pReq;
 
-  SPackedData submit;
-
+  SPackedData         submit;
   SSchemaWrapper*     schema;
   char                tbName[TSDB_TABLE_NAME_LEN];
   int8_t              recoverStep;
diff --git a/source/libs/executor/src/executil.c b/source/libs/executor/src/executil.c
index 6b6f5cfe93a3e3ffd89c9f277d41a5dd4ee92743..9537751ff0f4dccd96ec9d5f045cdd33b350a880 100644
--- a/source/libs/executor/src/executil.c
+++ b/source/libs/executor/src/executil.c
@@ -850,32 +850,32 @@ static SSDataBlock* createTagValBlockForFilter(SArray* pColList, int32_t numOfTa
         tagVal.cid = pColInfo->info.colId;
         if (p1->pTagVal == NULL) {
           colDataSetNULL(pColInfo, i);
-        }
-
-        const char* p = metaGetTableTagVal(p1->pTagVal, pColInfo->info.type, &tagVal);
-
-        if (p == NULL || (pColInfo->info.type == TSDB_DATA_TYPE_JSON && ((STag*)p)->nTag == 0)) {
-          colDataSetNULL(pColInfo, i);
-        } else if (pColInfo->info.type == TSDB_DATA_TYPE_JSON) {
-          colDataSetVal(pColInfo, i, p, false);
-        } else if (IS_VAR_DATA_TYPE(pColInfo->info.type)) {
-          char* tmp = taosMemoryMalloc(tagVal.nData + VARSTR_HEADER_SIZE + 1);
-          varDataSetLen(tmp, tagVal.nData);
-          memcpy(tmp + VARSTR_HEADER_SIZE, tagVal.pData, tagVal.nData);
-          colDataSetVal(pColInfo, i, tmp, false);
+        } else {
+          const char* p = metaGetTableTagVal(p1->pTagVal, pColInfo->info.type, &tagVal);
+
+          if (p == NULL || (pColInfo->info.type == TSDB_DATA_TYPE_JSON && ((STag*)p)->nTag == 0)) {
+            colDataSetNULL(pColInfo, i);
+          } else if (pColInfo->info.type == TSDB_DATA_TYPE_JSON) {
+            colDataSetVal(pColInfo, i, p, false);
+          } else if (IS_VAR_DATA_TYPE(pColInfo->info.type)) {
+            char* tmp = taosMemoryMalloc(tagVal.nData + VARSTR_HEADER_SIZE + 1);
+            varDataSetLen(tmp, tagVal.nData);
+            memcpy(tmp + VARSTR_HEADER_SIZE, tagVal.pData, tagVal.nData);
+            colDataSetVal(pColInfo, i, tmp, false);
 #if TAG_FILTER_DEBUG
-          qDebug("tagfilter varch:%s", tmp + 2);
+            qDebug("tagfilter varch:%s", tmp + 2);
 #endif
-          taosMemoryFree(tmp);
-        } else {
-          colDataSetVal(pColInfo, i, (const char*)&tagVal.i64, false);
+            taosMemoryFree(tmp);
+          } else {
+            colDataSetVal(pColInfo, i, (const char*)&tagVal.i64, false);
 #if TAG_FILTER_DEBUG
-          if (pColInfo->info.type == TSDB_DATA_TYPE_INT) {
-            qDebug("tagfilter int:%d", *(int*)(&tagVal.i64));
-          } else if (pColInfo->info.type == TSDB_DATA_TYPE_DOUBLE) {
-            qDebug("tagfilter double:%f", *(double*)(&tagVal.i64));
-          }
+            if (pColInfo->info.type == TSDB_DATA_TYPE_INT) {
+              qDebug("tagfilter int:%d", *(int*)(&tagVal.i64));
+            } else if (pColInfo->info.type == TSDB_DATA_TYPE_DOUBLE) {
+              qDebug("tagfilter double:%f", *(double*)(&tagVal.i64));
+            }
 #endif
+          }
         }
       }
     }
diff --git a/source/libs/executor/src/executor.c b/source/libs/executor/src/executor.c
index 347ac369d883deae5104495e033f8c191962f032..c2bf001c86d4af8fffccd544c2b4de70798f870a 100644
--- a/source/libs/executor/src/executor.c
+++ b/source/libs/executor/src/executor.c
@@ -1035,8 +1035,9 @@ int32_t qStreamScanMemData(qTaskInfo_t tinfo, const SSubmitReq* pReq, int64_t sc
 
 int32_t qStreamSetScanMemData(qTaskInfo_t tinfo, SPackedData submit) {
   SExecTaskInfo* pTaskInfo = (SExecTaskInfo*)tinfo;
-  ASSERT(pTaskInfo->execModel == OPTR_EXEC_MODEL_QUEUE);
-  ASSERT(pTaskInfo->streamInfo.submit.msgStr == NULL);
+  ASSERT((pTaskInfo->execModel == OPTR_EXEC_MODEL_QUEUE )&& (pTaskInfo->streamInfo.submit.msgStr == NULL));
+  qDebug("set the submit block for future scan");
+
   pTaskInfo->streamInfo.submit = submit;
   return 0;
 }
@@ -1047,14 +1048,16 @@ int32_t qStreamPrepareScan(qTaskInfo_t tinfo, STqOffsetVal* pOffset, int8_t subT
   ASSERT(pTaskInfo->execModel == OPTR_EXEC_MODEL_QUEUE);
   pTaskInfo->streamInfo.prepareStatus = *pOffset;
   pTaskInfo->streamInfo.returned = 0;
+
   if (tOffsetEqual(pOffset, &pTaskInfo->streamInfo.lastStatus)) {
     return 0;
   }
+
   if (subType == TOPIC_SUB_TYPE__COLUMN) {
-    uint16_t type = pOperator->operatorType;
     pOperator->status = OP_OPENED;
+
     // TODO add more check
-    if (type != QUERY_NODE_PHYSICAL_PLAN_STREAM_SCAN) {
+    if (pOperator->operatorType != QUERY_NODE_PHYSICAL_PLAN_STREAM_SCAN) {
       ASSERT(pOperator->numOfDownstream == 1);
       pOperator = pOperator->pDownstream[0];
     }
@@ -1064,11 +1067,13 @@ int32_t qStreamPrepareScan(qTaskInfo_t tinfo, STqOffsetVal* pOffset, int8_t subT
       STableScanInfo* pTSInfo = pInfo->pTableScanOp->info;
       tsdbReaderClose(pTSInfo->base.dataReader);
       pTSInfo->base.dataReader = NULL;
+      // let's seek to the next version in wal file
       if (tqSeekVer(pInfo->tqReader, pOffset->version + 1) < 0) {
         return -1;
       }
     } else if (pOffset->type == TMQ_OFFSET__SNAPSHOT_DATA) {
-      /*pInfo->blockType = STREAM_INPUT__TABLE_SCAN;*/
+      // iterate all tables from tableInfoList, and retrieve rows from each table one-by-one
+      // those data are from the snapshot in tsdb, besides the data in the wal file.
       int64_t uid = pOffset->uid;
       int64_t ts = pOffset->ts;
 
@@ -1127,7 +1132,6 @@ int32_t qStreamPrepareScan(qTaskInfo_t tinfo, STqOffsetVal* pOffset, int8_t subT
 
       qDebug("tsdb reader offset seek to uid %" PRId64 " ts %" PRId64 ", table cur set to %d , all table num %d", uid,
              ts, pTableScanInfo->currentTable, numOfTables);
-      /*}*/
     } else {
       ASSERT(0);
     }
@@ -1170,7 +1174,7 @@ int32_t qStreamPrepareScan(qTaskInfo_t tinfo, STqOffsetVal* pOffset, int8_t subT
     tDeleteSSchemaWrapper(pTaskInfo->streamInfo.schema);
     pTaskInfo->streamInfo.schema = mtInfo.schema;
 
-    qDebug("tmqsnap qStreamPrepareScan snapshot data uid %" PRId64 " ts %" PRId64, mtInfo.uid, pOffset->ts);
+    qDebug("tmqsnap qStreamPrepareScan snapshot data uid:%" PRId64 " ts %" PRId64, mtInfo.uid, pOffset->ts);
   } else if (pOffset->type == TMQ_OFFSET__SNAPSHOT_META) {
     SStreamRawScanInfo* pInfo = pOperator->info;
     SSnapContext*       sContext = pInfo->sContext;
@@ -1178,7 +1182,7 @@ int32_t qStreamPrepareScan(qTaskInfo_t tinfo, STqOffsetVal* pOffset, int8_t subT
       qError("setForSnapShot error. uid:%" PRIu64 " ,version:%" PRId64, pOffset->uid, pOffset->version);
       return -1;
     }
-    qDebug("tmqsnap qStreamPrepareScan snapshot meta uid %" PRId64 " ts %" PRId64, pOffset->uid, pOffset->ts);
+    qDebug("tmqsnap qStreamPrepareScan snapshot meta uid:%" PRId64 " ts %" PRId64, pOffset->uid, pOffset->ts);
   } else if (pOffset->type == TMQ_OFFSET__LOG) {
     SStreamRawScanInfo* pInfo = pOperator->info;
     tsdbReaderClose(pInfo->dataReader);
diff --git a/source/libs/executor/src/scanoperator.c b/source/libs/executor/src/scanoperator.c
index a238b84993e5d3b07a31caba108e82ebd44a3f39..e1594b13a8a3c5575c67f0d134e3ef18b2bd53ee 100644
--- a/source/libs/executor/src/scanoperator.c
+++ b/source/libs/executor/src/scanoperator.c
@@ -1562,7 +1562,7 @@ static SSDataBlock* doQueueScan(SOperatorInfo* pOperator) {
   SExecTaskInfo*   pTaskInfo = pOperator->pTaskInfo;
   SStreamScanInfo* pInfo = pOperator->info;
 
-  qDebug("queue scan called");
+  qDebug("start to exec queue scan");
 
   if (pTaskInfo->streamInfo.submit.msgStr != NULL) {
     if (pInfo->tqReader->msg2.msgStr == NULL) {
@@ -1587,7 +1587,6 @@ static SSDataBlock* doQueueScan(SOperatorInfo* pOperator) {
       SSDataBlock block = {0};
 
       int32_t code = tqRetrieveDataBlock2(&block, pInfo->tqReader, NULL);
-
       if (code != TSDB_CODE_SUCCESS || block.info.rows == 0) {
         continue;
       }
diff --git a/source/libs/nodes/src/nodesUtilFuncs.c b/source/libs/nodes/src/nodesUtilFuncs.c
index 0419c883e6320aea75743f9106a65606668e21a4..024130b5f8eb0689f86fb12e968f54189c5f4dfc 100644
--- a/source/libs/nodes/src/nodesUtilFuncs.c
+++ b/source/libs/nodes/src/nodesUtilFuncs.c
@@ -2101,9 +2101,9 @@ void nodesValueNodeToVariant(const SValueNode* pNode, SVariant* pVal) {
     case TSDB_DATA_TYPE_NCHAR:
     case TSDB_DATA_TYPE_VARCHAR:
     case TSDB_DATA_TYPE_VARBINARY:
-      pVal->pz = taosMemoryMalloc(pVal->nLen + VARSTR_HEADER_SIZE + 1);
-      memcpy(pVal->pz, pNode->datum.p, pVal->nLen + VARSTR_HEADER_SIZE);
-      pVal->pz[pVal->nLen + VARSTR_HEADER_SIZE] = 0;
+      pVal->pz = taosMemoryMalloc(pVal->nLen + 1);
+      memcpy(pVal->pz, pNode->datum.p, pVal->nLen);
+      pVal->pz[pVal->nLen] = 0;
       break;
     case TSDB_DATA_TYPE_JSON:
       pVal->nLen = getJsonValueLen(pNode->datum.p);
diff --git a/source/util/src/thashutil.c b/source/util/src/thashutil.c
index 21b9359076078900196769046b54ff31fd88b0e4..f9c7eb1f5687440d5156d1999741ef777774aa67 100644
--- a/source/util/src/thashutil.c
+++ b/source/util/src/thashutil.c
@@ -50,11 +50,6 @@ uint32_t taosDJB2Hash(const char *key, uint32_t len) {
   return hash;
 }
 
-uint32_t xxHash(const char *key, uint32_t len) {
-  int32_t seed = 0xcc9e2d51;
-  return XXH32(key, len, seed);
-}
-
 uint32_t MurmurHash3_32(const char *key, uint32_t len) {
   const uint8_t *data = (const uint8_t *)key;
   const int32_t  nblocks = len >> 2u;