diff --git a/examples/rust b/examples/rust
deleted file mode 160000
index 7ed7a97715388fa144718764d6bf20f9bfc29a12..0000000000000000000000000000000000000000
--- a/examples/rust
+++ /dev/null
@@ -1 +0,0 @@
-Subproject commit 7ed7a97715388fa144718764d6bf20f9bfc29a12
diff --git a/include/util/taoserror.h b/include/util/taoserror.h
index ce73dceec22a51e869f331c918e8775fdbf357b1..3ca6978156bb99d40245bd89c09981786c3b8d46 100644
--- a/include/util/taoserror.h
+++ b/include/util/taoserror.h
@@ -284,11 +284,13 @@ int32_t* taosGetErrno();
 #define TSDB_CODE_MND_CONSUMER_NOT_READY        TAOS_DEF_ERROR_CODE(0, 0x03EA)
 #define TSDB_CODE_MND_TOPIC_SUBSCRIBED          TAOS_DEF_ERROR_CODE(0, 0x03EB)
 #define TSDB_CODE_MND_CGROUP_USED               TAOS_DEF_ERROR_CODE(0, 0x03EC)
+#define TSDB_CODE_MND_TOPIC_MUST_BE_DELETED     TAOS_DEF_ERROR_CODE(0, 0x03ED)
 
 // mnode-stream
 #define TSDB_CODE_MND_STREAM_ALREADY_EXIST      TAOS_DEF_ERROR_CODE(0, 0x03F0)
 #define TSDB_CODE_MND_STREAM_NOT_EXIST          TAOS_DEF_ERROR_CODE(0, 0x03F1)
 #define TSDB_CODE_MND_INVALID_STREAM_OPTION     TAOS_DEF_ERROR_CODE(0, 0x03F2)
+#define TSDB_CODE_MND_STREAM_MUST_BE_DELETED    TAOS_DEF_ERROR_CODE(0, 0x03F3)
 
 // mnode-sma
 #define TSDB_CODE_MND_SMA_ALREADY_EXIST         TAOS_DEF_ERROR_CODE(0, 0x0480)
diff --git a/source/client/src/tmq.c b/source/client/src/tmq.c
index c4375c85b4fc7eaf774fdf3bb4aa1ffde11cfa06..c0874caf950de1bbcfadef4ce0c5bc9409450dc3 100644
--- a/source/client/src/tmq.c
+++ b/source/client/src/tmq.c
@@ -204,7 +204,7 @@ typedef struct {
 typedef struct {
   SMqCommitCbParamSet* params;
   STqOffset*           pOffset;
-} SMqCommitCbParam2;
+} SMqCommitCbParam;
 
 tmq_conf_t* tmq_conf_new() {
   tmq_conf_t* conf = taosMemoryCalloc(1, sizeof(tmq_conf_t));
@@ -368,8 +368,8 @@ static int32_t tmqMakeTopicVgKey(char* dst, const char* topicName, int32_t vg) {
   return sprintf(dst, "%s:%d", topicName, vg);
 }
 
-int32_t tmqCommitCb2(void* param, SDataBuf* pBuf, int32_t code) {
-  SMqCommitCbParam2*   pParam = (SMqCommitCbParam2*)param;
+int32_t tmqCommitCb(void* param, SDataBuf* pBuf, int32_t code) {
+  SMqCommitCbParam*    pParam = (SMqCommitCbParam*)param;
   SMqCommitCbParamSet* pParamSet = (SMqCommitCbParamSet*)pParam->params;
   // push into array
 #if 0
@@ -440,7 +440,7 @@ static int32_t tmqSendCommitReq(tmq_t* tmq, SMqClientVg* pVg, SMqClientTopic* pT
   tEncodeSTqOffset(&encoder, pOffset);
 
   // build param
-  SMqCommitCbParam2* pParam = taosMemoryCalloc(1, sizeof(SMqCommitCbParam2));
+  SMqCommitCbParam* pParam = taosMemoryCalloc(1, sizeof(SMqCommitCbParam));
   pParam->params = pParamSet;
   pParam->pOffset = pOffset;
 
@@ -465,7 +465,7 @@ static int32_t tmqSendCommitReq(tmq_t* tmq, SMqClientVg* pVg, SMqClientTopic* pT
   pMsgSendInfo->requestObjRefId = 0;
   pMsgSendInfo->param = pParam;
   pMsgSendInfo->paramFreeFp = taosMemoryFree;
-  pMsgSendInfo->fp = tmqCommitCb2;
+  pMsgSendInfo->fp = tmqCommitCb;
   pMsgSendInfo->msgType = TDMT_VND_MQ_COMMIT_OFFSET;
   // send msg
 
@@ -1313,17 +1313,6 @@ int32_t tmq_seek(tmq_t* tmq, const tmq_topic_vgroup_t* offset) {
 #endif
 
 SMqPollReq* tmqBuildConsumeReqImpl(tmq_t* tmq, int64_t timeout, SMqClientTopic* pTopic, SMqClientVg* pVg) {
-  /*int64_t reqOffset;*/
-  /*if (pVg->currentOffset >= 0) {*/
-  /*reqOffset = pVg->currentOffset;*/
-  /*} else {*/
-  /*if (tmq->resetOffsetCfg == TMQ_CONF__RESET_OFFSET__NONE) {*/
-  /*tscError("unable to poll since no committed offset but reset offset is set to none");*/
-  /*return NULL;*/
-  /*}*/
-  /*reqOffset = tmq->resetOffsetCfg;*/
-  /*}*/
-
   SMqPollReq* pReq = taosMemoryCalloc(1, sizeof(SMqPollReq));
   if (pReq == NULL) {
     return NULL;
diff --git a/source/dnode/mnode/impl/inc/mndTopic.h b/source/dnode/mnode/impl/inc/mndTopic.h
index c5c4800e0295fa48ee4bf9669200f7ce7a31eff8..9f516904ce816a6c7999d44ed003d064f36e95c5 100644
--- a/source/dnode/mnode/impl/inc/mndTopic.h
+++ b/source/dnode/mnode/impl/inc/mndTopic.h
@@ -32,6 +32,7 @@ SSdbRaw *mndTopicActionEncode(SMqTopicObj *pTopic);
 SSdbRow *mndTopicActionDecode(SSdbRaw *pRaw);
 
 int32_t mndDropTopicByDB(SMnode *pMnode, STrans *pTrans, SDbObj *pDb);
+int32_t mndCheckTopicExist(SMnode *pMnode, SDbObj *pDb);
 
 const char *mndTopicGetShowName(const char topic[TSDB_TOPIC_FNAME_LEN]);
 
diff --git a/source/dnode/mnode/impl/src/mndDb.c b/source/dnode/mnode/impl/src/mndDb.c
index 89ea7abc23be102210e36450302d5aa30c49e6a6..9dde083f5054c6557f7dd85049133f44c46522f6 100644
--- a/source/dnode/mnode/impl/src/mndDb.c
+++ b/source/dnode/mnode/impl/src/mndDb.c
@@ -995,11 +995,13 @@ static int32_t mndDropDb(SMnode *pMnode, SRpcMsg *pReq, SDbObj *pDb) {
   mDebug("trans:%d, used to drop db:%s", pTrans->id, pDb->name);
   mndTransSetDbName(pTrans, pDb->name, NULL);
 
+  if (mndCheckTopicExist(pMnode, pDb) < 0) goto _OVER;
+
   if (mndSetDropDbRedoLogs(pMnode, pTrans, pDb) != 0) goto _OVER;
   if (mndSetDropDbCommitLogs(pMnode, pTrans, pDb) != 0) goto _OVER;
-  if (mndDropOffsetByDB(pMnode, pTrans, pDb) != 0) goto _OVER;
-  if (mndDropSubByDB(pMnode, pTrans, pDb) != 0) goto _OVER;
-  if (mndDropTopicByDB(pMnode, pTrans, pDb) != 0) goto _OVER;
+  /*if (mndDropOffsetByDB(pMnode, pTrans, pDb) != 0) goto _OVER;*/
+  /*if (mndDropSubByDB(pMnode, pTrans, pDb) != 0) goto _OVER;*/
+  /*if (mndDropTopicByDB(pMnode, pTrans, pDb) != 0) goto _OVER;*/
   if (mndDropStreamByDb(pMnode, pTrans, pDb) != 0) goto _OVER;
   if (mndDropSmasByDb(pMnode, pTrans, pDb) != 0) goto _OVER;
   if (mndSetDropDbRedoActions(pMnode, pTrans, pDb) != 0) goto _OVER;
@@ -1706,7 +1708,7 @@ static void setPerfSchemaDbCfg(SDbObj *pDbObj) {
 static bool mndGetTablesOfDbFp(SMnode *pMnode, void *pObj, void *p1, void *p2, void *p3) {
   SVgObj  *pVgroup = pObj;
   int32_t *numOfTables = p1;
-  int64_t uid = *(int64_t*)p2;
+  int64_t  uid = *(int64_t *)p2;
   if (pVgroup->dbUid == uid) {
     *numOfTables += pVgroup->numOfTables;
   }
diff --git a/source/dnode/mnode/impl/src/mndStream.c b/source/dnode/mnode/impl/src/mndStream.c
index 7bde05aca5047195ed02a88ccb01e849daed2646..0f20188033b3f97c850d5a9f0075fc0fa8c58e6d 100644
--- a/source/dnode/mnode/impl/src/mndStream.c
+++ b/source/dnode/mnode/impl/src/mndStream.c
@@ -837,7 +837,7 @@ int32_t mndDropStreamByDb(SMnode *pMnode, STrans *pTrans, SDbObj *pDb) {
         sdbCancelFetch(pSdb, pIter);
         mError("db:%s, failed to drop stream:%s since sourceDbUid:%" PRId64 " not match with targetDbUid:%" PRId64,
                pDb->name, pStream->name, pStream->sourceDbUid, pStream->targetDbUid);
-        terrno = TSDB_CODE_MND_STREAM_ALREADY_EXIST;
+        terrno = TSDB_CODE_MND_STREAM_MUST_BE_DELETED;
         return -1;
       } else {
 #if 0
diff --git a/source/dnode/mnode/impl/src/mndTopic.c b/source/dnode/mnode/impl/src/mndTopic.c
index f343c2e055ed3f357a6a9cee6e3e1c8025d055cc..820bb4b636bf5ecdebdb55ead48eb9c7ee5aeca5 100644
--- a/source/dnode/mnode/impl/src/mndTopic.c
+++ b/source/dnode/mnode/impl/src/mndTopic.c
@@ -782,6 +782,26 @@ static void mndCancelGetNextTopic(SMnode *pMnode, void *pIter) {
   sdbCancelFetch(pSdb, pIter);
 }
 
+int32_t mndCheckTopicExist(SMnode *pMnode, SDbObj *pDb) {
+  SSdb *pSdb = pMnode->pSdb;
+
+  void        *pIter = NULL;
+  SMqTopicObj *pTopic = NULL;
+  while (1) {
+    pIter = sdbFetch(pSdb, SDB_TOPIC, pIter, (void **)&pTopic);
+    if (pIter == NULL) break;
+
+    if (pTopic->dbUid == pDb->uid) {
+      sdbRelease(pSdb, pTopic);
+      terrno = TSDB_CODE_MND_TOPIC_MUST_BE_DELETED;
+      return -1;
+    }
+
+    sdbRelease(pSdb, pTopic);
+  }
+  return 0;
+}
+
 int32_t mndDropTopicByDB(SMnode *pMnode, STrans *pTrans, SDbObj *pDb) {
   int32_t code = 0;
   SSdb   *pSdb = pMnode->pSdb;
diff --git a/source/util/src/terror.c b/source/util/src/terror.c
index f0a58c9bdc34cd307f499749ed36babfd95c6b0b..bb26f9b2f7fe8f69e7f4d7454e414abfcd6cccfb 100644
--- a/source/util/src/terror.c
+++ b/source/util/src/terror.c
@@ -286,6 +286,7 @@ TAOS_DEFINE_ERROR(TSDB_CODE_MND_SUBSCRIBE_NOT_EXIST,      "Subcribe not exist")
 TAOS_DEFINE_ERROR(TSDB_CODE_MND_OFFSET_NOT_EXIST,         "Offset not exist")
 TAOS_DEFINE_ERROR(TSDB_CODE_MND_CONSUMER_NOT_READY,       "Consumer not ready")
 TAOS_DEFINE_ERROR(TSDB_CODE_MND_TOPIC_SUBSCRIBED,         "Topic subscribed cannot be dropped")
+TAOS_DEFINE_ERROR(TSDB_CODE_MND_TOPIC_MUST_BE_DELETED,    "Topic must be dropped first")
 TAOS_DEFINE_ERROR(TSDB_CODE_MND_CGROUP_USED,              "Consumer group being used by some consumer")
 
 // mnode-stream
diff --git a/tools/taos-tools b/tools/taos-tools
deleted file mode 160000
index 3c7dafeea3e558968165b73bee0f51024898e3da..0000000000000000000000000000000000000000
--- a/tools/taos-tools
+++ /dev/null
@@ -1 +0,0 @@
-Subproject commit 3c7dafeea3e558968165b73bee0f51024898e3da