diff --git a/include/common/tmsg.h b/include/common/tmsg.h
index f6bee57c94e1342b3aed88db1cd5829fe0f06511..a3d62cc52d6fec125d74765845e354040f9c9df7 100644
--- a/include/common/tmsg.h
+++ b/include/common/tmsg.h
@@ -1527,7 +1527,6 @@ typedef struct SMqSetCVgReq {
   SArray* tasks;  // SArray<SSubQueryMsg>
 } SMqSetCVgReq;
 
-
 static FORCE_INLINE int32_t tEncodeSMqSetCVgReq(void** buf, const SMqSetCVgReq* pReq) {
   int32_t tlen = 0;
   tlen += taosEncodeFixedI32(buf, pReq->vgId);
@@ -1552,6 +1551,39 @@ static FORCE_INLINE void* tDecodeSMqSetCVgReq(void* buf, SMqSetCVgReq* pReq) {
   return buf;
 }
 
+typedef struct SMqSetCVgRsp {
+  int32_t vgId;
+  int64_t consumerId;
+  char    topicName[TSDB_TOPIC_FNAME_LEN];
+  char    cGroup[TSDB_CONSUMER_GROUP_LEN];
+} SMqSetCVgRsp;
+
+typedef struct SMqCVConsumeReq {
+  int64_t reqId;
+  int64_t offset;
+  int64_t consumerId;
+  int64_t blockingTime;
+  char    topicName[TSDB_TOPIC_FNAME_LEN];
+  char    cgroup[TSDB_CONSUMER_GROUP_LEN];
+} SMqCVConsumeReq;
+
+typedef struct SMqConsumeRspBlock {
+  int32_t bodyLen;
+  char topicName[TSDB_TOPIC_FNAME_LEN];
+  char body[];
+} SMqConsumeRspBlock;
+
+typedef struct SMqCVConsumeRsp {
+  int64_t reqId;
+  int64_t clientId;
+  int64_t committedOffset;
+  int64_t receiveOffset;
+  int64_t rspOffset;
+  int32_t skipLogNum;
+  int32_t bodyLen;
+  char    topicName[TSDB_TOPIC_FNAME_LEN];
+  SMqConsumeRspBlock blocks[];
+} SMqCvConsumeRsp;
 
 #ifdef __cplusplus
 }
diff --git a/include/common/tmsgdef.h b/include/common/tmsgdef.h
index 93adc58eca97c93c9c3cbbcc6836908a12a55d0d..52fff978bc82594e39911f10c98d06a7824fb854 100644
--- a/include/common/tmsgdef.h
+++ b/include/common/tmsgdef.h
@@ -160,7 +160,7 @@ enum {
   TD_DEF_MSG_TYPE(TDMT_VND_MQ_QUERY, "vnode-mq-query", NULL, NULL)
   TD_DEF_MSG_TYPE(TDMT_VND_MQ_CONNECT, "vnode-mq-connect", NULL, NULL)
   TD_DEF_MSG_TYPE(TDMT_VND_MQ_DISCONNECT, "vnode-mq-disconnect", NULL, NULL)
-  TD_DEF_MSG_TYPE(TDMT_VND_MQ_SET_CONN, "vnode-mq-set-conn", NULL, NULL)
+  TD_DEF_MSG_TYPE(TDMT_VND_MQ_SET_CONN, "vnode-mq-set-conn", SMqSetCVgReq, SMqSetCVgRsp)
   TD_DEF_MSG_TYPE(TDMT_VND_MQ_SET_CUR, "vnode-mq-set-cur", NULL, NULL)
   TD_DEF_MSG_TYPE(TDMT_VND_RES_READY, "vnode-res-ready", NULL, NULL)
   TD_DEF_MSG_TYPE(TDMT_VND_TASKS_STATUS, "vnode-tasks-status", NULL, NULL)
@@ -175,6 +175,7 @@ enum {
   TD_DEF_MSG_TYPE(TDMT_VND_SCHEDULE_DATA_SINK, "vnode-schedule-data-sink", NULL, NULL)
 
   TD_DEF_MSG_TYPE(TDMT_VND_SUBSCRIBE, "vnode-subscribe", SMVSubscribeReq, SMVSubscribeRsp)
+  TD_DEF_MSG_TYPE(TDMT_VND_CONSUME, "vnode-consume", SMqCVConsumeReq, SMqCVConsumeRsp)
 
 
   // Requests handled by QNODE
diff --git a/include/libs/function/functionMgt.h b/include/libs/function/functionMgt.h
new file mode 100644
index 0000000000000000000000000000000000000000..3c365335be9f3dd4364a8ec849968df7a16ca792
--- /dev/null
+++ b/include/libs/function/functionMgt.h
@@ -0,0 +1,66 @@
+/*
+ * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
+ *
+ * This program is free software: you can use, redistribute, and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3
+ * or later ("AGPL"), as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _TD_FUNCTION_MGT_H_
+#define _TD_FUNCTION_MGT_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "nodes.h"
+
+struct SQLFunctionCtx;
+struct SResultRowEntryInfo;
+struct STimeWindow;
+
+typedef struct SFuncExecEnv {
+  int32_t calcMemSize;
+} SFuncExecEnv;
+
+typedef void* FuncMgtHandle;
+typedef bool (*FExecGetEnv)(SFunctionNode* pFunc, SFuncExecEnv* pEnv);
+typedef bool (*FExecInit)(struct SQLFunctionCtx *pCtx, struct SResultRowEntryInfo* pResultCellInfo);
+typedef void (*FExecProcess)(struct SQLFunctionCtx *pCtx);
+typedef void (*FExecFinalize)(struct SQLFunctionCtx *pCtx);
+
+typedef struct SFuncExecFuncs {
+  FExecGetEnv getEnv;
+  FExecInit init;
+  FExecProcess process;
+  FExecFinalize finalize;
+} SFuncExecFuncs;
+
+int32_t fmFuncMgtInit();
+
+int32_t fmGetHandle(FuncMgtHandle* pHandle);
+
+int32_t fmGetFuncId(FuncMgtHandle handle, const char* name);
+int32_t fmGetFuncResultType(FuncMgtHandle handle, SFunctionNode* pFunc);
+bool fmIsAggFunc(int32_t funcId);
+bool fmIsStringFunc(int32_t funcId);
+bool fmIsTimestampFunc(int32_t funcId);
+bool fmIsTimelineFunc(int32_t funcId);
+bool fmIsTimeorderFunc(int32_t funcId);
+bool fmIsNonstandardSQLFunc(int32_t funcId);
+int32_t fmFuncScanType(int32_t funcId);
+
+int32_t fmGetFuncExecFuncs(FuncMgtHandle handle, int32_t funcId, SFuncExecFuncs* pFpSet);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif  // _TD_FUNCTION_MGT_H_
diff --git a/include/libs/wal/wal.h b/include/libs/wal/wal.h
index 51aaa7d9038c992ed264632e8fd7a149a4220852..641b485f4c3daf46af866da7bd021403b1fbc5ee 100644
--- a/include/libs/wal/wal.h
+++ b/include/libs/wal/wal.h
@@ -80,8 +80,8 @@ typedef enum { TAOS_WAL_NOLOG = 0, TAOS_WAL_WRITE = 1, TAOS_WAL_FSYNC = 2 } EWal
 
 typedef struct SWalReadHead {
   int8_t  headVer;
-  uint8_t msgType;
-  int8_t  reserved[2];
+  int16_t msgType;
+  int8_t  reserved;
   int32_t len;
   int64_t ingestTs;  // not implemented
   int64_t version;
diff --git a/include/nodes/nodes.h b/include/nodes/nodes.h
new file mode 100644
index 0000000000000000000000000000000000000000..e6b41adf146a8a9e6881c8644398b150246e8ab1
--- /dev/null
+++ b/include/nodes/nodes.h
@@ -0,0 +1,271 @@
+/*
+ * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
+ *
+ * This program is free software: you can use, redistribute, and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3
+ * or later ("AGPL"), as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _TD_NODES_H_
+#define _TD_NODES_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "tarray.h"
+#include "tdef.h"
+
+typedef enum ENodeType {
+  QUERY_NODE_COLUMN = 1,
+  QUERY_NODE_VALUE,
+  QUERY_NODE_OPERATOR,
+  QUERY_NODE_LOGIC_CONDITION,
+  QUERY_NODE_IS_NULL_CONDITION,
+  QUERY_NODE_FUNCTION,
+  QUERY_NODE_REAL_TABLE,
+  QUERY_NODE_TEMP_TABLE,
+  QUERY_NODE_JOIN_TABLE,
+  QUERY_NODE_GROUPING_SET,
+  QUERY_NODE_ORDER_BY_EXPR,
+  QUERY_NODE_STATE_WINDOW,
+  QUERY_NODE_SESSION_WINDOW,
+  QUERY_NODE_INTERVAL_WINDOW,
+
+  QUERY_NODE_SET_OPERATOR,
+  QUERY_NODE_SELECT_STMT
+} ENodeType;
+
+/**
+ * The first field of a node of any type is guaranteed to be the ENodeType.
+ * Hence the type of any node can be gotten by casting it to SNode. 
+ */
+typedef struct SNode {
+  ENodeType type;
+} SNode;
+
+#define nodeType(nodeptr) (((const SNode*)(nodeptr))->type)
+
+typedef struct SDataType {
+  uint8_t type;
+  uint8_t precision;
+  uint8_t scale;
+  int32_t bytes;
+} SDataType;
+
+typedef struct SExprNode {
+  ENodeType nodeType;
+  SDataType resType;
+  char aliasName[TSDB_COL_NAME_LEN];
+} SExprNode;
+
+typedef enum EColumnType {
+  COLUMN_TYPE_COLUMN = 1,
+  COLUMN_TYPE_TAG
+} EColumnType;
+
+typedef struct SColumnNode {
+  SExprNode node; // QUERY_NODE_COLUMN
+  int16_t colId;
+  EColumnType colType; // column or tag
+  char dbName[TSDB_DB_NAME_LEN];
+  char tableName[TSDB_TABLE_NAME_LEN];
+  char colName[TSDB_COL_NAME_LEN];
+} SColumnNode;
+
+typedef struct SValueNode {
+  SExprNode type; // QUERY_NODE_VALUE
+  char* literal;
+} SValueNode;
+
+typedef enum EOperatorType {
+  // arithmetic operator
+  OP_TYPE_ADD = 1,
+  OP_TYPE_SUB,
+  OP_TYPE_MULTI,
+  OP_TYPE_DIV,
+  OP_TYPE_MOD,
+
+  // comparison operator
+  OP_TYPE_GREATER_THAN,
+  OP_TYPE_GREATER_EQUAL,
+  OP_TYPE_LOWER_THAN,
+  OP_TYPE_LOWER_EQUAL,
+  OP_TYPE_EQUAL,
+  OP_TYPE_NOT_EQUAL,
+  OP_TYPE_IN,
+  OP_TYPE_NOT_IN,
+  OP_TYPE_LIKE,
+  OP_TYPE_NOT_LIKE,
+  OP_TYPE_MATCH,
+  OP_TYPE_NMATCH,
+
+  // json operator
+  OP_TYPE_JSON_GET_VALUE,
+  OP_TYPE_JSON_CONTAINS
+} EOperatorType;
+
+typedef struct SOperatorNode {
+  SExprNode type; // QUERY_NODE_OPERATOR
+  EOperatorType opType;
+  SNode* pLeft;
+  SNode* pRight;
+} SOperatorNode;
+
+typedef enum ELogicConditionType {
+  LOGIC_COND_TYPE_AND,
+  LOGIC_COND_TYPE_OR,
+  LOGIC_COND_TYPE_NOT,
+} ELogicConditionType;
+
+typedef struct SLogicConditionNode {
+  ENodeType type; // QUERY_NODE_LOGIC_CONDITION
+  ELogicConditionType condType;
+  SArray* pParameterList;
+} SLogicConditionNode;
+
+typedef struct SIsNullCondNode {
+  ENodeType type; // QUERY_NODE_IS_NULL_CONDITION
+  SNode* pExpr;
+  bool isNot;
+} SIsNullCondNode;
+
+typedef struct SFunctionNode {
+  SExprNode type; // QUERY_NODE_FUNCTION
+  char functionName[TSDB_FUNC_NAME_LEN];
+  int32_t funcId;
+  SArray* pParameterList; // SNode
+} SFunctionNode;
+
+typedef struct STableNode {
+  ENodeType type;
+  char tableName[TSDB_TABLE_NAME_LEN];
+  char tableAliasName[TSDB_COL_NAME_LEN];
+} STableNode;
+
+typedef struct SRealTableNode {
+  STableNode type; // QUERY_NODE_REAL_TABLE
+  char dbName[TSDB_DB_NAME_LEN];
+} SRealTableNode;
+
+typedef struct STempTableNode {
+  STableNode type; // QUERY_NODE_TEMP_TABLE
+  SNode* pSubquery;
+} STempTableNode;
+
+typedef enum EJoinType {
+  JOIN_TYPE_INNER = 1
+} EJoinType;
+
+typedef struct SJoinTableNode {
+  STableNode type; // QUERY_NODE_JOIN_TABLE
+  EJoinType joinType;
+  SNode* pLeft;
+  SNode* pRight;
+  SNode* pOnCond;
+} SJoinTableNode;
+
+typedef enum EGroupingSetType {
+  GP_TYPE_NORMAL = 1
+} EGroupingSetType;
+
+typedef struct SGroupingSetNode {
+  ENodeType type; // QUERY_NODE_GROUPING_SET
+  EGroupingSetType groupingSetType;
+  SArray* pParameterList; 
+} SGroupingSetNode;
+
+typedef enum EOrder {
+  ORDER_ASC = 1,
+  ORDER_DESC
+} EOrder;
+
+typedef enum ENullOrder {
+  NULL_ORDER_FIRST = 1,
+  NULL_ORDER_LAST
+} ENullOrder;
+
+typedef struct SOrderByExprNode {
+  ENodeType type; // QUERY_NODE_ORDER_BY_EXPR
+  SNode* pExpr;
+  EOrder order;
+  ENullOrder nullOrder;
+} SOrderByExprNode;
+
+typedef struct SLimitInfo {
+  uint64_t limit;
+  uint64_t offset;
+} SLimitInfo;
+
+typedef struct SStateWindowNode {
+  ENodeType type; // QUERY_NODE_STATE_WINDOW
+  SNode* pCol;
+} SStateWindowNode;
+
+typedef struct SSessionWindowNode {
+  ENodeType type; // QUERY_NODE_SESSION_WINDOW
+  int64_t gap;             // gap between two session window(in microseconds)
+  SNode* pCol;
+} SSessionWindowNode;
+
+typedef struct SIntervalWindowNode {
+  ENodeType type; // QUERY_NODE_INTERVAL_WINDOW
+  int64_t interval;
+  int64_t sliding;
+  int64_t offset;
+} SIntervalWindowNode;
+
+typedef struct SSelectStmt {
+  ENodeType type; // QUERY_NODE_SELECT_STMT
+  bool isDistinct;
+  SArray* pProjectionList; // SNode
+  SNode* pFromTable;
+  SNode* pWhereCond;
+  SArray* pPartitionByList; // SNode
+  SNode* pWindowClause;
+  SArray* pGroupByList; // SGroupingSetNode
+  SArray* pOrderByList; // SOrderByExprNode
+  SLimitInfo limit;
+  SLimitInfo slimit;
+} SSelectStmt;
+
+typedef enum ESetOperatorType {
+  SET_OP_TYPE_UNION_ALL = 1
+} ESetOperatorType;
+
+typedef struct SSetOperator {
+  ENodeType type; // QUERY_NODE_SET_OPERATOR
+  ESetOperatorType opType;
+  SNode* pLeft;
+  SNode* pRight;
+} SSetOperator;
+
+typedef bool (*FQueryNodeWalker)(SNode* pNode, void* pContext);
+
+bool nodeArrayWalker(SArray* pArray, FQueryNodeWalker walker, void* pContext);
+bool nodeTreeWalker(SNode* pNode, FQueryNodeWalker walker, void* pContext);
+
+bool stmtWalker(SNode* pNode, FQueryNodeWalker walker, void* pContext);
+
+bool nodeEqual(const SNode* a, const SNode* b);
+
+void cloneNode(const SNode* pNode);
+
+int32_t nodeToString(const SNode* pNode, char** pStr, int32_t* pLen);
+int32_t stringToNode(const char* pStr, SNode** pNode);
+
+bool isTimeorderQuery(const SNode* pQuery);
+bool isTimelineQuery(const SNode* pQuery);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /*_TD_NODES_H_*/
diff --git a/source/CMakeLists.txt b/source/CMakeLists.txt
index 2833b329a751286e2f52799118b5147cc4d41b5e..fbf045b99c84830e7ab8204a4901b7fc3b143f2b 100644
--- a/source/CMakeLists.txt
+++ b/source/CMakeLists.txt
@@ -3,4 +3,5 @@ add_subdirectory(util)
 add_subdirectory(common)
 add_subdirectory(libs)
 add_subdirectory(client)
-add_subdirectory(dnode)
\ No newline at end of file
+add_subdirectory(dnode)
+add_subdirectory(nodes)
\ No newline at end of file
diff --git a/source/dnode/mnode/impl/src/mndSubscribe.c b/source/dnode/mnode/impl/src/mndSubscribe.c
index 7b95e932574e48c734311d34520490644e4b39c2..4158d7e7c73bf46e01a01e08418592d12dad1c2e 100644
--- a/source/dnode/mnode/impl/src/mndSubscribe.c
+++ b/source/dnode/mnode/impl/src/mndSubscribe.c
@@ -55,8 +55,6 @@ int32_t mndInitSubscribe(SMnode *pMnode) {
                      .deleteFp = (SdbDeleteFp)mndSubActionDelete};
 
   mndSetMsgHandle(pMnode, TDMT_MND_SUBSCRIBE, mndProcessSubscribeReq);
-  /*mndSetMsgHandle(pMnode, TDMT_MND_SUBSCRIBE_RSP, mndProcessSubscribeRsp);*/
-  /*mndSetMsgHandle(pMnode, TDMT_VND_SUBSCRIBE, mndProcessSubscribeInternalReq);*/
   mndSetMsgHandle(pMnode, TDMT_VND_SUBSCRIBE_RSP, mndProcessSubscribeInternalRsp);
   mndSetMsgHandle(pMnode, TDMT_MND_MQ_TIMER, mndProcessMqTimerMsg);
   return sdbSetTable(pMnode->pSdb, table);
@@ -95,7 +93,7 @@ static int32_t mndProcessMqTimerMsg(SMnodeMsg *pMsg) {
         SMqConsumerEp *pCEp = taosArrayPop(pSub->unassignedVg);
         pCEp->consumerId = consumerId;
         taosArrayPush(pSub->assigned, pCEp);
-        pSub->nextConsumerIdx++;
+        pSub->nextConsumerIdx = (pSub->nextConsumerIdx + 1) % taosArrayGetSize(pSub->availConsumer);
 
         // build msg
         SMqSetCVgReq req = {
@@ -464,7 +462,7 @@ static int32_t mndProcessSubscribeReq(SMnodeMsg *pMsg) {
       }
       taosArrayPush(pSub->availConsumer, &consumerId);
 
-      //TODO: no need
+      // TODO: no need
       SMqConsumerTopic *pConsumerTopic = tNewConsumerTopic(consumerId, pTopic, pSub);
       taosArrayPush(pConsumer->topics, pConsumerTopic);
 
@@ -542,7 +540,10 @@ static int32_t mndProcessSubscribeReq(SMnodeMsg *pMsg) {
   return 0;
 }
 
-static int32_t mndProcessSubscribeInternalRsp(SMnodeMsg *pMsg) { return 0; }
+static int32_t mndProcessSubscribeInternalRsp(SMnodeMsg *pRsp) {
+  mndTransProcessRsp(pRsp);
+  return 0;
+}
 
 static int32_t mndProcessConsumerMetaMsg(SMnodeMsg *pMsg) {
   SMnode        *pMnode = pMsg->pMnode;
diff --git a/source/dnode/vnode/CMakeLists.txt b/source/dnode/vnode/CMakeLists.txt
index 9dc4bb18737d87860575a7e8d79de42ec8689cce..75734d2d29a0794c7c38284dc9d7cbf0b94bbf56 100644
--- a/source/dnode/vnode/CMakeLists.txt
+++ b/source/dnode/vnode/CMakeLists.txt
@@ -25,6 +25,7 @@ target_link_libraries(
     PUBLIC bdb
     PUBLIC tfs
     PUBLIC wal
+    PUBLIC scheduler
     PUBLIC qworker
 )
 
diff --git a/source/dnode/vnode/inc/tq.h b/source/dnode/vnode/inc/tq.h
index 8089826a80ed945b1716cb19b8489d58c4fc366d..e394297ab8db0021193bbdb856397aa21bc0a634 100644
--- a/source/dnode/vnode/inc/tq.h
+++ b/source/dnode/vnode/inc/tq.h
@@ -18,14 +18,16 @@
 
 #include "common.h"
 #include "mallocator.h"
+#include "meta.h"
 #include "os.h"
+#include "scheduler.h"
 #include "taoserror.h"
-#include "tmsg.h"
 #include "tlist.h"
+#include "tmsg.h"
 #include "trpc.h"
 #include "ttimer.h"
 #include "tutil.h"
-#include "meta.h"
+#include "wal.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -150,31 +152,52 @@ typedef struct STqListHandle {
 } STqList;
 
 typedef struct STqGroup {
-  int64_t clientId;
-  int64_t cgId;
-  void*   ahandle;
-  int32_t topicNum;
+  int64_t      clientId;
+  int64_t      cgId;
+  void*        ahandle;
+  int32_t      topicNum;
   STqList*     head;
   SList*       topicList;  // SList<STqTopic>
   STqRspHandle rspHandle;
 } STqGroup;
 
+typedef struct STqTaskItem {
+  int8_t        status;
+  int64_t       offset;
+  void*         dst;
+  SSubQueryMsg* pMsg;
+} STqTaskItem;
+
+// new version
+typedef struct STqBuffer {
+  int64_t     firstOffset;
+  int64_t     lastOffset;
+  STqTaskItem output[TQ_BUFFER_SIZE];
+} STqBuffer;
+
+typedef struct STqTopicHandle {
+  char            topicName[TSDB_TOPIC_FNAME_LEN];
+  char            cgroup[TSDB_TOPIC_FNAME_LEN];
+  char*           sql;
+  char*           logicalPlan;
+  char*           physicalPlan;
+  int64_t         committedOffset;
+  int64_t         currentOffset;
+  STqBuffer       buffer;
+  SWalReadHandle* pReadhandle;
+} STqTopicHandle;
+
+typedef struct STqConsumerHandle {
+  int64_t consumerId;
+  int64_t epoch;
+  SArray* topics;  // SArray<STqClientTopic>
+} STqConsumerHandle;
+
 typedef struct STqQueryMsg {
   STqMsgItem*         item;
   struct STqQueryMsg* next;
 } STqQueryMsg;
 
-typedef struct STqLogHandle {
-  void* logHandle;
-  void* (*openLogReader)(void* logHandle);
-  void (*closeLogReader)(void* logReader);
-  int32_t (*logRead)(void* logReader, void** data, int64_t ver);
-
-  int64_t (*logGetFirstVer)(void* logHandle);
-  int64_t (*logGetSnapshotVer)(void* logHandle);
-  int64_t (*logGetLastVer)(void* logHandle);
-} STqLogHandle;
-
 typedef struct STqCfg {
   // TODO
 } STqCfg;
@@ -253,7 +276,7 @@ typedef struct STqMetaStore {
   // a table head
   STqMetaList* unpersistHead;
   // topics that are not connectted
-  STqMetaList*   unconnectTopic;
+  STqMetaList* unconnectTopic;
 
   // TODO:temporaral use, to be replaced by unified tfile
   int fileFd;
@@ -272,9 +295,9 @@ typedef struct STQ {
   // the handle of meta kvstore
   char*         path;
   STqCfg*       tqConfig;
-  STqLogHandle* tqLogHandle;
   STqMemRef     tqMemRef;
   STqMetaStore* tqMeta;
+  SWal        * pWal;
 } STQ;
 
 typedef struct STqMgmt {
@@ -289,51 +312,41 @@ int  tqInit();
 void tqCleanUp();
 
 // open in each vnode
-STQ* tqOpen(const char* path, STqCfg* tqConfig, STqLogHandle* tqLogHandle, SMemAllocatorFactory* allocFac);
+STQ* tqOpen(const char* path, SWal* pWal, STqCfg* tqConfig, SMemAllocatorFactory* allocFac);
 void tqClose(STQ*);
 
 // void* will be replace by a msg type
 int tqPushMsg(STQ*, void* msg, int64_t version);
 int tqCommit(STQ*);
-int tqConsume(STQ*, SRpcMsg* pReq, SRpcMsg** pRsp);
 
+#if 0
+int tqConsume(STQ*, SRpcMsg* pReq, SRpcMsg** pRsp);
 int tqSetCursor(STQ*, STqSetCurReq* pMsg);
 int tqBufferSetOffset(STqTopic*, int64_t offset);
-
 STqTopic* tqFindTopic(STqGroup*, int64_t topicId);
-
 STqGroup* tqGetGroup(STQ*, int64_t clientId);
-
 STqGroup* tqOpenGroup(STQ*, int64_t topicId, int64_t cgId, int64_t cId);
 int       tqCloseGroup(STQ*, int64_t topicId, int64_t cgId, int64_t cId);
 int       tqRegisterContext(STqGroup*, void* ahandle);
 int       tqSendLaunchQuery(STqMsgItem*, int64_t offset);
+#endif
 
-int tqSerializeGroup(const STqGroup*, STqSerializedHead**);
-
-const void* tqDeserializeGroup(const STqSerializedHead*, STqGroup**);
-
-static int tqQueryExecuting(int32_t status) { return status; }
+int32_t tqProcessConsume(STQ* pTq, SRpcMsg* pMsg, SRpcMsg** ppRsp);
 
 typedef struct STqReadHandle {
-  int64_t ver;
-  SSubmitMsg* pMsg;
-  SSubmitBlk* pBlock;
+  int64_t        ver;
+  SSubmitMsg*    pMsg;
+  SSubmitBlk*    pBlock;
   SSubmitMsgIter msgIter;
   SSubmitBlkIter blkIter;
-  SMeta* pMeta;
+  SMeta*         pMeta;
 } STqReadHandle;
 
-typedef struct SSubmitBlkScanInfo {
-  
-} SSubmitBlkScanInfo;
-
-STqReadHandle* tqInitSubmitMsgScanner(SMeta* pMeta, SSubmitMsg *pMsg);
-bool tqNextDataBlock(STqReadHandle* pHandle);
-int tqRetrieveDataBlockInfo(STqReadHandle* pHandle, SDataBlockInfo *pBlockInfo);
-//return SArray<SColumnInfoData>
-SArray *tqRetrieveDataBlock(STqReadHandle* pHandle, SArray* pColumnIdList);
-//int tqLoadDataBlock(SExecTaskInfo* pTaskInfo, SSubmitBlkScanInfo* pSubmitBlkScanInfo, SSDataBlock* pBlock, uint32_t status);
+STqReadHandle* tqInitSubmitMsgScanner(SMeta* pMeta, SSubmitMsg* pMsg);
+bool           tqNextDataBlock(STqReadHandle* pHandle);
+int            tqRetrieveDataBlockInfo(STqReadHandle* pHandle, SDataBlockInfo* pBlockInfo);
+// return SArray<SColumnInfoData>
+SArray* tqRetrieveDataBlock(STqReadHandle* pHandle, SArray* pColumnIdList);
 
 #ifdef __cplusplus
 }
diff --git a/source/dnode/vnode/src/inc/tqInt.h b/source/dnode/vnode/src/inc/tqInt.h
index 107f5d51038bf5577079c49c40951700c778602a..b4e1f573840b754e819577e85abe9660c47dcbeb 100644
--- a/source/dnode/vnode/src/inc/tqInt.h
+++ b/source/dnode/vnode/src/inc/tqInt.h
@@ -43,6 +43,9 @@ extern int32_t tqDebugFlag;
 // delete persistent storage for meta info
 // int tqDropTCGroup(STQ*, const char* topic, int cgId);
 
+int tqSerializeGroup(const STqGroup*, STqSerializedHead**);
+const void* tqDeserializeGroup(const STqSerializedHead* pHead, STqGroup** ppGroup);
+static int FORCE_INLINE tqQueryExecuting(int32_t status) { return status; }
 #ifdef __cplusplus
 }
 #endif
diff --git a/source/dnode/vnode/src/inc/vnd.h b/source/dnode/vnode/src/inc/vnd.h
index 6b99b71b629c106ba3b129a8b185137d4da15dc3..be32ed682984a25289f00fbdeabb923cea130966 100644
--- a/source/dnode/vnode/src/inc/vnd.h
+++ b/source/dnode/vnode/src/inc/vnd.h
@@ -177,4 +177,4 @@ bool            vmaIsFull(SVMemAllocator* pVMA);
 }
 #endif
 
-#endif /*_TD_VNODE_DEF_H_*/
\ No newline at end of file
+#endif /*_TD_VNODE_DEF_H_*/
diff --git a/source/dnode/vnode/src/tq/tq.c b/source/dnode/vnode/src/tq/tq.c
index a5be0ec29a97934c14612b3b9f187b58f3753ecb..15c797125250c2a4ff328e9ea52459f6daaaf10b 100644
--- a/source/dnode/vnode/src/tq/tq.c
+++ b/source/dnode/vnode/src/tq/tq.c
@@ -37,7 +37,7 @@ const void* tqDeserializeItem(const void* pBytes, STqMsgItem* pItem);
 
 int tqInit() {
   int8_t old = atomic_val_compare_exchange_8(&tqMgmt.inited, 0, 1);
-  if(old == 1) return 0;
+  if (old == 1) return 0;
 
   tqMgmt.timer = taosTmrInit(0, 0, 0, "TQ");
   return 0;
@@ -45,12 +45,12 @@ int tqInit() {
 
 void tqCleanUp() {
   int8_t old = atomic_val_compare_exchange_8(&tqMgmt.inited, 1, 0);
-  if(old == 0) return;
+  if (old == 0) return;
   taosTmrStop(tqMgmt.timer);
   taosTmrCleanUp(tqMgmt.timer);
 }
 
-STQ* tqOpen(const char* path, STqCfg* tqConfig, STqLogHandle* tqLogHandle, SMemAllocatorFactory* allocFac) {
+STQ* tqOpen(const char* path, SWal* pWal, STqCfg* tqConfig, SMemAllocatorFactory* allocFac) {
   STQ* pTq = malloc(sizeof(STQ));
   if (pTq == NULL) {
     terrno = TSDB_CODE_TQ_OUT_OF_MEMORY;
@@ -58,7 +58,6 @@ STQ* tqOpen(const char* path, STqCfg* tqConfig, STqLogHandle* tqLogHandle, SMemA
   }
   pTq->path = strdup(path);
   pTq->tqConfig = tqConfig;
-  pTq->tqLogHandle = tqLogHandle;
 #if 0
   pTq->tqMemRef.pAllocatorFactory = allocFac;
   pTq->tqMemRef.pAllocator = allocFac->create(allocFac);
@@ -150,7 +149,7 @@ int tqCreateGroup(STQ* pTq, int64_t topicId, int64_t cgId, int64_t cId, STqGroup
   memset(pGroup, 0, sizeof(STqGroup));
 
   pGroup->topicList = tdListNew(sizeof(STqTopic));
-  if(pGroup->topicList == NULL) {
+  if (pGroup->topicList == NULL) {
     free(pGroup);
     return -1;
   }
@@ -190,7 +189,7 @@ static int tqFetch(STqGroup* pGroup, STqConsumeRsp** pRsp) {
   int      totSize = 0;
   int      numOfMsgs = 0;
   // TODO: make it a macro
-  int   sizeLimit = 4 * 1024;
+  int sizeLimit = 4 * 1024;
 
   void* ptr = realloc(*pRsp, sizeof(STqConsumeRsp) + sizeLimit);
   if (ptr == NULL) {
@@ -329,9 +328,9 @@ int tqProcessCMsg(STQ* pTq, STqConsumeReq* pMsg, STqRspHandle* pRsp) {
 }
 
 int tqConsume(STQ* pTq, SRpcMsg* pReq, SRpcMsg** pRsp) {
-  STqConsumeReq *pMsg = pReq->pCont;
-  int64_t   clientId = pMsg->head.clientId;
-  STqGroup* pGroup = tqGetGroup(pTq, clientId);
+  STqConsumeReq* pMsg = pReq->pCont;
+  int64_t        clientId = pMsg->head.clientId;
+  STqGroup*      pGroup = tqGetGroup(pTq, clientId);
   if (pGroup == NULL) {
     terrno = TSDB_CODE_TQ_GROUP_NOT_SET;
     return -1;
@@ -343,9 +342,8 @@ int tqConsume(STQ* pTq, SRpcMsg* pReq, SRpcMsg** pRsp) {
   int numOfMsgs = 0;
   int sizeLimit = 4096;
 
-
-  STqConsumeRsp *pCsmRsp = (*pRsp)->pCont;
-  void* ptr = realloc((*pRsp)->pCont, sizeof(STqConsumeRsp) + sizeLimit);
+  STqConsumeRsp* pCsmRsp = (*pRsp)->pCont;
+  void*          ptr = realloc((*pRsp)->pCont, sizeof(STqConsumeRsp) + sizeLimit);
   if (ptr == NULL) {
     terrno = TSDB_CODE_TQ_OUT_OF_MEMORY;
     return -1;
@@ -356,16 +354,16 @@ int tqConsume(STQ* pTq, SRpcMsg* pReq, SRpcMsg** pRsp) {
   tdListInitIter(topicList, &iter, TD_LIST_FORWARD);
 
   STqMsgContent* buffer = NULL;
-  SArray* pArray = taosArrayInit(0, sizeof(void*));
+  SArray*        pArray = taosArrayInit(0, sizeof(void*));
 
-  SListNode *pn;
-  while((pn = tdListNext(&iter)) != NULL) {
-    STqTopic* pTopic = *(STqTopic**)pn->data;
-    int idx = pTopic->floatingCursor % TQ_BUFFER_SIZE;
+  SListNode* pn;
+  while ((pn = tdListNext(&iter)) != NULL) {
+    STqTopic*   pTopic = *(STqTopic**)pn->data;
+    int         idx = pTopic->floatingCursor % TQ_BUFFER_SIZE;
     STqMsgItem* pItem = &pTopic->buffer[idx];
     if (pItem->content != NULL && pItem->offset == pTopic->floatingCursor) {
-      if(pItem->status == TQ_ITEM_READY) {
-        //if has data
+      if (pItem->status == TQ_ITEM_READY) {
+        // if has data
         totSize += pTopic->buffer[idx].size;
         if (totSize > sizeLimit) {
           void* ptr = realloc((*pRsp)->pCont, sizeof(STqConsumeRsp) + totSize);
@@ -388,13 +386,13 @@ int tqConsume(STQ* pTq, SRpcMsg* pReq, SRpcMsg** pRsp) {
         if (totSize > sizeLimit) {
           break;
         }
-      } else if(pItem->status == TQ_ITEM_PROCESS) {
-        //if not have data but in process
+      } else if (pItem->status == TQ_ITEM_PROCESS) {
+        // if not have data but in process
 
-      } else if(pItem->status == TQ_ITEM_EMPTY){
-        //if not have data and not in process
+      } else if (pItem->status == TQ_ITEM_EMPTY) {
+        // if not have data and not in process
         int32_t old = atomic_val_compare_exchange_32(&pItem->status, TQ_ITEM_EMPTY, TQ_ITEM_PROCESS);
-        if(old != TQ_ITEM_EMPTY) {
+        if (old != TQ_ITEM_EMPTY) {
           continue;
         }
         pItem->offset = pTopic->floatingCursor;
@@ -416,22 +414,22 @@ int tqConsume(STQ* pTq, SRpcMsg* pReq, SRpcMsg** pRsp) {
   }
 
   // fetched a num of msgs, rpc response
-  for(int i = 0; i < pArray->size; i++) {
+  for (int i = 0; i < pArray->size; i++) {
     STqMsgItem* pItem = taosArrayGet(pArray, i);
 
-    //read from wal
+    // read from wal
     void* raw = NULL;
     /*int code = pTq->tqLogReader->logRead(, &raw, pItem->offset);*/
-    int code = pTq->tqLogHandle->logRead(pItem->pTopic->logReader, &raw, pItem->offset);
-    if(code < 0) {
-      //TODO: error
-    }
-    //get msgType
-    //if submitblk
+    /*int code = pTq->tqLogHandle->logRead(pItem->pTopic->logReader, &raw, pItem->offset);*/
+    /*if (code < 0) {*/
+      // TODO: error
+    /*}*/
+    // get msgType
+    // if submitblk
     pItem->executor->assign(pItem->executor->runtimeEnv, raw);
     SSDataBlock* content = pItem->executor->exec(pItem->executor->runtimeEnv);
     pItem->content = content;
-    //if other type, send just put into buffer
+    // if other type, send just put into buffer
     /*pItem->content = raw;*/
 
     int32_t old = atomic_val_compare_exchange_32(&pItem->status, TQ_ITEM_PROCESS, TQ_ITEM_READY);
@@ -608,7 +606,48 @@ int tqItemSSize() {
   return 0;
 }
 
-STqReadHandle* tqInitSubmitMsgScanner(SMeta* pMeta, SSubmitMsg *pMsg) {
+int32_t tqProcessConsume(STQ* pTq, SRpcMsg* pMsg, SRpcMsg** ppRsp) {
+  SMqCVConsumeReq* pReq = pMsg->pCont;
+  int64_t          reqId = pReq->reqId;
+  int64_t          consumerId = pReq->consumerId;
+  int64_t          offset = pReq->offset;
+  int64_t          blockingTime = pReq->blockingTime;
+
+  STqConsumerHandle* pConsumer = tqHandleGet(pTq->tqMeta, consumerId);
+  int sz = taosArrayGetSize(pConsumer->topics);
+
+  for (int i = 0 ; i < sz; i++) {
+    STqTopicHandle *pHandle = taosArrayGet(pConsumer->topics, i);
+
+    int8_t           pos = offset % TQ_BUFFER_SIZE;
+    int8_t           old = atomic_val_compare_exchange_8(&pHandle->buffer.output[pos].status, 0, 1);
+    if (old == 1) {
+      // do nothing
+    }
+    if (walReadWithHandle(pHandle->pReadhandle, offset) < 0) {
+      // TODO
+    }
+    SWalHead* pHead = pHandle->pReadhandle->pHead;
+    while (pHead->head.msgType != TDMT_VND_SUBMIT) {
+      // read until find TDMT_VND_SUBMIT
+    }
+    SSubmitMsg* pCont = (SSubmitMsg*)&pHead->head.body;
+
+    SSubQueryMsg* pQueryMsg = pHandle->buffer.output[pos].pMsg;
+
+    void* outputData;
+    atomic_store_8(&pHandle->buffer.output[pos].status, 1);
+
+    // put output into rsp
+  }
+
+  // launch query
+  // get result
+  SMqCvConsumeRsp* pRsp;
+  return 0;
+}
+
+STqReadHandle* tqInitSubmitMsgScanner(SMeta* pMeta, SSubmitMsg* pMsg) {
   STqReadHandle* pReadHandle = malloc(sizeof(STqReadHandle));
   if (pReadHandle == NULL) {
     return NULL;
@@ -621,39 +660,39 @@ STqReadHandle* tqInitSubmitMsgScanner(SMeta* pMeta, SSubmitMsg *pMsg) {
 }
 
 bool tqNextDataBlock(STqReadHandle* pHandle) {
-  if(tGetSubmitMsgNext(&pHandle->msgIter, &pHandle->pBlock) < 0) {
+  if (tGetSubmitMsgNext(&pHandle->msgIter, &pHandle->pBlock) < 0) {
     return false;
   }
   return true;
 }
 
 int tqRetrieveDataBlockInfo(STqReadHandle* pHandle, SDataBlockInfo* pBlockInfo) {
-  SMemRow row;
-  int32_t sversion = pHandle->pBlock->sversion;
+  SMemRow         row;
+  int32_t         sversion = pHandle->pBlock->sversion;
   SSchemaWrapper* pSchema = metaGetTableSchema(pHandle->pMeta, pHandle->pBlock->uid, sversion, false);
   pBlockInfo->numOfCols = pSchema->nCols;
   pBlockInfo->rows = pHandle->pBlock->numOfRows;
   pBlockInfo->uid = pHandle->pBlock->uid;
-  //TODO: filter out unused column
+  // TODO: filter out unused column
   return 0;
 }
-SArray *tqRetrieveDataBlock(STqReadHandle* pHandle, SArray* pColumnIdList) {
-  int32_t sversion = pHandle->pBlock->sversion;
+SArray* tqRetrieveDataBlock(STqReadHandle* pHandle, SArray* pColumnIdList) {
+  int32_t         sversion = pHandle->pBlock->sversion;
   SSchemaWrapper* pSchemaWrapper = metaGetTableSchema(pHandle->pMeta, pHandle->pBlock->uid, sversion, true);
-  STSchema* pTschema = metaGetTbTSchema(pHandle->pMeta, pHandle->pBlock->uid, sversion);
-  SArray *pArray = taosArrayInit(pSchemaWrapper->nCols, sizeof(SColumnInfoData));
+  STSchema*       pTschema = metaGetTbTSchema(pHandle->pMeta, pHandle->pBlock->uid, sversion);
+  SArray*         pArray = taosArrayInit(pSchemaWrapper->nCols, sizeof(SColumnInfoData));
   if (pArray == NULL) {
     return NULL;
   }
   SColumnInfoData colInfo;
-  int sz = pSchemaWrapper->nCols * pSchemaWrapper->pSchema->bytes;
+  int             sz = pSchemaWrapper->nCols * pSchemaWrapper->pSchema->bytes;
   colInfo.pData = malloc(sz);
   if (colInfo.pData == NULL) {
     return NULL;
   }
 
   for (int i = 0; i < pTschema->numOfCols; i++) {
-    //TODO: filter out unused column
+    // TODO: filter out unused column
     taosArrayPush(pColumnIdList, &(schemaColAt(pTschema, i)->colId));
   }
 
@@ -661,16 +700,17 @@ SArray *tqRetrieveDataBlock(STqReadHandle* pHandle, SArray* pColumnIdList) {
   int32_t kvIdx;
   while ((row = tGetSubmitBlkNext(&pHandle->blkIter)) != NULL) {
     for (int i = 0; i < pTschema->numOfCols && kvIdx < pTschema->numOfCols; i++) {
-    //TODO: filter out unused column
-      STColumn *pCol = schemaColAt(pTschema, i);
+      // TODO: filter out unused column
+      STColumn* pCol = schemaColAt(pTschema, i);
       void* val = tdGetMemRowDataOfColEx(row, pCol->colId, pCol->type, TD_DATA_ROW_HEAD_SIZE + pCol->offset, &kvIdx);
-      //TODO: handle varlen
+      // TODO: handle varlen
       memcpy(POINTER_SHIFT(colInfo.pData, pCol->offset), val, pCol->bytes);
     }
   }
   taosArrayPush(pArray, &colInfo);
   return pArray;
 }
-/*int tqLoadDataBlock(SExecTaskInfo* pTaskInfo, SSubmitBlkScanInfo* pSubmitBlkScanInfo, SSDataBlock* pBlock, uint32_t status) {*/
-  /*return 0;*/
+/*int tqLoadDataBlock(SExecTaskInfo* pTaskInfo, SSubmitBlkScanInfo* pSubmitBlkScanInfo, SSDataBlock* pBlock, uint32_t
+ * status) {*/
+/*return 0;*/
 /*}*/
diff --git a/source/dnode/vnode/src/vnd/vnodeMain.c b/source/dnode/vnode/src/vnd/vnodeMain.c
index 76b7ccf0d9384f723501cbb640e8a36a3543d523..c4bbd93eda7e3a28835e5536028139a636f1f93d 100644
--- a/source/dnode/vnode/src/vnd/vnodeMain.c
+++ b/source/dnode/vnode/src/vnd/vnodeMain.c
@@ -117,14 +117,6 @@ static int vnodeOpenImpl(SVnode *pVnode) {
     return -1;
   }
 
-  // TODO: Open TQ
-  sprintf(dir, "%s/tq", pVnode->path);
-  pVnode->pTq = tqOpen(dir, &(pVnode->config.tqCfg), NULL, vBufPoolGetMAF(pVnode));
-  if (pVnode->pTq == NULL) {
-    // TODO: handle error
-    return -1;
-  }
-
   // Open WAL
   sprintf(dir, "%s/wal", pVnode->path);
   pVnode->pWal = walOpen(dir, &(pVnode->config.walCfg));
@@ -133,6 +125,14 @@ static int vnodeOpenImpl(SVnode *pVnode) {
     return -1;
   }
 
+  // Open TQ
+  sprintf(dir, "%s/tq", pVnode->path);
+  pVnode->pTq = tqOpen(dir, pVnode->pWal, &(pVnode->config.tqCfg), vBufPoolGetMAF(pVnode));
+  if (pVnode->pTq == NULL) {
+    // TODO: handle error
+    return -1;
+  }
+
   // Open Query
   if (vnodeQueryOpen(pVnode)) {
     return -1;
@@ -151,4 +151,4 @@ static void vnodeCloseImpl(SVnode *pVnode) {
     tqClose(pVnode->pTq);
     walClose(pVnode->pWal);
   }
-}
\ No newline at end of file
+}
diff --git a/source/dnode/vnode/src/vnd/vnodeQuery.c b/source/dnode/vnode/src/vnd/vnodeQuery.c
index 2e9c77c59be6cb36aa29dc998dc5fed4e0be8e40..96791488fa2182a7b2c95505d4a2eb7ac456d2b9 100644
--- a/source/dnode/vnode/src/vnd/vnodeQuery.c
+++ b/source/dnode/vnode/src/vnd/vnodeQuery.c
@@ -57,6 +57,8 @@ int vnodeProcessFetchReq(SVnode *pVnode, SRpcMsg *pMsg, SRpcMsg **pRsp) {
       //      return qWorkerProcessShowFetchMsg(pVnode->pMeta, pVnode->pQuery, pMsg);
     case TDMT_VND_TABLE_META:
       return vnodeGetTableMeta(pVnode, pMsg, pRsp);
+    case TDMT_VND_CONSUME:
+      return tqProcessConsume(pVnode->pTq, pMsg, pRsp);
     default:
       vError("unknown msg type:%d in fetch queue", pMsg->msgType);
       return TSDB_CODE_VND_APP_ERROR;
diff --git a/source/dnode/vnode/src/vnd/vnodeWrite.c b/source/dnode/vnode/src/vnd/vnodeWrite.c
index ea69f4c870f7a65835d94bd5132a28489105ff83..6e2d438970f00fa3c87d8ebadece933ee4cbb9c8 100644
--- a/source/dnode/vnode/src/vnd/vnodeWrite.c
+++ b/source/dnode/vnode/src/vnd/vnodeWrite.c
@@ -14,6 +14,7 @@
  */
 
 #include "vnd.h"
+#include "tq.h"
 
 int vnodeProcessNoWalWMsgs(SVnode *pVnode, SRpcMsg *pMsg) {
   switch (pMsg->msgType) {
@@ -109,11 +110,40 @@ int vnodeApplyWMsg(SVnode *pVnode, SRpcMsg *pMsg, SRpcMsg **pRsp) {
       }
       break;
     case TDMT_VND_MQ_SET_CONN: {
+      //TODO: wrap in a function
       char* reqStr = ptr;
       SMqSetCVgReq req;
-      /*tDecodeSMqSetCVgReq(reqStr, &req);*/
-      // create topic if not exist
+      tDecodeSMqSetCVgReq(reqStr, &req);
+      STqConsumerHandle* pConsumer = calloc(sizeof(STqConsumerHandle), 1);
+      
+      STqTopicHandle* pTopic = calloc(sizeof(STqTopicHandle), 1);
+      if (pTopic == NULL) {
+        // TODO: handle error
+      }
+      strcpy(pTopic->topicName, req.topicName); 
+      strcpy(pTopic->cgroup, req.cGroup); 
+      strcpy(pTopic->sql, req.sql);
+      strcpy(pTopic->logicalPlan, req.logicalPlan);
+      strcpy(pTopic->physicalPlan, req.physicalPlan);
+      SArray *pArray;
+      //TODO: deserialize to SQueryDag
+      SQueryDag *pDag;
       // convert to task
+      if (schedulerConvertDagToTaskList(pDag, &pArray) < 0) {
+        // TODO: handle error
+      }
+      ASSERT(taosArrayGetSize(pArray) == 0);
+      STaskInfo *pInfo = taosArrayGet(pArray, 0);
+      SArray* pTasks;
+      schedulerCopyTask(pInfo, &pTasks, TQ_BUFFER_SIZE);
+      pTopic->buffer.firstOffset = -1;
+      pTopic->buffer.lastOffset = -1;
+      for (int i = 0; i < TQ_BUFFER_SIZE; i++) {
+        SSubQueryMsg* pMsg = taosArrayGet(pTasks, i);
+        pTopic->buffer.output[i].pMsg = pMsg;
+        pTopic->buffer.output[i].status = 0;
+      }
+      pTopic->pReadhandle = walOpenReadHandle(pVnode->pTq->pWal);
       // write mq meta
     }
       break;
diff --git a/source/libs/function/CMakeLists.txt b/source/libs/function/CMakeLists.txt
index a4aa7025e47837d2b886f4b9cb912e165f7fb1e2..9f700dbb3ccb3ab1c475789ab53b10fb0fa6bc4c 100644
--- a/source/libs/function/CMakeLists.txt
+++ b/source/libs/function/CMakeLists.txt
@@ -8,5 +8,5 @@ target_include_directories(
 
 target_link_libraries(
     function
-    PRIVATE os util common
+    PRIVATE os util common nodes
 )
\ No newline at end of file
diff --git a/source/libs/function/inc/functionMgtInt.h b/source/libs/function/inc/functionMgtInt.h
new file mode 100644
index 0000000000000000000000000000000000000000..9b9d82f0e18504d714aeefc201b366fd7b27aa4d
--- /dev/null
+++ b/source/libs/function/inc/functionMgtInt.h
@@ -0,0 +1,76 @@
+/*
+ * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
+ *
+ * This program is free software: you can use, redistribute, and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3
+ * or later ("AGPL"), as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _TD_FUNCTION_MGT_INT_H_
+#define _TD_FUNCTION_MGT_INT_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "functionMgt.h"
+
+#define FUNC_MGT_DATA_TYPE_MASK(n)    (1 << n)
+
+#define FUNC_MGT_DATA_TYPE_NULL       0
+#define FUNC_MGT_DATA_TYPE_BOOL       FUNC_MGT_DATA_TYPE_MASK(0)
+#define FUNC_MGT_DATA_TYPE_TINYINT    FUNC_MGT_DATA_TYPE_MASK(1)
+#define FUNC_MGT_DATA_TYPE_SMALLINT   FUNC_MGT_DATA_TYPE_MASK(2)
+#define FUNC_MGT_DATA_TYPE_INT        FUNC_MGT_DATA_TYPE_MASK(3)
+#define FUNC_MGT_DATA_TYPE_BIGINT     FUNC_MGT_DATA_TYPE_MASK(4)
+#define FUNC_MGT_DATA_TYPE_FLOAT      FUNC_MGT_DATA_TYPE_MASK(5)
+#define FUNC_MGT_DATA_TYPE_DOUBLE     FUNC_MGT_DATA_TYPE_MASK(6)
+#define FUNC_MGT_DATA_TYPE_BINARY     FUNC_MGT_DATA_TYPE_MASK(7)
+#define FUNC_MGT_DATA_TYPE_TIMESTAMP  FUNC_MGT_DATA_TYPE_MASK(8)
+#define FUNC_MGT_DATA_TYPE_NCHAR      FUNC_MGT_DATA_TYPE_MASK(9)
+#define FUNC_MGT_DATA_TYPE_UTINYINT   FUNC_MGT_DATA_TYPE_MASK(10)
+#define FUNC_MGT_DATA_TYPE_USMALLINT  FUNC_MGT_DATA_TYPE_MASK(11)
+#define FUNC_MGT_DATA_TYPE_UINT       FUNC_MGT_DATA_TYPE_MASK(12)
+#define FUNC_MGT_DATA_TYPE_UBIGINT    FUNC_MGT_DATA_TYPE_MASK(13)
+#define FUNC_MGT_DATA_TYPE_VARCHAR    FUNC_MGT_DATA_TYPE_MASK(14)
+#define FUNC_MGT_DATA_TYPE_VARBINARY  FUNC_MGT_DATA_TYPE_MASK(15)
+#define FUNC_MGT_DATA_TYPE_JSON       FUNC_MGT_DATA_TYPE_MASK(16)
+#define FUNC_MGT_DATA_TYPE_DECIMAL    FUNC_MGT_DATA_TYPE_MASK(17)
+#define FUNC_MGT_DATA_TYPE_BLOB       FUNC_MGT_DATA_TYPE_MASK(18)
+
+#define FUNC_MGT_EXACT_NUMERIC_DATA_TYPE \
+  (FUNC_MGT_DATA_TYPE_TINYINT | FUNC_MGT_DATA_TYPE_SMALLINT | FUNC_MGT_DATA_TYPE_INT | FUNC_MGT_DATA_TYPE_BIGINT \
+      | FUNC_MGT_DATA_TYPE_UTINYINT | FUNC_MGT_DATA_TYPE_USMALLINT | FUNC_MGT_DATA_TYPE_UINT | FUNC_MGT_DATA_TYPE_UBIGINT)
+
+#define FUNC_MGT_APPRO_NUMERIC_DATA_TYPE (FUNC_MGT_DATA_TYPE_FLOAT | FUNC_MGT_DATA_TYPE_DOUBLE)
+
+#define FUNC_MGT_NUMERIC_DATA_TYPE (FUNC_MGT_EXACT_NUMERIC_DATA_TYPE | FUNC_MGT_APPRO_NUMERIC_DATA_TYPE)
+
+typedef void* FuncDef;
+
+typedef struct SFuncElement {
+  FuncDef (*defineFunc)();
+} SFuncElement;
+
+extern const SFuncElement gBuiltinFuncs[];
+
+FuncDef createFuncDef(const char* name, int32_t maxNumOfParams);
+FuncDef setOneParamSignature(FuncDef def, int64_t resDataType, int64_t paramDataType);
+FuncDef setTwoParamsSignature(FuncDef def, int64_t resDataType, int64_t p1DataType, int64_t p2DataType);
+FuncDef setFollowParamSignature(FuncDef def, int64_t paramDataType);
+FuncDef setFollowParamsSignature(FuncDef def, int64_t p1DataType, int64_t p2DataType, int32_t followNo);
+
+FuncDef setExecFuncs(FuncDef def, FExecGetEnv getEnv, FExecInit init, FExecProcess process, FExecFinalize finalize);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif  // _TD_FUNCTION_MGT_INT_H_
diff --git a/source/libs/function/inc/taggfunction.h b/source/libs/function/inc/taggfunction.h
index 41c7309a18d3ef702663f60ee25fffc0def7c7c2..9192c199513143eeaa8ad8095a22db26cc8a75d6 100644
--- a/source/libs/function/inc/taggfunction.h
+++ b/source/libs/function/inc/taggfunction.h
@@ -95,6 +95,10 @@ static FORCE_INLINE void initResultRowEntry(SResultRowEntryInfo *pResInfo, int32
   memset(GET_ROWCELL_INTERBUF(pResInfo), 0, bufLen);
 }
 
+#include "functionMgtInt.h"
+
+FuncDef defineCount();
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/source/libs/function/src/buildins.c b/source/libs/function/src/buildins.c
new file mode 100644
index 0000000000000000000000000000000000000000..ea2e9f3f2fb8deed2fa3738e02f40e3011bbd247
--- /dev/null
+++ b/source/libs/function/src/buildins.c
@@ -0,0 +1,21 @@
+/*
+ * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
+ *
+ * This program is free software: you can use, redistribute, and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3
+ * or later ("AGPL"), as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "functionMgtInt.h"
+#include "taggfunction.h"
+
+const SFuncElement gBuiltinFuncs[] = {
+  {.defineFunc = defineCount}
+};
diff --git a/source/libs/function/src/functionMgt.c b/source/libs/function/src/functionMgt.c
new file mode 100644
index 0000000000000000000000000000000000000000..c6ed2c8c03f9a728b40bb0f04eef4d11e667bdb4
--- /dev/null
+++ b/source/libs/function/src/functionMgt.c
@@ -0,0 +1,80 @@
+/*
+ * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
+ *
+ * This program is free software: you can use, redistribute, and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3
+ * or later ("AGPL"), as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "functionMgt.h"
+
+#include "functionMgtInt.h"
+#include "taos.h"
+#include "taoserror.h"
+#include "thash.h"
+
+typedef struct SFuncMgtService {
+  SHashObj* pFuncNameHashTable;
+} SFuncMgtService;
+
+static SFuncMgtService gFunMgtService;
+
+int32_t fmFuncMgtInit() {
+  gFunMgtService.pFuncNameHashTable = taosHashInit(128, taosGetDefaultHashFunction(TSDB_DATA_TYPE_BINARY), true, HASH_NO_LOCK);
+  if (NULL == gFunMgtService.pFuncNameHashTable) {
+    return TSDB_CODE_FAILED;
+  }
+  return TSDB_CODE_SUCCESS;
+}
+
+typedef struct SFuncDef {
+  char name[TSDB_FUNC_NAME_LEN];
+  int32_t maxNumOfParams;
+  SFuncExecFuncs execFuncs;
+} SFuncDef ;
+
+FuncDef createFuncDef(const char* name, int32_t maxNumOfParams) {
+  SFuncDef* pDef = calloc(1, sizeof(SFuncDef));
+  if (NULL == pDef) {
+    return NULL;
+  }
+  strcpy(pDef->name, name);
+  pDef->maxNumOfParams = maxNumOfParams;
+  return pDef;
+}
+
+FuncDef setOneParamSignature(FuncDef def, int64_t resDataType, int64_t paramDataType) {
+  // todo
+}
+
+FuncDef setTwoParamsSignature(FuncDef def, int64_t resDataType, int64_t p1DataType, int64_t p2DataType) {
+  // todo
+}
+
+FuncDef setFollowParamSignature(FuncDef def, int64_t paramDataType) {
+  // todo
+}
+
+FuncDef setFollowParamsSignature(FuncDef def, int64_t p1DataType, int64_t p2DataType, int32_t followNo) {
+  // todo
+}
+
+FuncDef setExecFuncs(FuncDef def, FExecGetEnv getEnv, FExecInit init, FExecProcess process, FExecFinalize finalize) {
+  SFuncDef* pDef = (SFuncDef*)def;
+  pDef->execFuncs.getEnv = getEnv;
+  pDef->execFuncs.init = init;
+  pDef->execFuncs.process = process;
+  pDef->execFuncs.finalize = finalize;
+  return def;
+}
+
+int32_t registerFunc(FuncDef func) {
+
+}
diff --git a/source/libs/function/src/taggfunction.c b/source/libs/function/src/taggfunction.c
index 3af4a8fe5772e1a36a0104cb42c1bad5d8f9998e..3b3edf1501f51d0b35b66fd31d351f528c688c84 100644
--- a/source/libs/function/src/taggfunction.c
+++ b/source/libs/function/src/taggfunction.c
@@ -4835,3 +4835,9 @@ SAggFunctionInfo aggFunc[35] = {{
                               statisRequired,
                           }
                           };
+
+FuncDef defineCount() {
+  FuncDef def = createFuncDef("count", 1);
+  // todo define signature
+  return setExecFuncs(def, NULL, function_setup, count_function, doFinalizer);
+}
diff --git a/source/libs/planner/src/logicPlan.c b/source/libs/planner/src/logicPlan.c
index 93f72bba9502aa73b86007c9a235ad8133598f89..a0feaca72b9f387733d4eb96c894dc2e1e1cffa9 100644
--- a/source/libs/planner/src/logicPlan.c
+++ b/source/libs/planner/src/logicPlan.c
@@ -212,7 +212,7 @@ static SQueryPlanNode* doAddTableColumnNode(const SQueryStmtInfo* pQueryInfo, SQ
       pExpr[i] = p;
     }
 
-    pNode = createQueryNode(QNODE_PROJECT, "Projection", &pNode, 1, pExpr, numOfCols, NULL);
+    // pNode = createQueryNode(QNODE_PROJECT, "Projection", &pNode, 1, pExpr, numOfCols, NULL);
     tfree(pExpr);
   }
 
diff --git a/source/libs/planner/src/physicalPlanJson.c b/source/libs/planner/src/physicalPlanJson.c
index c7a4e438baf026dfbbdce04c9640cad5c1adea3f..04282a2f80db355281f7da0c01561a44327a3297 100644
--- a/source/libs/planner/src/physicalPlanJson.c
+++ b/source/libs/planner/src/physicalPlanJson.c
@@ -109,6 +109,26 @@ static bool fromPnode(const cJSON* json, const char* name, FFromJson func, void*
   return func(jObj, *obj);
 }
 
+static bool fromPnodeArray(const cJSON* json, const char* name, FFromJson func, SArray** array) {
+  const cJSON* jArray = cJSON_GetObjectItem(json, name);
+  int32_t size = (NULL == jArray ? 0 : cJSON_GetArraySize(jArray));
+  if (size > 0) {
+    *array = taosArrayInit(size, POINTER_BYTES);
+    if (NULL == *array) {
+      return false;
+    }
+  }
+  for (int32_t i = 0; i < size; ++i) {
+    cJSON* jItem = cJSON_GetArrayItem(jArray, i);
+    void* item = calloc(1, getPnodeTypeSize(jItem));
+    if (NULL == item || !func(jItem, item)) {
+      return false;
+    }
+    taosArrayPush(*array, &item);
+  }
+  return true;
+}
+
 static bool addTarray(cJSON* json, const char* name, FToJson func, const SArray* array, bool isPoint) {
   size_t size = (NULL == array) ? 0 : taosArrayGetSize(array);
   if (size > 0) {
@@ -379,8 +399,8 @@ static const char* jkFunctionChild = "Child";
 static bool functionToJson(const void* obj, cJSON* jFunc) {
   const tExprNode* exprInfo = (const tExprNode*)obj;
   bool res = cJSON_AddStringToObject(jFunc, jkFunctionName, exprInfo->_function.functionName);
-  if (res) {
-    res = addRawArray(jFunc, jkFunctionChild, exprNodeToJson, exprInfo->_function.pChild, sizeof(tExprNode*), exprInfo->_function.num);
+  if (res && NULL != exprInfo->_function.pChild) {
+      res = addRawArray(jFunc, jkFunctionChild, exprNodeToJson, *(exprInfo->_function.pChild), sizeof(tExprNode*), exprInfo->_function.num);
   }
   return res;
 }
@@ -388,6 +408,10 @@ static bool functionToJson(const void* obj, cJSON* jFunc) {
 static bool functionFromJson(const cJSON* json, void* obj) {
   tExprNode* exprInfo = (tExprNode*)obj;
   copyString(json, jkFunctionName, exprInfo->_function.functionName);
+  exprInfo->_function.pChild = calloc(1, sizeof(tExprNode*));
+  if (NULL == exprInfo->_function.pChild) {
+    return false;
+  }
   return fromRawArrayWithAlloc(json, jkFunctionChild, exprNodeFromJson, (void**)exprInfo->_function.pChild, sizeof(tExprNode*), &exprInfo->_function.num);
 }
 
@@ -808,7 +832,7 @@ static bool specificPhyNodeFromJson(const cJSON* json, void* obj) {
     case OP_SystemTableScan:
       return scanNodeFromJson(json, obj);
     case OP_Aggregate:
-      break; // todo
+      return aggNodeFromJson(json, obj);
     case OP_Project:
       return true;
     // case OP_Groupby:
@@ -879,7 +903,7 @@ static bool phyNodeFromJson(const cJSON* json, void* obj) {
     res = fromObject(json, jkPnodeSchema, dataBlockSchemaFromJson, &node->targetSchema, true);
   }
   if (res) {
-    res = fromArray(json, jkPnodeChildren, phyNodeFromJson, &node->pChildren, sizeof(SSlotSchema));
+    res = fromPnodeArray(json, jkPnodeChildren, phyNodeFromJson, &node->pChildren);
   }
   if (res) {
     res = fromObject(json, node->info.name, specificPhyNodeFromJson, node, true);
diff --git a/source/nodes/CMakeLists.txt b/source/nodes/CMakeLists.txt
new file mode 100644
index 0000000000000000000000000000000000000000..b30534f3f2e66b412396b7b7980c7629b8a87a02
--- /dev/null
+++ b/source/nodes/CMakeLists.txt
@@ -0,0 +1,15 @@
+aux_source_directory(src NODES_SRC)
+add_library(nodes STATIC ${NODES_SRC})
+target_include_directories(
+    nodes
+    PUBLIC "${CMAKE_SOURCE_DIR}/include/nodes"
+    PRIVATE "${CMAKE_CURRENT_SOURCE_DIR}/inc"
+)
+target_link_libraries(
+    nodes
+    PRIVATE os util
+)
+
+if(${BUILD_TEST})
+    ADD_SUBDIRECTORY(test)
+endif(${BUILD_TEST})
\ No newline at end of file
diff --git a/source/nodes/src/nodesClone.c b/source/nodes/src/nodesClone.c
new file mode 100644
index 0000000000000000000000000000000000000000..04f6df56234738188caafcf7c40972c62c6173fa
--- /dev/null
+++ b/source/nodes/src/nodesClone.c
@@ -0,0 +1,20 @@
+/*
+ * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
+ *
+ * This program is free software: you can use, redistribute, and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3
+ * or later ("AGPL"), as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "nodes.h"
+
+void cloneNode(const SNode* pNode) {
+
+}
diff --git a/source/nodes/src/nodesCode.c b/source/nodes/src/nodesCode.c
new file mode 100644
index 0000000000000000000000000000000000000000..7fe919ffe8219a84c84d2b51ce30225d0152d796
--- /dev/null
+++ b/source/nodes/src/nodesCode.c
@@ -0,0 +1,24 @@
+/*
+ * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
+ *
+ * This program is free software: you can use, redistribute, and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3
+ * or later ("AGPL"), as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "nodes.h"
+
+int32_t nodeToString(const SNode* pNode, char** pStr, int32_t* pLen) {
+
+}
+
+int32_t stringToNode(const char* pStr, SNode** pNode) {
+
+}
diff --git a/source/nodes/src/nodesEqual.c b/source/nodes/src/nodesEqual.c
new file mode 100644
index 0000000000000000000000000000000000000000..bef025fbea0ea4d8d43d444e461b2493f3fa64b2
--- /dev/null
+++ b/source/nodes/src/nodesEqual.c
@@ -0,0 +1,141 @@
+/*
+ * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
+ *
+ * This program is free software: you can use, redistribute, and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3
+ * or later ("AGPL"), as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "nodes.h"
+
+#define COMPARE_SCALAR_FIELD(fldname) \
+	do { \
+		if (a->fldname != b->fldname) \
+			return false; \
+	} while (0)
+
+#define COMPARE_STRING(a, b)	\
+	(((a) != NULL && (b) != NULL) ? (strcmp(a, b) == 0) : (a) == (b))
+
+#define COMPARE_STRING_FIELD(fldname) \
+	do { \
+		if (!COMPARE_STRING(a->fldname, b->fldname)) \
+			return false; \
+	} while (0)
+
+#define COMPARE_NODE_FIELD(fldname) \
+	do { \
+		if (!nodeEqual(a->fldname, b->fldname)) \
+			return false; \
+	} while (0)
+
+#define COMPARE_ARRAY_FIELD(fldname) \
+	do { \
+		if (!nodeArrayEqual(a->fldname, b->fldname)) \
+			return false; \
+	} while (0)
+
+static bool nodeArrayEqual(const SArray* a, const SArray* b) {
+  if (a == b) {
+    return true;
+  }
+
+  if (NULL == a || NULL == b) {
+    return false;
+  }
+
+  if (taosArrayGetSize(a) != taosArrayGetSize(b)) {
+    return false;
+  }
+
+  size_t size = taosArrayGetSize(a);
+  for (size_t i = 0; i < size; ++i) {
+    if (!nodeEqual((SNode*)taosArrayGetP(a, i), (SNode*)taosArrayGetP(b, i))) {
+      return false;
+    }
+  }
+  return true;
+}
+
+static bool columnNodeEqual(const SColumnNode* a, const SColumnNode* b) {
+  COMPARE_STRING_FIELD(dbName);
+  COMPARE_STRING_FIELD(tableName);
+  COMPARE_STRING_FIELD(colName);
+  return true;
+}
+
+static bool valueNodeEqual(const SValueNode* a, const SValueNode* b) {
+  COMPARE_STRING_FIELD(literal);
+  return true;
+}
+
+static bool operatorNodeEqual(const SOperatorNode* a, const SOperatorNode* b) {
+  COMPARE_SCALAR_FIELD(opType);
+  COMPARE_NODE_FIELD(pLeft);
+  COMPARE_NODE_FIELD(pRight);
+  return true;
+}
+
+static bool logicConditionNodeEqual(const SLogicConditionNode* a, const SLogicConditionNode* b) {
+  COMPARE_SCALAR_FIELD(condType);
+  COMPARE_ARRAY_FIELD(pParameterList);
+  return true;
+}
+
+static bool isNullConditionNodeEqual(const SIsNullCondNode* a, const SIsNullCondNode* b) {
+  COMPARE_NODE_FIELD(pExpr);
+  COMPARE_SCALAR_FIELD(isNot);
+  return true;
+}
+
+static bool functionNodeEqual(const SFunctionNode* a, const SFunctionNode* b) {
+  COMPARE_SCALAR_FIELD(funcId);
+  COMPARE_ARRAY_FIELD(pParameterList);
+  return true;
+}
+
+bool nodeEqual(const SNode* a, const SNode* b) {
+  if (a == b) {
+    return true;
+  }
+
+  if (NULL == a || NULL == b) {
+    return false;
+  }
+
+  if (nodeType(a) != nodeType(b)) {
+    return false;
+  }
+
+  switch (nodeType(a)) {
+    case QUERY_NODE_COLUMN:
+      return columnNodeEqual((const SColumnNode*)a, (const SColumnNode*)b);
+    case QUERY_NODE_VALUE:
+      return valueNodeEqual((const SValueNode*)a, (const SValueNode*)b);
+    case QUERY_NODE_OPERATOR:
+      return operatorNodeEqual((const SOperatorNode*)a, (const SOperatorNode*)b);
+    case QUERY_NODE_LOGIC_CONDITION:
+      return logicConditionNodeEqual((const SLogicConditionNode*)a, (const SLogicConditionNode*)b);
+    case QUERY_NODE_IS_NULL_CONDITION:
+      return isNullConditionNodeEqual((const SIsNullCondNode*)a, (const SIsNullCondNode*)b);
+    case QUERY_NODE_FUNCTION:
+      return functionNodeEqual((const SFunctionNode*)a, (const SFunctionNode*)b);
+    case QUERY_NODE_REAL_TABLE:
+    case QUERY_NODE_TEMP_TABLE:
+    case QUERY_NODE_JOIN_TABLE:
+    case QUERY_NODE_GROUPING_SET:
+    case QUERY_NODE_ORDER_BY_EXPR:
+      return false; // todo
+    default:
+      break;
+  }
+
+  return false;
+}
diff --git a/source/nodes/src/nodesTraverse.c b/source/nodes/src/nodesTraverse.c
new file mode 100644
index 0000000000000000000000000000000000000000..eac82880991234c0c22ad06eb4eb7bf24acae6cc
--- /dev/null
+++ b/source/nodes/src/nodesTraverse.c
@@ -0,0 +1,83 @@
+/*
+ * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
+ *
+ * This program is free software: you can use, redistribute, and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3
+ * or later ("AGPL"), as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "nodes.h"
+
+typedef bool (*FQueryNodeWalker)(SNode* pNode, void* pContext);
+
+bool nodeArrayWalker(SArray* pArray, FQueryNodeWalker walker, void* pContext) {
+    size_t size = taosArrayGetSize(pArray);
+    for (size_t i = 0; i < size; ++i) {
+      if (!nodeTreeWalker((SNode*)taosArrayGetP(pArray, i), walker, pContext)) {
+        return false;
+      }
+    }
+    return true;
+}
+
+bool nodeTreeWalker(SNode* pNode, FQueryNodeWalker walker, void* pContext) {
+  if (NULL == pNode) {
+    return true;
+  }
+
+  if (!walker(pNode, pContext)) {
+    return false;
+  }
+
+  switch (nodeType(pNode)) {
+    case QUERY_NODE_COLUMN:
+    case QUERY_NODE_VALUE:
+      // these node types with no subnodes
+      return true;
+    case QUERY_NODE_OPERATOR: {
+      SOperatorNode* pOpNode = (SOperatorNode*)pNode;
+      if (!nodeTreeWalker(pOpNode->pLeft, walker, pContext)) {
+        return false;
+      }
+      return nodeTreeWalker(pOpNode->pRight, walker, pContext);
+    }
+    case QUERY_NODE_LOGIC_CONDITION:
+      return nodeArrayWalker(((SLogicConditionNode*)pNode)->pParameterList, walker, pContext);
+    case QUERY_NODE_IS_NULL_CONDITION:
+      return nodeTreeWalker(((SIsNullCondNode*)pNode)->pExpr, walker, pContext);
+    case QUERY_NODE_FUNCTION:
+      return nodeArrayWalker(((SFunctionNode*)pNode)->pParameterList, walker, pContext);
+    case QUERY_NODE_REAL_TABLE:
+    case QUERY_NODE_TEMP_TABLE:
+      return true; // todo
+    case QUERY_NODE_JOIN_TABLE: {
+      SJoinTableNode* pJoinTableNode = (SJoinTableNode*)pNode;
+      if (!nodeTreeWalker(pJoinTableNode->pLeft, walker, pContext)) {
+        return false;
+      }
+      if (!nodeTreeWalker(pJoinTableNode->pRight, walker, pContext)) {
+        return false;
+      }
+      return nodeTreeWalker(pJoinTableNode->pOnCond, walker, pContext);
+    }
+    case QUERY_NODE_GROUPING_SET:
+      return nodeArrayWalker(((SGroupingSetNode*)pNode)->pParameterList, walker, pContext);
+    case QUERY_NODE_ORDER_BY_EXPR:
+      return nodeTreeWalker(((SOrderByExprNode*)pNode)->pExpr, walker, pContext);
+    default:
+      break;
+  }
+
+  return false;
+}
+
+bool stmtWalker(SNode* pNode, FQueryNodeWalker walker, void* pContext) {
+
+}
diff --git a/source/nodes/src/nodesUtil.c b/source/nodes/src/nodesUtil.c
new file mode 100644
index 0000000000000000000000000000000000000000..fe5883d809bd9a29e1381295d363c52a2067aed0
--- /dev/null
+++ b/source/nodes/src/nodesUtil.c
@@ -0,0 +1,24 @@
+/*
+ * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
+ *
+ * This program is free software: you can use, redistribute, and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3
+ * or later ("AGPL"), as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "nodes.h"
+
+bool isTimeorderQuery(const SNode* pQuery) {
+
+}
+
+bool isTimelineQuery(const SNode* pQuery) {
+
+}
diff --git a/source/nodes/test/CMakeLists.txt b/source/nodes/test/CMakeLists.txt
new file mode 100644
index 0000000000000000000000000000000000000000..80725a79fbc8cd80d75ca9198752967eb1af7dec
--- /dev/null
+++ b/source/nodes/test/CMakeLists.txt
@@ -0,0 +1,19 @@
+
+MESSAGE(STATUS "build nodes unit test")
+
+# GoogleTest requires at least C++11
+SET(CMAKE_CXX_STANDARD 11)
+AUX_SOURCE_DIRECTORY(${CMAKE_CURRENT_SOURCE_DIR} SOURCE_LIST)
+
+ADD_EXECUTABLE(nodesTest ${SOURCE_LIST})
+
+TARGET_INCLUDE_DIRECTORIES(
+        nodesTest
+        PUBLIC "${CMAKE_SOURCE_DIR}/include/nodes/"
+        PRIVATE "${CMAKE_SOURCE_DIR}/source/nodes/inc"
+)
+
+TARGET_LINK_LIBRARIES(
+        nodesTest
+        PUBLIC os util common nodes gtest
+)
diff --git a/source/nodes/test/nodesTest.cpp b/source/nodes/test/nodesTest.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..7df3cd8b4c63738c22f0fdd7f45221c24d6e16d3
--- /dev/null
+++ b/source/nodes/test/nodesTest.cpp
@@ -0,0 +1,25 @@
+/*
+ * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
+ *
+ * This program is free software: you can use, redistribute, and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3
+ * or later ("AGPL"), as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <gtest/gtest.h>
+
+TEST(NodesTest, traverseTest) {
+  // todo
+}
+
+int main(int argc, char* argv[]) {
+	testing::InitGoogleTest(&argc, argv);
+	return RUN_ALL_TESTS();
+}