diff --git a/include/common/taosmsg.h b/include/common/taosmsg.h
index 98798a6235..11a38a3742 100644
--- a/include/common/taosmsg.h
+++ b/include/common/taosmsg.h
@@ -51,6 +51,8 @@ TAOS_DEFINE_MESSAGE_TYPE( TSDB_MSG_TYPE_MQ_QUERY, "mq-query" )
 TAOS_DEFINE_MESSAGE_TYPE( TSDB_MSG_TYPE_MQ_CONNECT, "mq-connect" )
 TAOS_DEFINE_MESSAGE_TYPE( TSDB_MSG_TYPE_MQ_DISCONNECT, "mq-disconnect" )
 TAOS_DEFINE_MESSAGE_TYPE( TSDB_MSG_TYPE_MQ_SET, "mq-set" )
+TAOS_DEFINE_MESSAGE_TYPE( TSDB_MSG_TYPE_RSP_READY, "rsp-ready" )
+
 // message from client to mnode
 TAOS_DEFINE_MESSAGE_TYPE( TSDB_MSG_TYPE_CONNECT, "connect" )
 TAOS_DEFINE_MESSAGE_TYPE( TSDB_MSG_TYPE_CREATE_ACCT, "create-acct" )	
@@ -232,9 +234,9 @@ typedef struct {
 } SEpAddrMsg;
 
 typedef struct {
-  char    *fqdn;
+  char     fqdn[TSDB_FQDN_LEN];
   uint16_t port;
-} SEpAddr1;
+} SEpAddr;
 
 typedef struct {
   int32_t numOfVnodes;
@@ -1079,6 +1081,24 @@ typedef struct {
   /* data */
 } SUpdateTagValRsp;
 
+typedef struct SSchedulerQueryMsg {
+  uint64_t  queryId;
+  uint64_t  taskId;
+  uint32_t  contentLen;
+  char      msg[];
+} SSchedulerQueryMsg;
+
+typedef struct SSchedulerReadyMsg {
+  uint64_t  queryId;
+  uint64_t  taskId;
+} SSchedulerReadyMsg;
+
+typedef struct SSchedulerFetchMsg {
+  uint64_t  queryId;
+  uint64_t  taskId;
+} SSchedulerFetchMsg;
+
+
 #pragma pack(pop)
 
 #ifdef __cplusplus
diff --git a/include/libs/catalog/catalog.h b/include/libs/catalog/catalog.h
index ee626865fb..68eae03f51 100644
--- a/include/libs/catalog/catalog.h
+++ b/include/libs/catalog/catalog.h
@@ -137,7 +137,7 @@ int32_t catalogGetTableHashVgroup(struct SCatalog* pCatalog, void *pRpc, const S
 int32_t catalogGetAllMeta(struct SCatalog* pCatalog, void *pRpc, const SEpSet* pMgmtEps, const SCatalogReq* pReq, SMetaData* pRsp);
 
 
-int32_t catalogGetQnodeList(struct SCatalog* pCatalog, const SEpSet* pMgmtEps, SEpSet* pQnodeEpSet);
+int32_t catalogGetQnodeList(struct SCatalog* pCatalog, void *pRpc, const SEpSet* pMgmtEps, SEpSet* pQnodeEpSet);
 
 
 
diff --git a/include/libs/planner/planner.h b/include/libs/planner/planner.h
index 3f4d21a746..8b54b88b28 100644
--- a/include/libs/planner/planner.h
+++ b/include/libs/planner/planner.h
@@ -141,8 +141,8 @@ int32_t qCreateQueryDag(const struct SQueryStmtInfo* pQueryInfo, struct SEpSet*
 // Set datasource of this subplan, multiple calls may be made to a subplan.
 // @subplan subplan to be schedule
 // @templateId templateId of a group of datasource subplans of this @subplan
-// @eps Execution location of this group of datasource subplans, is an array of SEpAddr structures 
-int32_t qSetSubplanExecutionNode(SSubplan* subplan, uint64_t templateId, SArray* eps);
+// @ep one execution location of this group of datasource subplans 
+int32_t qSetSubplanExecutionNode(SSubplan* subplan, uint64_t templateId, SEpAddr* ep);
 
 int32_t qExplainQuery(const struct SQueryStmtInfo* pQueryInfo, struct SEpSet* pQnode, char** str);
 
diff --git a/include/libs/scheduler/scheduler.h b/include/libs/scheduler/scheduler.h
index 40c85520d4..c01b79d7ff 100644
--- a/include/libs/scheduler/scheduler.h
+++ b/include/libs/scheduler/scheduler.h
@@ -21,9 +21,10 @@ extern "C" {
 #endif
 
 #include "planner.h"
+#include "catalog.h"
 
 typedef struct SSchedulerCfg {
-
+  int32_t clusterType;
 } SSchedulerCfg;
 
 typedef struct SQueryProfileSummary {
@@ -55,9 +56,9 @@ typedef struct SQueryProfileSummary {
  * @param pJob
  * @return
  */
-int32_t scheduleQueryJob(SQueryDag* pDag, void** pJob);
+int32_t scheduleQueryJob(struct SCatalog *pCatalog, void *pRpc, const SEpSet* pMgmtEps, SQueryDag* pDag, void** pJob);
 
-int32_t scheduleFetchRows(void *pJob, void *data);
+int32_t scheduleFetchRows(void *pJob, void **data);
 
 
 /**
diff --git a/include/util/taoserror.h b/include/util/taoserror.h
index ad4b383d03..75aab24f83 100644
--- a/include/util/taoserror.h
+++ b/include/util/taoserror.h
@@ -493,6 +493,7 @@ int32_t* taosGetErrno();
 
 //scheduler
 #define TSDB_CODE_SCH_STATUS_ERROR              TAOS_DEF_ERROR_CODE(0, 0x2501)  //scheduler status error
+#define TSDB_CODE_SCH_INTERNAL_ERROR            TAOS_DEF_ERROR_CODE(0, 0x2502)  //scheduler internal error
 
 
 
diff --git a/source/libs/catalog/src/catalog.c b/source/libs/catalog/src/catalog.c
index 32cedb82b0..1134c7763a 100644
--- a/source/libs/catalog/src/catalog.c
+++ b/source/libs/catalog/src/catalog.c
@@ -634,6 +634,16 @@ _return:
   CTG_RET(code);
 }
 
+int32_t catalogGetQnodeList(struct SCatalog* pCatalog, void *pRpc, const SEpSet* pMgmtEps, SEpSet* pQnodeEpSet) {
+  if (NULL == pCatalog || NULL == pRpc  || NULL == pMgmtEps || NULL == pQnodeEpSet) {
+    CTG_ERR_RET(TSDB_CODE_CTG_INVALID_INPUT);
+  }
+
+
+  return TSDB_CODE_SUCCESS;
+}
+
+
 void catalogDestroy(void) {
   if (ctgMgmt.pCluster) {
     taosHashCleanup(ctgMgmt.pCluster); //TBD
diff --git a/source/libs/planner/inc/plannerInt.h b/source/libs/planner/inc/plannerInt.h
index 19563a8a0c..c9b7b6d235 100644
--- a/source/libs/planner/inc/plannerInt.h
+++ b/source/libs/planner/inc/plannerInt.h
@@ -100,7 +100,7 @@ int32_t queryPlanToString(struct SQueryPlanNode* pQueryNode, char** str);
 int32_t queryPlanToSql(struct SQueryPlanNode* pQueryNode, char** sql);
 
 int32_t createDag(SQueryPlanNode* pQueryNode, struct SCatalog* pCatalog, SQueryDag** pDag);
-int32_t setSubplanExecutionNode(SSubplan* subplan, uint64_t templateId, SArray* eps);
+int32_t setSubplanExecutionNode(SSubplan* subplan, uint64_t templateId, SEpAddr* ep);
 int32_t subPlanToString(const SSubplan *pPhyNode, char** str);
 int32_t stringToSubplan(const char* str, SSubplan** subplan);
 
diff --git a/source/libs/planner/src/physicalPlan.c b/source/libs/planner/src/physicalPlan.c
index f187ec0ec9..72b30012c8 100644
--- a/source/libs/planner/src/physicalPlan.c
+++ b/source/libs/planner/src/physicalPlan.c
@@ -225,6 +225,6 @@ int32_t createDag(SQueryPlanNode* pQueryNode, struct SCatalog* pCatalog, SQueryD
   return TSDB_CODE_SUCCESS;
 }
 
-int32_t setSubplanExecutionNode(SSubplan* subplan, uint64_t templateId, SArray* eps) {
+int32_t setSubplanExecutionNode(SSubplan* subplan, uint64_t templateId, SEpAddr* ep) {
   //todo
 }
diff --git a/source/libs/planner/src/planner.c b/source/libs/planner/src/planner.c
index 3a90acb5fd..e9a4591d4a 100644
--- a/source/libs/planner/src/planner.c
+++ b/source/libs/planner/src/planner.c
@@ -46,8 +46,8 @@ int32_t qCreateQueryDag(const struct SQueryStmtInfo* pQueryInfo, struct SEpSet*
   return TSDB_CODE_SUCCESS;
 }
 
-int32_t qSetSubplanExecutionNode(SSubplan* subplan, uint64_t templateId, SArray* eps) {
-  return setSubplanExecutionNode(subplan, templateId, eps);
+int32_t qSetSubplanExecutionNode(SSubplan* subplan, uint64_t templateId, SEpAddr* ep) {
+  return setSubplanExecutionNode(subplan, templateId, ep);
 }
 
 int32_t qSubPlanToString(const SSubplan *subplan, char** str) {
diff --git a/source/libs/scheduler/CMakeLists.txt b/source/libs/scheduler/CMakeLists.txt
index 31f1c25bea..cdb4e08205 100644
--- a/source/libs/scheduler/CMakeLists.txt
+++ b/source/libs/scheduler/CMakeLists.txt
@@ -9,5 +9,5 @@ target_include_directories(
 
 target_link_libraries(
         scheduler
-        PRIVATE os util planner qcom common
-)
\ No newline at end of file
+        PRIVATE os util planner qcom common catalog transport
+)
diff --git a/source/libs/scheduler/inc/schedulerInt.h b/source/libs/scheduler/inc/schedulerInt.h
index 4620a816da..db75fc4fdd 100644
--- a/source/libs/scheduler/inc/schedulerInt.h
+++ b/source/libs/scheduler/inc/schedulerInt.h
@@ -27,6 +27,9 @@ extern "C" {
 #include "thash.h"
 
 #define SCHEDULE_DEFAULT_JOB_NUMBER 1000
+#define SCHEDULE_DEFAULT_TASK_NUMBER 1000
+
+#define SCH_MAX_CONDIDATE_EP_NUM TSDB_MAX_REPLICA
 
 enum {
   SCH_STATUS_NOT_START = 1,
@@ -39,22 +42,27 @@ enum {
 
 typedef struct SSchedulerMgmt {
   uint64_t  taskId;
+  SSchedulerCfg cfg;
   SHashObj *Jobs;  // key: queryId, value: SQueryJob*
 } SSchedulerMgmt;
 
 typedef struct SQueryTask {
-  uint64_t             taskId;  // task id
-  char                *msg;     // operator tree
-  int8_t               status;  // task status
-  SQueryProfileSummary summary; // task execution summary
+  uint64_t             taskId;     // task id
+  SSubplan            *plan;       // subplan
+  char                *msg;        // operator tree
+  int8_t               status;     // task status
+  SEpAddr              execAddr;   // task actual executed node address
+  SQueryProfileSummary summary;    // task execution summary
+  int32_t              childReady; // child task ready number
+  SArray              *children;   // the datasource tasks,from which to fetch the result, element is SQueryTask*
+  SArray              *parents;    // the data destination tasks, get data from current task, element is SQueryTask*
 } SQueryTask;
 
 typedef struct SQueryLevel {
+  int32_t level;
   int8_t  status;
   int32_t taskNum;
-  
   SArray *subTasks;  // Element is SQueryTask
-  SArray *subPlans;  // Element is SSubplan
 } SQueryLevel;
 
 typedef struct SQueryJob {
@@ -63,13 +71,29 @@ typedef struct SQueryJob {
   int32_t   levelIdx;
   int8_t    status;
   SQueryProfileSummary summary;
-  
-  SArray  *levels;    // Element is SQueryLevel, starting from 0.
-  SArray  *subPlans;  // Element is SArray*, and nested element is SSubplan. The execution level of subplan, starting from 0.
+  SEpSet    dataSrcEps;
+  SEpAddr   resEp;
+  struct SCatalog *catalog;
+  void            *rpc;
+  SEpSet          *mgmtEpSet;
+  tsem_t           rspSem;
+  int32_t          userFetch;
+  int32_t          remoteFetch;
+  void            *res;
+
+  SHashObj *execTasks; // executing tasks, key:taskid, value:SQueryTask*
+  SHashObj *succTasks; // succeed tasks, key:taskid, value:SQueryTask*
+    
+  SArray   *levels;    // Element is SQueryLevel, starting from 0.
+  SArray   *subPlans;  // Element is SArray*, and nested element is SSubplan. The execution level of subplan, starting from 0.
 } SQueryJob;
 
+#define SCH_HAS_QNODE_IN_CLUSTER(type) (false) //TODO CLUSTER TYPE
+#define SCH_TASK_READY_TO_LUNCH(task) ((task)->childReady >= taosArrayGetSize((task)->children))   // MAY NEED TO ENHANCE
+#define SCH_IS_DATA_SRC_TASK(task) (task->plan->type == QUERY_TYPE_SCAN)
 
 #define SCH_JOB_ERR_LOG(param, ...) qError("QID:%"PRIx64 param, job->queryId, __VA_ARGS__)
+#define SCH_TASK_ERR_LOG(param, ...) qError("QID:%"PRIx64",TID:%"PRIx64 param, job->queryId, task->taskId, __VA_ARGS__)
 
 #define SCH_ERR_RET(c) do { int32_t _code = c; if (_code != TSDB_CODE_SUCCESS) { terrno = _code; return _code; } } while (0)
 #define SCH_RET(c) do { int32_t _code = c; if (_code != TSDB_CODE_SUCCESS) { terrno = _code; } return _code; } while (0)
@@ -77,6 +101,8 @@ typedef struct SQueryJob {
 #define SCH_ERR_JRET(c) do { code = c; if (code != TSDB_CODE_SUCCESS) { terrno = code; goto _return; } } while (0)
 
 
+extern int32_t schLaunchTask(SQueryJob *job, SQueryTask *task);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/source/libs/scheduler/src/scheduler.c b/source/libs/scheduler/src/scheduler.c
index 7d387cbc66..2327fc5b04 100644
--- a/source/libs/scheduler/src/scheduler.c
+++ b/source/libs/scheduler/src/scheduler.c
@@ -16,6 +16,7 @@
 #include "schedulerInt.h"
 #include "taosmsg.h"
 #include "query.h"
+#include "catalog.h"
 
 SSchedulerMgmt schMgmt = {0};
 
@@ -50,23 +51,109 @@ int32_t schBuildAndSendRequest(void *pRpc, const SEpSet* pMgmtEps, __taos_async_
 */  
 }
 
+int32_t schBuildTaskRalation(SQueryJob *job, SHashObj *planToTask) {
+  for (int32_t i = 0; i < job->levelNum; ++i) {
+    SQueryLevel *level = taosArrayGet(job->levels, i);
+    
+    for (int32_t m = 0; m < level->taskNum; ++m) {
+      SQueryTask *task = taosArrayGet(level->subTasks, m);
+      SSubplan *plan = task->plan;
+      int32_t childNum = (int32_t)taosArrayGetSize(plan->pChildern);
+      int32_t parentNum = (int32_t)taosArrayGetSize(plan->pParents);
+
+      if (childNum > 0) {
+        task->children = taosArrayInit(childNum, POINTER_BYTES);
+        if (NULL == task->children) {
+          qError("taosArrayInit %d failed", childNum);
+          SCH_ERR_RET(TSDB_CODE_QRY_OUT_OF_MEMORY);
+        }
+      }
+
+      for (int32_t n = 0; n < childNum; ++n) {
+        SSubplan *child = taosArrayGet(plan->pChildern, n);
+        SQueryTask *childTask = taosHashGet(planToTask, &child, POINTER_BYTES);
+        if (childTask) {
+          qError("subplan relationship error, level:%d, taskIdx:%d, childIdx:%d", i, m, n);
+          SCH_ERR_RET(TSDB_CODE_SCH_INTERNAL_ERROR);
+        }
+
+        if (NULL == taosArrayPush(task->children, &childTask)) {
+          qError("taosArrayPush failed");
+          SCH_ERR_RET(TSDB_CODE_QRY_OUT_OF_MEMORY);
+        }
+      }
+
+      if (parentNum > 0) {
+        task->parents = taosArrayInit(parentNum, POINTER_BYTES);
+        if (NULL == task->parents) {
+          qError("taosArrayInit %d failed", parentNum);
+          SCH_ERR_RET(TSDB_CODE_QRY_OUT_OF_MEMORY);
+        }
+      }
+
+      for (int32_t n = 0; n < parentNum; ++n) {
+        SSubplan *parent = taosArrayGet(plan->pParents, n);
+        SQueryTask *parentTask = taosHashGet(planToTask, &parent, POINTER_BYTES);
+        if (parentTask) {
+          qError("subplan relationship error, level:%d, taskIdx:%d, childIdx:%d", i, m, n);
+          SCH_ERR_RET(TSDB_CODE_SCH_INTERNAL_ERROR);
+        }
+
+        if (NULL == taosArrayPush(task->parents, &parentTask)) {
+          qError("taosArrayPush failed");
+          SCH_ERR_RET(TSDB_CODE_QRY_OUT_OF_MEMORY);
+        }
+      }      
+    }
+  }
+
+  SQueryLevel *level = taosArrayGet(job->levels, 0);
+  if (level->taskNum > 1) {
+    qError("invalid plan info, level 0, taskNum:%d", level->taskNum);
+    SCH_ERR_RET(TSDB_CODE_SCH_INTERNAL_ERROR);
+  }
+
+  SQueryTask *task = taosArrayGet(level->subTasks, 0);
+  if (task->parents && taosArrayGetSize(task->parents) > 0) {
+    qError("invalid plan info, level 0, parentNum:%d", (int32_t)taosArrayGetSize(task->parents));
+    SCH_ERR_RET(TSDB_CODE_SCH_INTERNAL_ERROR);
+  }
+
+
+  return TSDB_CODE_SUCCESS;
+}
+
+
 int32_t schValidateAndBuildJob(SQueryDag *dag, SQueryJob *job) {
   int32_t code = 0;
+
+  job->queryId = dag->queryId;
+  
+  if (dag->numOfSubplans <= 0) {
+    qError("invalid subplan num:%d", dag->numOfSubplans);
+    SCH_ERR_RET(TSDB_CODE_QRY_INVALID_INPUT);
+  }
+  
   int32_t levelNum = (int32_t)taosArrayGetSize(dag->pSubplans);
   if (levelNum <= 0) {
     qError("invalid level num:%d", levelNum);
     SCH_ERR_RET(TSDB_CODE_QRY_INVALID_INPUT);
   }
 
+  SHashObj *planToTask = taosHashInit(SCHEDULE_DEFAULT_TASK_NUMBER, taosGetDefaultHashFunction(POINTER_BYTES == sizeof(int64_t) ? TSDB_DATA_TYPE_BIGINT : TSDB_DATA_TYPE_INT), false, HASH_NO_LOCK);
+  if (NULL == planToTask) {
+    qError("taosHashInit %d failed", SCHEDULE_DEFAULT_TASK_NUMBER);
+    SCH_ERR_RET(TSDB_CODE_QRY_OUT_OF_MEMORY);
+  }
+  
   job->levels = taosArrayInit(levelNum, sizeof(SQueryLevel));
   if (NULL == job->levels) {
     qError("taosArrayInit %d failed", levelNum);
-    SCH_ERR_RET(TSDB_CODE_QRY_OUT_OF_MEMORY);
+    SCH_ERR_JRET(TSDB_CODE_QRY_OUT_OF_MEMORY);
   }
 
   job->levelNum = levelNum;
   job->levelIdx = levelNum - 1;
-  job->status = SCH_STATUS_NOT_START;
 
   job->subPlans = dag->pSubplans;
 
@@ -77,32 +164,39 @@ int32_t schValidateAndBuildJob(SQueryDag *dag, SQueryJob *job) {
   level.status = SCH_STATUS_NOT_START;
 
   for (int32_t i = 0; i < levelNum; ++i) {
+    level.level = i;
     levelPlans = taosArrayGetP(dag->pSubplans, i);
     if (NULL == levelPlans) {
       qError("no level plans for level %d", i);
-      SCH_ERR_RET(TSDB_CODE_QRY_INVALID_INPUT);
+      SCH_ERR_JRET(TSDB_CODE_QRY_INVALID_INPUT);
     }
 
     levelPlanNum = (int32_t)taosArrayGetSize(levelPlans);
     if (levelPlanNum <= 0) {
       qError("invalid level plans number:%d, level:%d", levelPlanNum, i);
-      SCH_ERR_RET(TSDB_CODE_QRY_INVALID_INPUT);
+      SCH_ERR_JRET(TSDB_CODE_QRY_INVALID_INPUT);
     }
 
     level.taskNum = levelPlanNum;
-    level.subPlans = levelPlans;
     
     level.subTasks = taosArrayInit(levelPlanNum, sizeof(SQueryTask));
     if (NULL == level.subTasks) {
       qError("taosArrayInit %d failed", levelPlanNum);
-      SCH_ERR_RET(TSDB_CODE_QRY_OUT_OF_MEMORY);
+      SCH_ERR_JRET(TSDB_CODE_QRY_OUT_OF_MEMORY);
     }
     
     for (int32_t n = 0; n < levelPlanNum; ++n) {
+      SSubplan *plan = taosArrayGet(levelPlans, n);
       SQueryTask *task = taosArrayGet(level.subTasks, n);
       
       task->taskId = atomic_add_fetch_64(&schMgmt.taskId, 1);
+      task->plan = plan;
       task->status = SCH_STATUS_NOT_START;
+
+      if (0 != taosHashPut(planToTask, &plan, POINTER_BYTES, &task, POINTER_BYTES)) {
+        qError("taosHashPut failed");
+        SCH_ERR_JRET(TSDB_CODE_QRY_OUT_OF_MEMORY);
+      }
     }
 
     if (NULL == taosArrayPush(job->levels, &level)) {
@@ -111,6 +205,12 @@ int32_t schValidateAndBuildJob(SQueryDag *dag, SQueryJob *job) {
     }
   }
 
+  SCH_ERR_JRET(schBuildTaskRalation(job, planToTask));
+
+  if (planToTask) {
+    taosHashCleanup(planToTask);
+  }
+  
   return TSDB_CODE_SUCCESS;
 
 _return:
@@ -118,20 +218,319 @@ _return:
     taosArrayDestroy(level.subTasks);
   }
 
+  if (planToTask) {
+    taosHashCleanup(planToTask);
+  }
+
   SCH_RET(code);
 }
 
-
-int32_t schJobExecute(SQueryJob *job) {
-  switch (job->status) {
-    case SCH_STATUS_NOT_START:
-
-      break;
-      
-    default:
-      SCH_JOB_ERR_LOG("invalid job status:%d", job->status);
-      SCH_ERR_RET(TSDB_CODE_SCH_STATUS_ERROR);
+int32_t schAvailableEpSet(SQueryJob *job, SEpSet *epSet) {  
+  if (epSet->numOfEps >= SCH_MAX_CONDIDATE_EP_NUM) {
+    return TSDB_CODE_SUCCESS;
   }
+
+  if (SCH_HAS_QNODE_IN_CLUSTER(schMgmt.cfg.clusterType)) {
+    SCH_ERR_RET(catalogGetQnodeList(job->catalog, job->rpc, job->mgmtEpSet, epSet));
+  } else {
+    for (int32_t i = 0; i < job->dataSrcEps.numOfEps; ++i) {
+      strncpy(epSet->fqdn[epSet->numOfEps], job->dataSrcEps.fqdn[i], sizeof(job->dataSrcEps.fqdn[i]));
+      epSet->port[epSet->numOfEps] = job->dataSrcEps.port[i];
+      
+      ++epSet->numOfEps;
+    }
+  }
+
+  return TSDB_CODE_SUCCESS;
+}
+
+
+int32_t schPushTaskToExecList(SQueryJob *job, SQueryTask *task) {
+  if (0 != taosHashPut(job->execTasks, &task->taskId, sizeof(task->taskId), &task, POINTER_BYTES)) {
+    qError("taosHashPut failed");
+    SCH_ERR_RET(TSDB_CODE_QRY_OUT_OF_MEMORY);
+  }
+
+  return TSDB_CODE_SUCCESS;
+}
+
+int32_t schMoveTaskToSuccList(SQueryJob *job, SQueryTask *task, bool *moved) {
+  if (0 != taosHashRemove(job->execTasks, &task->taskId, sizeof(task->taskId))) {
+    qWarn("remove task[%"PRIx64"] from execTasks failed", task->taskId);
+    return TSDB_CODE_SUCCESS;
+  }
+
+  if (0 != taosHashPut(job->execTasks, &task->taskId, sizeof(task->taskId), &task, POINTER_BYTES)) {
+    qError("taosHashPut failed");
+    SCH_ERR_RET(TSDB_CODE_QRY_OUT_OF_MEMORY);
+  }
+
+  *moved = true;
+  
+  return TSDB_CODE_SUCCESS;
+}
+
+
+int32_t schAsyncSendMsg(SQueryJob *job, SQueryTask *task, int32_t msgType) {
+  int32_t msgSize = 0;
+  void *msg = NULL;
+  
+  switch (msgType) {
+    case TSDB_MSG_TYPE_QUERY: {
+      if (NULL == task->msg) {
+        qError("query msg is NULL");
+        SCH_ERR_RET(TSDB_CODE_SCH_INTERNAL_ERROR);
+      }
+
+      int32_t len = strlen(task->msg);
+      msgSize = sizeof(SSchedulerQueryMsg) + len;
+      msg = calloc(1, msgSize);
+      if (NULL == msg) {
+        qError("calloc %d failed", msgSize);
+        SCH_ERR_RET(TSDB_CODE_QRY_OUT_OF_MEMORY);
+      }
+
+      SSchedulerQueryMsg *pMsg = msg;
+      pMsg->queryId = job->queryId;
+      pMsg->taskId = task->taskId;
+      pMsg->contentLen = len;
+      memcpy(pMsg->msg, task->msg, len);
+      break;
+    }
+    case TSDB_MSG_TYPE_RSP_READY: {
+      msgSize = sizeof(SSchedulerReadyMsg);
+      msg = calloc(1, msgSize);
+      if (NULL == msg) {
+        qError("calloc %d failed", msgSize);
+        SCH_ERR_RET(TSDB_CODE_QRY_OUT_OF_MEMORY);
+      }
+
+      SSchedulerReadyMsg *pMsg = msg;
+      pMsg->queryId = job->queryId;
+      pMsg->taskId = task->taskId;      
+      break;
+    }
+    case TSDB_MSG_TYPE_FETCH: {
+      msgSize = sizeof(SSchedulerFetchMsg);
+      msg = calloc(1, msgSize);
+      if (NULL == msg) {
+        qError("calloc %d failed", msgSize);
+        SCH_ERR_RET(TSDB_CODE_QRY_OUT_OF_MEMORY);
+      }
+    
+      SSchedulerFetchMsg *pMsg = msg;
+      pMsg->queryId = job->queryId;
+      pMsg->taskId = task->taskId;      
+      break;
+    }
+    default:
+      qError("unknown msg type:%d", msgType);
+      break;
+  }
+
+  //TODO SEND MSG
+
+  return TSDB_CODE_SUCCESS;
+}
+
+int32_t schTaskCheckAndSetRetry(SQueryJob *job, SQueryTask *task, int32_t errCode, bool *needRetry) {
+  // TODO set retry or not based on task type/errCode/retry times/job status/available eps...
+  // TODO if needRetry, set task retry info
+
+  *needRetry = false;
+
+  return TSDB_CODE_SUCCESS;
+}
+
+
+int32_t schFetchFromRemote(SQueryJob *job) {
+  int32_t code = 0;
+  
+  if (atomic_val_compare_exchange_32(&job->remoteFetch, 0, 1) != 0) {
+    qInfo("prior fetching not finished");
+    return TSDB_CODE_SUCCESS;
+  }
+
+  SCH_ERR_JRET(schAsyncSendMsg(job, NULL, TSDB_MSG_TYPE_FETCH));
+
+  return TSDB_CODE_SUCCESS;
+  
+_return:
+  atomic_val_compare_exchange_32(&job->remoteFetch, 1, 0);
+
+  return code;
+}
+
+
+int32_t schProcessOnJobSuccess(SQueryJob *job) {
+  job->status = SCH_STATUS_SUCCEED;
+  
+  if (job->userFetch) {
+    SCH_ERR_RET(schFetchFromRemote(job));
+  }
+
+  return TSDB_CODE_SUCCESS;
+}
+
+int32_t schProcessOnJobFailure(SQueryJob *job) {
+  job->status = SCH_STATUS_FAILED;
+
+  atomic_val_compare_exchange_32(&job->remoteFetch, 1, 0);
+
+  if (job->userFetch) {
+    tsem_post(&job->rspSem);
+  }
+
+  return TSDB_CODE_SUCCESS;
+}
+
+int32_t schProcessOnDataFetched(SQueryJob *job) {
+  atomic_val_compare_exchange_32(&job->remoteFetch, 1, 0);
+
+  tsem_post(&job->rspSem);
+}
+
+
+int32_t schProcessOnTaskSuccess(SQueryJob *job, SQueryTask *task) {
+  bool moved = false;
+  
+  SCH_ERR_RET(schMoveTaskToSuccList(job, task, &moved));
+  if (!moved) {
+    SCH_TASK_ERR_LOG("task may already moved, status:%d", task->status);
+    return TSDB_CODE_SUCCESS;
+  }
+
+  task->status = SCH_STATUS_SUCCEED;
+  
+  int32_t parentNum = (int32_t)taosArrayGetSize(task->parents);
+  if (parentNum == 0) {
+    if (task->plan->level != 0) {
+      qError("level error");
+      SCH_ERR_RET(TSDB_CODE_QRY_INVALID_INPUT);
+    }
+
+    strncpy(job->resEp.fqdn, task->execAddr.fqdn, sizeof(job->resEp.fqdn));
+    job->resEp.port = task->execAddr.port;
+
+    SCH_ERR_RET(schProcessOnJobSuccess(job));
+
+    return TSDB_CODE_SUCCESS;
+  }
+
+  if (SCH_IS_DATA_SRC_TASK(task) && job->dataSrcEps.numOfEps < SCH_MAX_CONDIDATE_EP_NUM) {
+    strncpy(job->dataSrcEps.fqdn[job->dataSrcEps.numOfEps], task->execAddr.fqdn, sizeof(task->execAddr.fqdn));
+    job->dataSrcEps.port[job->dataSrcEps.numOfEps] = task->execAddr.port;
+
+    ++job->dataSrcEps.numOfEps;
+  }
+
+  for (int32_t i = 0; i < parentNum; ++i) {
+    SQueryTask *par = taosArrayGet(task->parents, i);
+
+    ++par->childReady;
+
+    SCH_ERR_RET(qSetSubplanExecutionNode(par->plan, task->plan->id.templateId, &task->execAddr));
+    
+    if (SCH_TASK_READY_TO_LUNCH(par)) {
+      SCH_ERR_RET(schLaunchTask(job, task));
+    }
+  }
+
+  return TSDB_CODE_SUCCESS;
+}
+
+int32_t schProcessOnTaskFailure(SQueryJob *job, SQueryTask *task, int32_t errCode) {
+  bool needRetry = false;
+  SCH_ERR_RET(schTaskCheckAndSetRetry(job, task, errCode, &needRetry));
+  
+  if (!needRetry) {
+    SCH_TASK_ERR_LOG("task failed[%x], no more retry", errCode);
+    
+    job->status = SCH_STATUS_FAILED;
+    SCH_ERR_RET(schProcessOnJobFailure(job));
+
+    return TSDB_CODE_SUCCESS;
+  }
+
+  SCH_ERR_RET(schLaunchTask(job, task));
+
+  return TSDB_CODE_SUCCESS;
+}
+
+int32_t schHandleRspMsg(SQueryJob *job, SQueryTask *task, int32_t msgType, int32_t rspCode) {
+  int32_t code = 0;
+  
+  switch (msgType) {
+    case TSDB_MSG_TYPE_QUERY:
+      if (rspCode != TSDB_CODE_SUCCESS) {
+        SCH_ERR_JRET(schProcessOnTaskFailure(job, task, rspCode));
+      } else {
+        code = schAsyncSendMsg(job, task, TSDB_MSG_TYPE_RSP_READY);
+        if (code) {
+          goto _task_error;
+        }
+      }
+      break;
+    case TSDB_MSG_TYPE_RSP_READY:
+      if (rspCode != TSDB_CODE_SUCCESS) {
+        SCH_ERR_JRET(schProcessOnTaskFailure(job, task, rspCode));
+      } else {
+        code = schProcessOnTaskSuccess(job, task);
+        if (code) {
+          goto _task_error;
+        }        
+      }
+      break;
+    case TSDB_MSG_TYPE_FETCH:
+      SCH_ERR_JRET(rspCode);
+      SCH_ERR_JRET(schProcessOnDataFetched(job));
+      break;
+    default:
+      qError("unknown msg type:%d received", msgType);
+      return TSDB_CODE_QRY_INVALID_INPUT;
+  }
+
+  return TSDB_CODE_SUCCESS;
+
+_task_error:
+  SCH_ERR_JRET(schProcessOnTaskFailure(job, task, code));
+  return TSDB_CODE_SUCCESS;
+
+_return:
+  code = schProcessOnJobFailure(job);
+  return code;
+}
+
+
+
+
+int32_t schLaunchTask(SQueryJob *job, SQueryTask *task) {
+  SSubplan *plan = task->plan;
+  
+  SCH_ERR_RET(qSubPlanToString(plan, &task->msg));
+  if (plan->execEpSet.numOfEps <= 0) {
+    SCH_ERR_RET(schAvailableEpSet(job, &plan->execEpSet));
+  }
+  
+  SCH_ERR_RET(schAsyncSendMsg(job, task, TSDB_MSG_TYPE_QUERY));
+
+  SCH_ERR_RET(schPushTaskToExecList(job, task));
+
+  task->status = SCH_STATUS_EXECUTING;
+
+  return TSDB_CODE_SUCCESS;
+}
+
+int32_t schLaunchJob(SQueryJob *job) {
+  SQueryLevel *level = taosArrayGet(job->levels, job->levelIdx);
+  for (int32_t i = 0; i < level->taskNum; ++i) {
+    SQueryTask *task = taosArrayGet(level->subTasks, i);
+    SCH_ERR_RET(schLaunchTask(job, task));
+  }
+
+  job->status = SCH_STATUS_EXECUTING;
+  
+  return TSDB_CODE_SUCCESS;
 }
 
 
@@ -141,12 +540,16 @@ int32_t schedulerInit(SSchedulerCfg *cfg) {
     SCH_ERR_LRET(TSDB_CODE_QRY_OUT_OF_MEMORY, "init %d schduler jobs failed", SCHEDULE_DEFAULT_JOB_NUMBER);
   }
 
+  if (cfg) {
+    schMgmt.cfg = *cfg;
+  }
+
   return TSDB_CODE_SUCCESS;
 }
 
 
-int32_t scheduleQueryJob(SQueryDag* pDag, void** pJob) {
-  if (NULL == pDag || NULL == pDag->pSubplans || NULL == pJob) {
+int32_t scheduleQueryJob(struct SCatalog *pCatalog, void *pRpc, const SEpSet* pMgmtEps, SQueryDag* pDag, void** pJob) {
+  if (NULL == pCatalog || NULL == pRpc || NULL == pMgmtEps || NULL == pDag || NULL == pDag->pSubplans || NULL == pJob) {
     SCH_ERR_RET(TSDB_CODE_QRY_INVALID_INPUT);
   }
 
@@ -156,12 +559,37 @@ int32_t scheduleQueryJob(SQueryDag* pDag, void** pJob) {
     SCH_ERR_RET(TSDB_CODE_QRY_OUT_OF_MEMORY);
   }
 
+  job->catalog = pCatalog;
+  job->rpc = pRpc;
+  job->mgmtEpSet = (SEpSet *)pMgmtEps;
+
   SCH_ERR_JRET(schValidateAndBuildJob(pDag, job));
 
-  SCH_ERR_JRET(schJobExecute(job));
+  job->execTasks = taosHashInit(pDag->numOfSubplans, taosGetDefaultHashFunction(TSDB_DATA_TYPE_UBIGINT), false, HASH_ENTRY_LOCK);
+  if (NULL == job->execTasks) {
+    qError("taosHashInit %d failed", pDag->numOfSubplans);
+    SCH_ERR_JRET(TSDB_CODE_QRY_OUT_OF_MEMORY);
+  }
+
+  job->succTasks = taosHashInit(pDag->numOfSubplans, taosGetDefaultHashFunction(TSDB_DATA_TYPE_UBIGINT), false, HASH_ENTRY_LOCK);
+  if (NULL == job->succTasks) {
+    qError("taosHashInit %d failed", pDag->numOfSubplans);
+    SCH_ERR_JRET(TSDB_CODE_QRY_OUT_OF_MEMORY);
+  }
+
+  tsem_init(&job->rspSem, 0, 0);
+  
+  if (0 != taosHashPut(schMgmt.Jobs, &job->queryId, sizeof(job->queryId), &job, POINTER_BYTES)) {
+    qError("taosHashPut queryId:%"PRIx64" failed", job->queryId);
+    SCH_ERR_JRET(TSDB_CODE_SCH_INTERNAL_ERROR);
+  }
+
+  job->status = SCH_STATUS_NOT_START;
+  
+  SCH_ERR_JRET(schLaunchJob(job));
 
   *(SQueryJob **)pJob = job;
-  
+
   return TSDB_CODE_SUCCESS;
 
 _return:
@@ -172,17 +600,64 @@ _return:
   SCH_RET(code);
 }
 
-int32_t scheduleFetchRows(void *pJob, void *data);
+int32_t scheduleFetchRows(void *pJob, void **data) {
+  if (NULL == pJob || NULL == data) {
+    return TSDB_CODE_QRY_INVALID_INPUT;
+  }
 
-int32_t scheduleCancelJob(void *pJob);
+  SQueryJob *job = pJob;
+  int32_t code = 0;
+
+  if (atomic_val_compare_exchange_32(&job->userFetch, 0, 1) != 0) {
+    qError("prior fetching not finished");
+    return TSDB_CODE_QRY_APP_ERROR;
+  }
+
+  if (job->status == SCH_STATUS_SUCCEED) {
+    SCH_ERR_JRET(schFetchFromRemote(job));
+  }
+
+  tsem_wait(&job->rspSem);
+
+  *data = job->res;
+  job->res = NULL;
+
+_return:
+  atomic_val_compare_exchange_32(&job->userFetch, 1, 0);
+
+  return code;
+}
+
+int32_t scheduleCancelJob(void *pJob) {
+  //TODO
+
+  return TSDB_CODE_SUCCESS;
+}
 
 void scheduleFreeJob(void *pJob) {
+  if (NULL == pJob) {
+    return;
+  }
 
+  SQueryJob *job = pJob;
+
+  if (job->status > 0) {
+    if (0 != taosHashRemove(schMgmt.Jobs, &job->queryId, sizeof(job->queryId))) {
+      qError("remove job:%"PRIx64"from mgmt failed", job->queryId); // maybe already freed
+      return;
+    }
+
+    if (job->status == SCH_STATUS_EXECUTING) {
+      scheduleCancelJob(pJob);
+    }
+  }
+  
+  //TODO free job
 }
 
 void schedulerDestroy(void) {
   if (schMgmt.Jobs) {
-    taosHashCleanup(schMgmt.Jobs); //TBD
+    taosHashCleanup(schMgmt.Jobs); //TODO
     schMgmt.Jobs = NULL;
   }
 }
diff --git a/source/util/src/terror.c b/source/util/src/terror.c
index 3e374b344b..ffc59c5d69 100644
--- a/source/util/src/terror.c
+++ b/source/util/src/terror.c
@@ -499,6 +499,7 @@ TAOS_DEFINE_ERROR(TSDB_CODE_CTG_SYS_ERROR,                "catalog system error"
 
 //scheduler
 TAOS_DEFINE_ERROR(TSDB_CODE_SCH_STATUS_ERROR,             "scheduler status error")
+TAOS_DEFINE_ERROR(TSDB_CODE_SCH_INTERNAL_ERROR,           "scheduler internal error")
 
 
 #ifdef TAOS_ERROR_C