diff --git a/source/common/src/tglobal.c b/source/common/src/tglobal.c
index bacafee34992e2b9d86028bde67d55373c167caa..74471eca9ae3db6fd1b8c3cbdd7312220dd02dd9 100644
--- a/source/common/src/tglobal.c
+++ b/source/common/src/tglobal.c
@@ -111,7 +111,7 @@ int32_t tmqMaxTopicNum = 20;
 int32_t tsQueryPolicy = 1;
 int32_t tsQueryRspPolicy = 0;
 int64_t tsQueryMaxConcurrentTables = 200;  // unit is TSDB_TABLE_NUM_UNIT
-bool    tsEnableQueryHb = false;
+bool    tsEnableQueryHb = true;
 bool    tsEnableScience = false;  // on taos-cli show float and doulbe with scientific notation if true
 bool    tsTtlChangeOnWrite = false; // ttl delete time changes on last write if true
 int32_t tsQuerySmaOptimize = 0;
diff --git a/source/libs/scheduler/inc/schInt.h b/source/libs/scheduler/inc/schInt.h
index 7840fe2017a6f384e70f1553105c7293a4abb2d7..aecf3d5d916681687986ec1771d7f02e79304a8b 100644
--- a/source/libs/scheduler/inc/schInt.h
+++ b/source/libs/scheduler/inc/schInt.h
@@ -57,7 +57,7 @@ typedef enum {
 #define SCHEDULE_DEFAULT_POLICY             SCH_LOAD_SEQ
 #define SCHEDULE_DEFAULT_MAX_NODE_NUM       20
 
-#define SCH_DEFAULT_TASK_TIMEOUT_USEC 60000000
+#define SCH_DEFAULT_TASK_TIMEOUT_USEC 5000000
 #define SCH_MAX_TASK_TIMEOUT_USEC     300000000
 #define SCH_DEFAULT_MAX_RETRY_NUM     6
 #define SCH_MIN_AYSNC_EXEC_NUM        3
@@ -239,7 +239,7 @@ typedef struct SSchTask {
   int32_t         lastMsgType;     // last sent msg type
   int64_t         timeoutUsec;     // task timeout useconds before reschedule
   SQueryNodeAddr  succeedAddr;     // task executed success node address
-  int8_t          candidateIdx;    // current try condidation index
+  int32_t         candidateIdx;    // current try condidation index
   SArray         *candidateAddrs;  // condidate node addresses, element is SQueryNodeAddr
   SHashObj       *execNodes;       // all tried node for current task, element is SSchNodeInfo
   SSchTaskProfile profile;         // task execution profile
diff --git a/source/libs/scheduler/src/schTask.c b/source/libs/scheduler/src/schTask.c
index 78e28bce4958f91a6802ea93798886d02c34af23..41357b2a41b256b43a2466ceed7ea15ad43bed2c 100644
--- a/source/libs/scheduler/src/schTask.c
+++ b/source/libs/scheduler/src/schTask.c
@@ -745,7 +745,6 @@ int32_t schSetTaskCandidateAddrs(SSchJob *pJob, SSchTask *pTask) {
     return TSDB_CODE_SUCCESS;
   }
 
-  pTask->candidateIdx = 0;
   pTask->candidateAddrs = taosArrayInit(SCHEDULE_DEFAULT_MAX_NODE_NUM, sizeof(SQueryNodeAddr));
   if (NULL == pTask->candidateAddrs) {
     SCH_TASK_ELOG("taosArrayInit %d condidate addrs failed", SCHEDULE_DEFAULT_MAX_NODE_NUM);
@@ -770,6 +769,8 @@ int32_t schSetTaskCandidateAddrs(SSchJob *pJob, SSchTask *pTask) {
 
   SCH_ERR_RET(schSetAddrsFromNodeList(pJob, pTask));
 
+  pTask->candidateIdx = abs(taosRand() % taosArrayGetSize(pTask->candidateAddrs));
+
   /*
     for (int32_t i = 0; i < job->dataSrcEps.numOfEps && addNum < SCH_MAX_CANDIDATE_EP_NUM; ++i) {
       strncpy(epSet->fqdn[epSet->numOfEps], job->dataSrcEps.fqdn[i], sizeof(job->dataSrcEps.fqdn[i]));