diff --git a/src/client/src/tscSubquery.c b/src/client/src/tscSubquery.c
index 422d07ccde76b7358513d06aa942191d71478410..75307087b19a163af4a51a7d58bdfbd80bf7c2ca 100644
--- a/src/client/src/tscSubquery.c
+++ b/src/client/src/tscSubquery.c
@@ -15,8 +15,9 @@
 #define _GNU_SOURCE
 
 #include "os.h"
-
 #include "texpr.h"
+
+#include "tsched.h"
 #include "qTsbuf.h"
 #include "tcompare.h"
 #include "tscLog.h"
@@ -2423,6 +2424,26 @@ int32_t tscHandleFirstRoundStableQuery(SSqlObj *pSql) {
   return terrno;
 }
 
+typedef struct SPair {
+  int32_t first;
+  int32_t second;
+} SPair;
+
+static void doSendQueryReqs(SSchedMsg* pSchedMsg) {
+  SSqlObj* pSql = pSchedMsg->ahandle;
+  SPair* p = pSchedMsg->msg;
+
+  for(int32_t i = p->first; i < p->second; ++i) {
+    SSqlObj* pSub = pSql->pSubs[i];
+    SRetrieveSupport* pSupport = pSub->param;
+
+    tscDebug("0x%"PRIx64" sub:0x%"PRIx64" launch subquery, orderOfSub:%d.", pSql->self, pSub->self, pSupport->subqueryIndex);
+    tscProcessSql(pSub);
+  }
+
+  tfree(p);
+}
+
 int32_t tscHandleMasterSTableQuery(SSqlObj *pSql) {
   SSqlRes *pRes = &pSql->res;
   SSqlCmd *pCmd = &pSql->cmd;
@@ -2546,13 +2567,33 @@ int32_t tscHandleMasterSTableQuery(SSqlObj *pSql) {
     doCleanupSubqueries(pSql, i);
     return pRes->code;
   }
-  
-  for(int32_t j = 0; j < pState->numOfSub; ++j) {
-    SSqlObj* pSub = pSql->pSubs[j];
-    SRetrieveSupport* pSupport = pSub->param;
-    
-    tscDebug("0x%"PRIx64" sub:%p launch subquery, orderOfSub:%d.", pSql->self, pSub, pSupport->subqueryIndex);
-    tscProcessSql(pSub);
+
+  // concurrently sent the query requests.
+  const int32_t MAX_REQUEST_PER_TASK = 8;
+
+  int32_t numOfTasks = (pState->numOfSub + MAX_REQUEST_PER_TASK - 1)/MAX_REQUEST_PER_TASK;
+  assert(numOfTasks >= 1);
+
+  int32_t num = (pState->numOfSub/numOfTasks) + 1;
+  tscDebug("0x%"PRIx64 " query will be sent by %d threads", pSql->self, numOfTasks);
+
+  for(int32_t j = 0; j < numOfTasks; ++j) {
+    SSchedMsg schedMsg = {0};
+    schedMsg.fp      = doSendQueryReqs;
+    schedMsg.ahandle = (void*)pSql;
+
+    schedMsg.thandle = NULL;
+    SPair* p = calloc(1, sizeof(SPair));
+    p->first  = j * num;
+
+    if (j == numOfTasks - 1) {
+      p->second = pState->numOfSub;
+    } else {
+      p->second = (j + 1) * num;
+    }
+
+    schedMsg.msg = p;
+    taosScheduleTask(tscQhandle, &schedMsg);
   }
 
   return TSDB_CODE_SUCCESS;