diff --git a/src/common/src/tglobal.c b/src/common/src/tglobal.c
index 4b5392257ffa072c53c4332733518c8f1f68f8bd..17eb5714e0272bcebe21de84d938f94708b7c4d9 100644
--- a/src/common/src/tglobal.c
+++ b/src/common/src/tglobal.c
@@ -206,7 +206,7 @@ int32_t tsNumOfLogLines = 10000000;
 int32_t mDebugFlag = 131;
 int32_t sdbDebugFlag = 131;
 int32_t dDebugFlag = 135;
-int32_t vDebugFlag = 131;
+int32_t vDebugFlag = 135;
 int32_t cDebugFlag = 131;
 int32_t jniDebugFlag = 131;
 int32_t odbcDebugFlag = 131;
diff --git a/src/cq/src/cqMain.c b/src/cq/src/cqMain.c
index 3968d5b8c9dfbb53ad04179e0451fc9aab76980e..e278c3a7ccd145585b70d3488abaf1a9dceab571 100644
--- a/src/cq/src/cqMain.c
+++ b/src/cq/src/cqMain.c
@@ -161,7 +161,7 @@ void cqStop(void *handle) {
     return;
   }
   SCqContext *pContext = handle;
-  cInfo("vgId:%d, stop all CQs", pContext->vgId);
+  cDebug("vgId:%d, stop all CQs", pContext->vgId);
   if (pContext->dbConn == NULL || pContext->master == 0) return;
 
   pthread_mutex_lock(&pContext->mutex);
diff --git a/src/inc/taoserror.h b/src/inc/taoserror.h
index e0d7e018434f15d96fe559440ba6b07f027cd930..be33262f7f75f20485c977c3b3a7378a6021481a 100644
--- a/src/inc/taoserror.h
+++ b/src/inc/taoserror.h
@@ -206,9 +206,10 @@ TAOS_DEFINE_ERROR(TSDB_CODE_VND_NO_SUCH_FILE_OR_DIR,      0, 0x0507, "Missing da
 TAOS_DEFINE_ERROR(TSDB_CODE_VND_OUT_OF_MEMORY,            0, 0x0508, "Out of memory")
 TAOS_DEFINE_ERROR(TSDB_CODE_VND_APP_ERROR,                0, 0x0509, "Unexpected generic error in vnode")
 TAOS_DEFINE_ERROR(TSDB_CODE_VND_INVALID_VRESION_FILE,     0, 0x050A, "Invalid version file")
-TAOS_DEFINE_ERROR(TSDB_CODE_VND_IS_FULL,                  0, 0x050B, "Vnode memory is full because commit failed")
+TAOS_DEFINE_ERROR(TSDB_CODE_VND_IS_FULL,                  0, 0x050B, "Database memory is full for commit failed")
+TAOS_DEFINE_ERROR(TSDB_CODE_VND_IS_FLOWCTRL,              0, 0x050C, "Database memory is full for waiting commit")
 TAOS_DEFINE_ERROR(TSDB_CODE_VND_NOT_SYNCED,               0, 0x0511, "Database suspended")
-TAOS_DEFINE_ERROR(TSDB_CODE_VND_NO_WRITE_AUTH,            0, 0x0512, "Write operation denied")
+TAOS_DEFINE_ERROR(TSDB_CODE_VND_NO_WRITE_AUTH,            0, 0x0512, "Database write operation denied")
 TAOS_DEFINE_ERROR(TSDB_CODE_VND_SYNCING,                  0, 0x0513, "Database is syncing")
 
 // tsdb
diff --git a/src/mnode/src/mnodeSdb.c b/src/mnode/src/mnodeSdb.c
index 48342b38138a560f3293de2ea43e8d66e595252d..6cc4e097350783a93300c46adbd5f68faf43e143 100644
--- a/src/mnode/src/mnodeSdb.c
+++ b/src/mnode/src/mnodeSdb.c
@@ -35,7 +35,7 @@
 #include "mnodeSdb.h"
 
 #define SDB_TABLE_LEN 12
-#define MAX_QUEUED_MSG_NUM 1024
+#define MAX_QUEUED_MSG_NUM 10000
 
 typedef enum {
   SDB_ACTION_INSERT = 0,
diff --git a/src/vnode/src/vnodeRead.c b/src/vnode/src/vnodeRead.c
index 03d1272771d599e9115896148007c9b1fe310151..7ad97396c2df2b105056861e5c2916de92c7d8d9 100644
--- a/src/vnode/src/vnodeRead.c
+++ b/src/vnode/src/vnodeRead.c
@@ -133,7 +133,7 @@ static int32_t vnodePutItemIntoReadQueue(SVnodeObj *pVnode, void **qhandle, void
 
   int32_t code = vnodeWriteToRQueue(pVnode, qhandle, 0, TAOS_QTYPE_QUERY, &rpcMsg);
   if (code == TSDB_CODE_SUCCESS) {
-    vDebug("QInfo:%p add to vread queue for exec query", *qhandle);
+    vTrace("QInfo:%p add to vread queue for exec query", *qhandle);
   }
 
   return code;
@@ -164,7 +164,7 @@ static int32_t vnodeDumpQueryResult(SRspRet *pRet, void *pVnode, void **handle,
       }
     } else {
       *freeHandle = true;
-      vDebug("QInfo:%p exec completed, free handle:%d", *handle, *freeHandle);
+      vTrace("QInfo:%p exec completed, free handle:%d", *handle, *freeHandle);
     }
   } else {
     SRetrieveTableRsp *pRsp = (SRetrieveTableRsp *)rpcMallocCont(sizeof(SRetrieveTableRsp));
@@ -266,7 +266,7 @@ static int32_t vnodeProcessQueryMsg(SVnodeObj *pVnode, SVReadMsg *pRead) {
     }
 
     if (handle != NULL) {
-      vDebug("vgId:%d, QInfo:%p, dnode query msg disposed, create qhandle and returns to app", vgId, *handle);
+      vTrace("vgId:%d, QInfo:%p, dnode query msg disposed, create qhandle and returns to app", vgId, *handle);
       code = vnodePutItemIntoReadQueue(pVnode, handle, pRead->rpcHandle);
       if (code != TSDB_CODE_SUCCESS) {
         pRsp->code = code;
@@ -278,7 +278,7 @@ static int32_t vnodeProcessQueryMsg(SVnodeObj *pVnode, SVReadMsg *pRead) {
     assert(pCont != NULL);
     void **qhandle = (void **)pRead->qhandle;
 
-    vDebug("vgId:%d, QInfo:%p, dnode continues to exec query", pVnode->vgId, *qhandle);
+    vTrace("vgId:%d, QInfo:%p, dnode continues to exec query", pVnode->vgId, *qhandle);
 
     // In the retrieve blocking model, only 50% CPU will be used in query processing
     if (tsHalfCoresForQuery) {
@@ -294,7 +294,7 @@ static int32_t vnodeProcessQueryMsg(SVnodeObj *pVnode, SVReadMsg *pRead) {
         pRead->rpcHandle = qGetResultRetrieveMsg(*qhandle);
         assert(pRead->rpcHandle != NULL);
 
-        vDebug("vgId:%d, QInfo:%p, start to build retrieval rsp after query paused, %p", pVnode->vgId, *qhandle,
+        vTrace("vgId:%d, QInfo:%p, start to build retrieval rsp after query paused, %p", pVnode->vgId, *qhandle,
                pRead->rpcHandle);
 
         // set the real rsp error code
@@ -327,7 +327,7 @@ static int32_t vnodeProcessFetchMsg(SVnodeObj *pVnode, SVReadMsg *pRead) {
   pRetrieve->free = htons(pRetrieve->free);
   pRetrieve->qhandle = htobe64(pRetrieve->qhandle);
 
-  vDebug("vgId:%d, QInfo:%p, retrieve msg is disposed, free:%d, conn:%p", pVnode->vgId, (void *)pRetrieve->qhandle,
+  vTrace("vgId:%d, QInfo:%p, retrieve msg is disposed, free:%d, conn:%p", pVnode->vgId, (void *)pRetrieve->qhandle,
          pRetrieve->free, pRead->rpcHandle);
 
   memset(pRet, 0, sizeof(SRspRet));
@@ -410,6 +410,6 @@ int32_t vnodeNotifyCurrentQhandle(void *handle, void *qhandle, int32_t vgId) {
   pMsg->header.vgId = htonl(vgId);
   pMsg->header.contLen = htonl(sizeof(SRetrieveTableMsg));
 
-  vDebug("QInfo:%p register qhandle to connect:%p", qhandle, handle);
+  vTrace("QInfo:%p register qhandle to connect:%p", qhandle, handle);
   return rpcReportProgress(handle, (char *)pMsg, sizeof(SRetrieveTableMsg));
 }
diff --git a/src/vnode/src/vnodeWrite.c b/src/vnode/src/vnodeWrite.c
index b23eeb207d32b079d80a18d38874875f8d0275f4..cd462f7f0a1e37b514e9ffd3a890880918a149d6 100644
--- a/src/vnode/src/vnodeWrite.c
+++ b/src/vnode/src/vnodeWrite.c
@@ -23,7 +23,7 @@
 #include "dnode.h"
 #include "vnodeStatus.h"
 
-#define MAX_QUEUED_MSG_NUM 1024
+#define MAX_QUEUED_MSG_NUM 10000
 
 extern void *  tsDnodeTmr;
 static int32_t (*vnodeProcessWriteMsgFp[TSDB_MSG_TYPE_MAX])(SVnodeObj *, void *pCont, SRspRet *);
@@ -271,6 +271,8 @@ static void vnodeFlowCtrlMsgToWQueue(void *param, void *tmrId) {
   SVnodeObj * pVnode = pWrite->pVnode;
   int32_t     code = TSDB_CODE_VND_SYNCING;
 
+  if (pVnode->flowctrlLevel <= 0) code = TSDB_CODE_VND_IS_FLOWCTRL;
+
   pWrite->processedCount++;
   if (pWrite->processedCount > 100) {
     vError("vgId:%d, msg:%p, failed to process since %s, retry:%d", pVnode->vgId, pWrite, tstrerror(code),
@@ -290,8 +292,10 @@ static void vnodeFlowCtrlMsgToWQueue(void *param, void *tmrId) {
 
 static int32_t vnodePerformFlowCtrl(SVWriteMsg *pWrite) {
   SVnodeObj *pVnode = pWrite->pVnode;
-  if (pVnode->flowctrlLevel <= 0) return 0;
-  if (pWrite->qtype != TAOS_QTYPE_RPC) return 0;
+  if (pVnode->queuedWMsg < MAX_QUEUED_MSG_NUM) {
+    if (pVnode->flowctrlLevel <= 0) return 0;
+    if (pWrite->qtype != TAOS_QTYPE_RPC) return 0;
+  }
 
   if (tsFlowCtrl == 0) {
     int32_t ms = pow(2, pVnode->flowctrlLevel + 2);