diff --git a/src/sync/inc/syncInt.h b/src/sync/inc/syncInt.h
index aacd72e930d95b2721dfe28e92abba5e16654d38..7dbb1985d4cd6e68b7009004a563f66ab63a6697 100644
--- a/src/sync/inc/syncInt.h
+++ b/src/sync/inc/syncInt.h
@@ -172,6 +172,7 @@ typedef struct SSyncNode {
 // sync module global
 extern int32_t tsSyncNum;
 extern char    tsNodeFqdn[TSDB_FQDN_LEN];
+extern char *  syncStatus[];
 
 void *syncRetrieveData(void *param);
 void *syncRestoreData(void *param);
diff --git a/src/sync/src/syncMain.c b/src/sync/src/syncMain.c
index dd759ed9d4d61e53dc4e0b53544e9c07bfa277bc..a68f0b7bbbf429ba2e96c36e23803c2398b27deb 100644
--- a/src/sync/src/syncMain.c
+++ b/src/sync/src/syncMain.c
@@ -73,6 +73,14 @@ char* syncRole[] = {
   "master"
 };
 
+char *syncStatus[] = {
+  "init",
+  "start",
+  "file",
+  "cache",
+  "invalid"
+};
+
 typedef enum {
   SYNC_STATUS_BROADCAST,
   SYNC_STATUS_BROADCAST_RSP,
@@ -282,7 +290,7 @@ void syncStop(int64_t rid) {
   pPeer = pNode->peerInfo[TAOS_SYNC_MAX_REPLICA];
   if (pPeer) syncRemovePeer(pPeer);
 
-  pthread_mutex_unlock(&(pNode->mutex));
+  pthread_mutex_unlock(&pNode->mutex);
 
   taosReleaseRef(tsSyncRefId, rid);
   taosRemoveRef(tsSyncRefId, rid);
@@ -350,7 +358,7 @@ int32_t syncReconfig(int64_t rid, const SSyncCfg *pNewCfg) {
     (*pNode->notifyRole)(pNode->vgId, nodeRole);
   }
 
-  pthread_mutex_unlock(&(pNode->mutex));
+  pthread_mutex_unlock(&pNode->mutex);
 
   sInfo("vgId:%d, %d replicas are configured, quorum:%d", pNode->vgId, pNode->replica, pNode->quorum);
   syncBroadcastStatus(pNode);
@@ -423,7 +431,7 @@ void syncRecover(int64_t rid) {
     }
   }
 
-  pthread_mutex_unlock(&(pNode->mutex));
+  pthread_mutex_unlock(&pNode->mutex);
 
   taosReleaseRef(tsSyncRefId, rid);
 }
@@ -498,6 +506,8 @@ int32_t syncDecPeerRef(SSyncPeer *pPeer) {
 }
 
 static void syncClosePeerConn(SSyncPeer *pPeer) {
+  sDebug("%s, pfd:%d sfd:%d will be closed", pPeer->id, pPeer->peerFd, pPeer->syncFd);
+
   taosTmrStopA(&pPeer->timer);
   taosClose(pPeer->syncFd);
   if (pPeer->peerFd >= 0) {
@@ -751,7 +761,7 @@ static void syncCheckRole(SSyncPeer *pPeer, SPeerStatus* peersStatus, int8_t new
       sDebug("vgId:%d, choose master", pNode->vgId);
       syncChooseMaster(pNode);
     } else {
-      sDebug("vgId:%d, version inconsistent, cannot choose master", pNode->vgId);
+      sDebug("vgId:%d, cannot choose master since roles inconsistent", pNode->vgId);
     }
   }
 
@@ -770,11 +780,12 @@ static void syncCheckRole(SSyncPeer *pPeer, SPeerStatus* peersStatus, int8_t new
 }
 
 static void syncRestartPeer(SSyncPeer *pPeer) {
-  sDebug("%s, restart peer connection", pPeer->id);
+  sDebug("%s, restart peer connection, last sstatus:%s", pPeer->id, syncStatus[pPeer->sstatus]);
 
   syncClosePeerConn(pPeer);
 
   pPeer->sstatus = TAOS_SYNC_STATUS_INIT;
+  sDebug("%s, peer conn is restart and set sstatus:%s", pPeer->id, syncStatus[pPeer->sstatus]);
 
   int32_t ret = strcmp(pPeer->fqdn, tsNodeFqdn);
   if (ret > 0 || (ret == 0 && pPeer->port > tsSyncPort)) {
@@ -803,7 +814,7 @@ static void syncProcessSyncRequest(char *msg, SSyncPeer *pPeer) {
   }
 
   if (pPeer->sstatus != TAOS_SYNC_STATUS_INIT) {
-    sDebug("%s, sync is already started", pPeer->id);
+    sDebug("%s, sync is already started for sstatus:%s", pPeer->id, syncStatus[pPeer->sstatus]);
     return;  // already started
   }
 
@@ -821,7 +832,7 @@ static void syncProcessSyncRequest(char *msg, SSyncPeer *pPeer) {
     syncDecPeerRef(pPeer);
   } else {
     pPeer->sstatus = TAOS_SYNC_STATUS_START;
-    sDebug("%s, thread is created to retrieve data", pPeer->id);
+    sDebug("%s, thread is created to retrieve data, set sstatus:%s", pPeer->id, syncStatus[pPeer->sstatus]);
   }
 }
 
@@ -831,9 +842,10 @@ static void syncNotStarted(void *param, void *tmrId) {
 
   pthread_mutex_lock(&pNode->mutex);
   pPeer->timer = NULL;
-  sInfo("%s, sync connection is still not up, restart", pPeer->id);
+  pPeer->sstatus = TAOS_SYNC_STATUS_INIT;
+  sInfo("%s, sync conn is still not up, restart and set sstatus:%s", pPeer->id, syncStatus[pPeer->sstatus]);
   syncRestartConnection(pPeer);
-  pthread_mutex_unlock(&(pNode->mutex));
+  pthread_mutex_unlock(&pNode->mutex);
 }
 
 static void syncTryRecoverFromMaster(void *param, void *tmrId) {
@@ -842,14 +854,14 @@ static void syncTryRecoverFromMaster(void *param, void *tmrId) {
 
   pthread_mutex_lock(&pNode->mutex);
   syncRecoverFromMaster(pPeer);
-  pthread_mutex_unlock(&(pNode->mutex));
+  pthread_mutex_unlock(&pNode->mutex);
 }
 
 static void syncRecoverFromMaster(SSyncPeer *pPeer) {
   SSyncNode *pNode = pPeer->pSyncNode;
 
   if (nodeSStatus != TAOS_SYNC_STATUS_INIT) {
-    sDebug("%s, sync is already started, status:%d", pPeer->id, nodeSStatus);
+    sDebug("%s, sync is already started since sstatus:%s", pPeer->id, syncStatus[nodeSStatus]);
     return;
   }
 
@@ -877,7 +889,7 @@ static void syncRecoverFromMaster(SSyncPeer *pPeer) {
     sError("%s, failed to send sync-req to peer", pPeer->id);
   } else {
     nodeSStatus = TAOS_SYNC_STATUS_START;
-    sInfo("%s, sync-req is sent", pPeer->id);
+    sInfo("%s, sync-req is sent to peer, set sstatus:%s", pPeer->id, syncStatus[nodeSStatus]);
   }
 }
 
@@ -915,7 +927,8 @@ static void syncProcessForwardFromPeer(char *cont, SSyncPeer *pPeer) {
     if (nodeSStatus != TAOS_SYNC_STATUS_INIT) {
       syncSaveIntoBuffer(pPeer, pHead);
     } else {
-      sError("%s, forward discarded, hver:%" PRIu64, pPeer->id, pHead->version);
+      sError("%s, forward discarded since sstatus:%s, hver:%" PRIu64, pPeer->id, syncStatus[nodeSStatus],
+             pHead->version);
     }
   }
 }
@@ -924,8 +937,10 @@ static void syncProcessPeersStatusMsg(char *cont, SSyncPeer *pPeer) {
   SSyncNode *   pNode = pPeer->pSyncNode;
   SPeersStatus *pPeersStatus = (SPeersStatus *)cont;
 
-  sDebug("%s, status msg is received, self:%s sver:%" PRIu64 " peer:%s sver:%" PRIu64 ", ack:%d tranId:%u type:%s", pPeer->id,
-         syncRole[nodeRole], nodeVersion, syncRole[pPeersStatus->role], pPeersStatus->version, pPeersStatus->ack, pPeersStatus->tranId, statusType[pPeersStatus->type]);
+  sDebug("%s, status msg is received, self:%s sstatus:%s sver:%" PRIu64 ", peer:%s sver:%" PRIu64
+         ", ack:%d tranId:%u type:%s pfd:%d",
+         pPeer->id, syncRole[nodeRole], syncStatus[nodeSStatus], nodeVersion, syncRole[pPeersStatus->role],
+         pPeersStatus->version, pPeersStatus->ack, pPeersStatus->tranId, statusType[pPeersStatus->type], pPeer->peerFd);
 
   pPeer->version = pPeersStatus->version;
   syncCheckRole(pPeer, pPeersStatus->peersStatus, pPeersStatus->role);
@@ -982,7 +997,7 @@ static int32_t syncProcessPeerMsg(void *param, void *buffer) {
     }
   }
 
-  pthread_mutex_unlock(&(pNode->mutex));
+  pthread_mutex_unlock(&pNode->mutex);
 
   return code;
 }
@@ -1014,8 +1029,11 @@ static void syncSendPeersStatusMsgToPeer(SSyncPeer *pPeer, char ack, int8_t type
 
   int32_t retLen = taosWriteMsg(pPeer->peerFd, msg, statusMsgLen);
   if (retLen == statusMsgLen) {
-    sDebug("%s, status msg is sent, self:%s sver:%" PRIu64 ", ack:%d tranId:%u type:%s", pPeer->id, syncRole[pPeersStatus->role],
-           pPeersStatus->version, pPeersStatus->ack, pPeersStatus->tranId, statusType[pPeersStatus->type]);
+    sDebug("%s, status msg is sent, self:%s sstatus:%s sver:%" PRIu64 ", peer:%s sstatus:%s sver:%" PRIu64
+           ", ack:%d tranId:%u type:%s pfd:%d",
+           pPeer->id, syncRole[nodeRole], syncStatus[nodeSStatus], nodeVersion, syncRole[pPeer->role],
+           syncStatus[pPeer->sstatus], pPeer->version, pPeersStatus->ack, pPeersStatus->tranId,
+           statusType[pPeersStatus->type], pPeer->peerFd);
   } else {
     sDebug("%s, failed to send status msg, restart", pPeer->id);
     syncRestartConnection(pPeer);
@@ -1048,7 +1066,7 @@ static void syncSetupPeerConnection(SSyncPeer *pPeer) {
   firstPkt.sourceId = pNode->vgId;  // tell arbitrator its vgId
 
   if (taosWriteMsg(connFd, &firstPkt, sizeof(firstPkt)) == sizeof(firstPkt)) {
-    sDebug("%s, connection to peer server is setup", pPeer->id);
+    sDebug("%s, connection to peer server is setup, pfd:%d sfd:%d", pPeer->id, connFd, pPeer->syncFd);
     pPeer->peerFd = connFd;
     pPeer->role = TAOS_SYNC_ROLE_UNSYNCED;
     pPeer->pConn = taosAllocateTcpConn(tsTcpPool, pPeer, connFd);
@@ -1069,7 +1087,7 @@ static void syncCheckPeerConnection(void *param, void *tmrId) {
   sDebug("%s, check peer connection", pPeer->id);
   syncSetupPeerConnection(pPeer);
 
-  pthread_mutex_unlock(&(pNode->mutex));
+  pthread_mutex_unlock(&pNode->mutex);
 }
 
 static void syncCreateRestoreDataThread(SSyncPeer *pPeer) {
@@ -1135,7 +1153,8 @@ static void syncProcessIncommingConnection(int32_t connFd, uint32_t sourceIp) {
       pPeer->syncFd = connFd;
       syncCreateRestoreDataThread(pPeer);
     } else {
-      sDebug("%s, TCP connection is already up, close one", pPeer->id);
+      sDebug("%s, TCP connection is already up(pfd:%d), close one, new pfd:%d sfd:%d", pPeer->id, pPeer->peerFd, connFd,
+             pPeer->syncFd);
       syncClosePeerConn(pPeer);
       pPeer->peerFd = connFd;
       pPeer->pConn = taosAllocateTcpConn(tsTcpPool, pPeer, connFd);
@@ -1145,7 +1164,7 @@ static void syncProcessIncommingConnection(int32_t connFd, uint32_t sourceIp) {
     }
   }
 
-  pthread_mutex_unlock(&(pNode->mutex));
+  pthread_mutex_unlock(&pNode->mutex);
 }
 
 static void syncProcessBrokenLink(void *param) {
@@ -1156,14 +1175,14 @@ static void syncProcessBrokenLink(void *param) {
   if (taosAcquireRef(tsSyncRefId, pNode->rid) == NULL) return;
   pthread_mutex_lock(&pNode->mutex);
 
-  sDebug("%s, TCP link is broken since %s", pPeer->id, strerror(errno));
+  sDebug("%s, TCP link is broken since %s, pfd:%d sfd:%d", pPeer->id, strerror(errno), pPeer->peerFd, pPeer->syncFd);
   pPeer->peerFd = -1;
 
   if (syncDecPeerRef(pPeer) != 0) {
     syncRestartConnection(pPeer);
   }
 
-  pthread_mutex_unlock(&(pNode->mutex));
+  pthread_mutex_unlock(&pNode->mutex);
   taosReleaseRef(tsSyncRefId, pNode->rid);
 }
 
@@ -1239,10 +1258,13 @@ static void syncMonitorNodeRole(void *param, void *tmrId) {
     if (index == pNode->selfIndex) continue;
 
     SSyncPeer *pPeer = pNode->peerInfo[index];
-    if (pPeer->role > TAOS_SYNC_ROLE_UNSYNCED && nodeRole > TAOS_SYNC_ROLE_UNSYNCED) continue;
-    if (pPeer->sstatus > TAOS_SYNC_STATUS_INIT || nodeSStatus > TAOS_SYNC_STATUS_INIT) continue;
+    if (/*pPeer->role > TAOS_SYNC_ROLE_UNSYNCED && */ nodeRole > TAOS_SYNC_ROLE_UNSYNCED) continue;
+    if (/*pPeer->sstatus > TAOS_SYNC_STATUS_INIT || */ nodeSStatus > TAOS_SYNC_STATUS_INIT) continue;
 
+    sDebug("%s, check roles since self:%s sstatus:%s, peer:%s sstatus:%s", pPeer->id, syncRole[pPeer->role],
+           syncStatus[pPeer->sstatus], syncRole[nodeRole], syncStatus[nodeSStatus]);
     syncSendPeersStatusMsgToPeer(pPeer, 1, SYNC_STATUS_CHECK_ROLE, syncGenTranId());
+    break;
   }
 
   pNode->pRoleTimer = taosTmrStart(syncMonitorNodeRole, SYNC_ROLE_TIMER, (void *)pNode->rid, tsSyncTmrCtrl);
@@ -1271,7 +1293,7 @@ static void syncMonitorFwdInfos(void *param, void *tmrId) {
       }
 
       syncRemoveConfirmedFwdInfo(pNode);
-      pthread_mutex_unlock(&(pNode->mutex));
+      pthread_mutex_unlock(&pNode->mutex);
     }
 
     pNode->pFwdTimer = taosTmrStart(syncMonitorFwdInfos, SYNC_FWD_TIMER, (void *)pNode->rid, tsSyncTmrCtrl);
@@ -1339,7 +1361,7 @@ static int32_t syncForwardToPeerImpl(SSyncNode *pNode, void *data, void *mhandle
     }
   }
 
-  pthread_mutex_unlock(&(pNode->mutex));
+  pthread_mutex_unlock(&pNode->mutex);
 
   return code;
 }
diff --git a/src/sync/src/syncRestore.c b/src/sync/src/syncRestore.c
index b31ec5f7c74b03258ef1a638c890b9886dee8def..466c39060ab9b3639540d56dccc439880db21093 100644
--- a/src/sync/src/syncRestore.c
+++ b/src/sync/src/syncRestore.c
@@ -267,7 +267,7 @@ static int32_t syncRestoreDataStepByStep(SSyncPeer *pPeer) {
   nodeSStatus = TAOS_SYNC_STATUS_FILE;
   uint64_t fversion = 0;
 
-  sDebug("%s, start to restore file", pPeer->id);
+  sDebug("%s, start to restore file, set sstatus:%s", pPeer->id, syncStatus[nodeSStatus]);
   int32_t code = syncRestoreFile(pPeer, &fversion);
   if (code < 0) {
     sError("%s, failed to restore file", pPeer->id);
@@ -291,7 +291,7 @@ static int32_t syncRestoreDataStepByStep(SSyncPeer *pPeer) {
   }
 
   nodeSStatus = TAOS_SYNC_STATUS_CACHE;
-  sDebug("%s, start to insert buffered points", pPeer->id);
+  sDebug("%s, start to insert buffered points, set sstatus:%s", pPeer->id, syncStatus[nodeSStatus]);
   if (syncProcessBufferedFwd(pPeer) < 0) {
     sError("%s, failed to insert buffered points", pPeer->id);
     return -1;
@@ -327,6 +327,8 @@ void *syncRestoreData(void *param) {
   (*pNode->notifyRole)(pNode->vgId, nodeRole);
 
   nodeSStatus = TAOS_SYNC_STATUS_INIT;
+  sInfo("%s, sync over, set sstatus:%s", pPeer->id, syncStatus[nodeSStatus]);
+
   taosClose(pPeer->syncFd);
   syncCloseRecvBuffer(pNode);
   __sync_fetch_and_sub(&tsSyncNum, 1);
diff --git a/src/sync/src/syncRetrieve.c b/src/sync/src/syncRetrieve.c
index b6dacaa262f1e58b8406650003c5775efbaebf3f..04d4ce32cb5c4b42aac7a89311c575abda07bc02 100644
--- a/src/sync/src/syncRetrieve.c
+++ b/src/sync/src/syncRetrieve.c
@@ -318,6 +318,7 @@ static int32_t syncProcessLastWal(SSyncPeer *pPeer, char *wname, int64_t index)
       if (((event & IN_MODIFY) == 0) || once) {
         if (fversion == 0) {
           pPeer->sstatus = TAOS_SYNC_STATUS_CACHE;  // start to forward pkt
+          sDebug("%s, fversion is 0 then set sstatus:%s", pPeer->id, syncStatus[pPeer->sstatus]);
           fversion = nodeVersion;                   // must read data to fversion
         }
       }
@@ -416,8 +417,9 @@ static int32_t syncRetrieveWal(SSyncPeer *pPeer) {
   }
 
   if (code == 0) {
-    sInfo("%s, wal retrieve is finished", pPeer->id);
     pPeer->sstatus = TAOS_SYNC_STATUS_CACHE;
+    sInfo("%s, wal retrieve is finished, set sstatus:%s", pPeer->id, syncStatus[pPeer->sstatus]);
+
     SWalHead walHead;
     memset(&walHead, 0, sizeof(walHead));
     code = taosWriteMsg(pPeer->syncFd, &walHead, sizeof(walHead));
@@ -445,7 +447,7 @@ static int32_t syncRetrieveDataStepByStep(SSyncPeer *pPeer) {
 
   pPeer->sversion = 0;
   pPeer->sstatus = TAOS_SYNC_STATUS_FILE;
-  sInfo("%s, start to retrieve file", pPeer->id);
+  sInfo("%s, start to retrieve file, set sstatus:%s", pPeer->id, syncStatus[pPeer->sstatus]);
   if (syncRetrieveFile(pPeer) < 0) {
     sError("%s, failed to retrieve file", pPeer->id);
     return -1;
diff --git a/src/util/src/tsocket.c b/src/util/src/tsocket.c
index 1be79b7bbd32a20c5f784ad10ca5aeff877eaac5..2543c8170896825ae2a94349c0218e7d99ce8592 100644
--- a/src/util/src/tsocket.c
+++ b/src/util/src/tsocket.c
@@ -107,7 +107,7 @@ int32_t taosWriteMsg(SOCKET fd, void *buf, int32_t nbytes) {
   while (nleft > 0) {
     nwritten = (int32_t)taosWriteSocket(fd, (char *)ptr, (size_t)nleft);
     if (nwritten <= 0) {
-      if (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK)
+      if (errno == EINTR /* || errno == EAGAIN || errno == EWOULDBLOCK */)
         continue;
       else
         return -1;
@@ -133,7 +133,7 @@ int32_t taosReadMsg(SOCKET fd, void *buf, int32_t nbytes) {
     if (nread == 0) {
       break;
     } else if (nread < 0) {
-      if (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK) {
+      if (errno == EINTR/* || errno == EAGAIN || errno == EWOULDBLOCK*/) {
         continue;
       } else {
         return -1;