diff --git a/src/os/src/detail/osTimer.c b/src/os/src/detail/osTimer.c
index 9883a03a0933075616b69800fe6e34a36fc6c746..1d3ba30def9416785d72556ac218bd5a48aead77 100644
--- a/src/os/src/detail/osTimer.c
+++ b/src/os/src/detail/osTimer.c
@@ -89,12 +89,17 @@ int taosInitTimer(void (*callback)(int), int ms) {
   if (code != 0) {
     uError("failed to create timer thread");
     return -1;
+  } else {
+    uDebug("timer thread:0x%08" PRIx64 " is created", taosGetPthreadId(timerThread));
   }
+
   return 0;
 }
 
 void taosUninitTimer() {
   stopTimer = true;
+
+  uDebug("join timer thread:0x%08" PRIx64, taosGetPthreadId(timerThread));
   pthread_join(timerThread, NULL);
 }
 
diff --git a/src/query/src/qExecutor.c b/src/query/src/qExecutor.c
index c257e8468f98839f4ac70d5227558ba9b01af0c6..05487d435d933d019fda5fbe1551a5a2118fad22 100644
--- a/src/query/src/qExecutor.c
+++ b/src/query/src/qExecutor.c
@@ -1667,7 +1667,7 @@ static void rowwiseApplyFunctions(SQueryRuntimeEnv *pRuntimeEnv, SDataStatis *pS
 
   _end:
   assert(offset >= 0 && tsCols != NULL);
-  if (prevTs != INT64_MIN) {
+  if (prevTs != INT64_MIN && prevTs != *(int64_t*)pRuntimeEnv->prevRow[0]) {
     assert(prevRowIndex >= 0);
     item->lastKey = prevTs + step;
   }
@@ -7728,4 +7728,4 @@ void** qReleaseQInfo(void* pMgmt, void* pQInfo, bool freeHandle) {
 
   taosCacheRelease(pQueryMgmt->qinfoPool, pQInfo, freeHandle);
   return 0;
-}
\ No newline at end of file
+}
diff --git a/src/sync/src/syncRestore.c b/src/sync/src/syncRestore.c
index 606760c928cdaea3c3fae3b80573b29404bfafbd..78520c660875ccd25d42857b89359fbd15f33b35 100644
--- a/src/sync/src/syncRestore.c
+++ b/src/sync/src/syncRestore.c
@@ -90,7 +90,7 @@ static int32_t syncRestoreFile(SSyncPeer *pPeer, uint64_t *fversion) {
       break;
     }
 
-    sDebug("%s, file:%s info is received from master, index:%d size:%" PRId64 " fver:%" PRIu64 " magic:%d", pPeer->id,
+    sDebug("%s, file:%s info is received from master, index:%d size:%" PRId64 " fver:%" PRIu64 " magic:%u", pPeer->id,
            minfo.name, minfo.index, minfo.size, minfo.fversion, minfo.magic);
 
     // remove extra files on slave between the current and last index
@@ -100,13 +100,13 @@ static int32_t syncRestoreFile(SSyncPeer *pPeer, uint64_t *fversion) {
     // check the file info
     sinfo = minfo;
     sinfo.magic = (*pNode->getFileInfo)(pNode->vgId, sinfo.name, &sinfo.index, TAOS_SYNC_MAX_INDEX, &sinfo.size, &sinfo.fversion);
-    sDebug("%s, local file:%s info, index:%d size:%" PRId64 " fver:%" PRIu64 " magic:%d", pPeer->id, sinfo.name,
+    sDebug("%s, local file:%s info, index:%d size:%" PRId64 " fver:%" PRIu64 " magic:%u", pPeer->id, sinfo.name,
            sinfo.index, sinfo.size, sinfo.fversion, sinfo.magic);
 
     // if file not there or magic is not the same, file shall be synced
     memset(&fileAck, 0, sizeof(SFileAck));
     syncBuildFileAck(&fileAck, pNode->vgId);
-    fileAck.sync = (sinfo.magic != minfo.magic || sinfo.name[0] == 0) ? 1 : 0;
+    fileAck.sync = (sinfo.magic != minfo.magic || sinfo.size != minfo.size || sinfo.name[0] == 0) ? 1 : 0;
 
     // send file ack
     ret = taosWriteMsg(pPeer->syncFd, &fileAck, sizeof(SFileAck));
diff --git a/src/sync/src/syncRetrieve.c b/src/sync/src/syncRetrieve.c
index d755ee9aa6f06d27eac144da67295ba02f98610a..153886102e807b9fe161585705691ff92b4186a0 100644
--- a/src/sync/src/syncRetrieve.c
+++ b/src/sync/src/syncRetrieve.c
@@ -104,7 +104,7 @@ static int32_t syncRetrieveFile(SSyncPeer *pPeer) {
     fileInfo.magic = (*pNode->getFileInfo)(pNode->vgId, fileInfo.name, &fileInfo.index, TAOS_SYNC_MAX_INDEX,
                                            &fileInfo.size, &fileInfo.fversion);
     syncBuildFileInfo(&fileInfo, pNode->vgId);
-    sDebug("%s, file:%s info is sent, index:%d size:%" PRId64 " fver:%" PRIu64 " magic:%d", pPeer->id, fileInfo.name,
+    sDebug("%s, file:%s info is sent, index:%d size:%" PRId64 " fver:%" PRIu64 " magic:%u", pPeer->id, fileInfo.name,
            fileInfo.index, fileInfo.size, fileInfo.fversion, fileInfo.magic);
 
     // send the file info
@@ -143,10 +143,10 @@ static int32_t syncRetrieveFile(SSyncPeer *pPeer) {
     // if sync is not required, continue
     if (fileAck.sync == 0) {
       fileInfo.index++;
-      sDebug("%s, %s is the same", pPeer->id, fileInfo.name);
+      sDebug("%s, %s is the same, fver:%" PRIu64, pPeer->id, fileInfo.name, fileInfo.fversion);
       continue;
     } else {
-      sDebug("%s, %s will be sent", pPeer->id, fileInfo.name);
+      sDebug("%s, %s will be sent, fver:%" PRIu64, pPeer->id, fileInfo.name, fileInfo.fversion);
     }
 
     // get the full path to file
@@ -328,7 +328,8 @@ static int32_t syncProcessLastWal(SSyncPeer *pPeer, char *wname, int64_t index)
     // if bytes > 0, file is updated, or fversion is not reached but file still open, read again
     once = 1;
     offset += bytes;
-    sDebug("%s, continue retrieve last wal, bytes:%d offset:%" PRId64, pPeer->id, bytes, offset);
+    sDebug("%s, continue retrieve last wal, bytes:%d offset:%" PRId64 " sver:%" PRIu64 " fver:%" PRIu64, pPeer->id,
+           bytes, offset, pPeer->sversion, fversion);
   }
 
   return -1;
diff --git a/src/vnode/src/vnodeWrite.c b/src/vnode/src/vnodeWrite.c
index 2dc814b8f39058cb25a9bed2decc838fbf848e88..5c2e871eb646a006484bcdc34995bda70a3ede8d 100644
--- a/src/vnode/src/vnodeWrite.c
+++ b/src/vnode/src/vnodeWrite.c
@@ -90,7 +90,10 @@ int32_t vnodeProcessWrite(void *vparam, void *wparam, int32_t qtype, void *rpara
 
   // write into WAL
   code = walWrite(pVnode->wal, pHead);
-  if (code < 0) return code;
+  if (code < 0) {
+    vError("vgId:%d, hver:%" PRIu64 " vver:%" PRIu64 " code:0x%x", pVnode->vgId, pHead->version, pVnode->version, code);
+    return code;
+  }
 
   pVnode->version = pHead->version;
 
diff --git a/tests/tsim/src/simExe.c b/tests/tsim/src/simExe.c
index 2db750cdd302c63522e008e3ea324230dd87b6e5..0323f6ca687c40c8bc70b0672abe4e2f7852a8cc 100644
--- a/tests/tsim/src/simExe.c
+++ b/tests/tsim/src/simExe.c
@@ -292,6 +292,9 @@ bool simExecuteRunBackCmd(SScript *script, char *option) {
   if (pthread_create(&newScript->bgPid, NULL, simExecuteScript, (void *)newScript) != 0) {
     sprintf(script->error, "lineNum:%d. create background thread failed", script->lines[script->linePos].lineNum);
     return false;
+  } else {
+    simDebug("script:%s, background thread:0x%08" PRIx64 " is created", newScript->fileName,
+             taosGetPthreadId(newScript->bgPid));
   }
 
   script->linePos++;
@@ -448,7 +451,6 @@ void simCloseNativeConnect(SScript *script) {
 
   simDebug("script:%s, taos:%p closed", script->fileName, script->taos);
   taos_close(script->taos);
-  taosMsleep(1200);
 
   script->taos = NULL;
 }
diff --git a/tests/tsim/src/simMain.c b/tests/tsim/src/simMain.c
index 33fd24dd5823b8ec7bf818cec7c36ddac783bc24..8f13254f68165a9e26ecac2406538f8cba905120 100644
--- a/tests/tsim/src/simMain.c
+++ b/tests/tsim/src/simMain.c
@@ -40,14 +40,14 @@ int32_t main(int32_t argc, char *argv[]) {
       printf("usage: %s [options] \n", argv[0]);
       printf("       [-c config]: config directory, default is: %s\n", configDir);
       printf("       [-f script]: script filename\n");
-      exit(0);
+      return 0;
     }
   }
 
   if (!simSystemInit()) {
     simError("failed to initialize the system");
     simSystemCleanUp();
-    exit(1);
+    return -1;
   }
 
   simInfo("simulator is running ...");
@@ -56,7 +56,7 @@ int32_t main(int32_t argc, char *argv[]) {
   SScript *script = simParseScript(scriptFile);
   if (script == NULL) {
     simError("parse script file:%s failed", scriptFile);
-    exit(-1);
+    return -1;
   }
 
   simScriptList[++simScriptPos] = script;
diff --git a/tests/tsim/src/simSystem.c b/tests/tsim/src/simSystem.c
index 693ade7b35a095b499198db9dcc27335f73e14bd..bf47c56718b7377aa5cd4fd48269eec0fc9e0b38 100644
--- a/tests/tsim/src/simSystem.c
+++ b/tests/tsim/src/simSystem.c
@@ -93,27 +93,34 @@ void simFreeScript(SScript *script) {
 
     for (int32_t i = 0; i < script->bgScriptLen; ++i) {
       SScript *bgScript = script->bgScripts[i];
-      simInfo("script:%s, set stop flag", script->fileName);
+      simDebug("script:%s, is background script, set stop flag", bgScript->fileName);
       bgScript->killed = true;
       if (taosCheckPthreadValid(bgScript->bgPid)) {
         pthread_join(bgScript->bgPid, NULL);
       }
+
+      simDebug("script:%s, background thread joined", bgScript->fileName);
+      taos_close(bgScript->taos);
+      tfree(bgScript->lines);
+      tfree(bgScript->optionBuffer);
+      tfree(bgScript);
     }
-  }
 
-  simDebug("script:%s, is freed", script->fileName);
-  taos_close(script->taos);
-  tfree(script->lines);
-  tfree(script->optionBuffer);
-  tfree(script);
+    simDebug("script:%s, is cleaned", script->fileName);
+    taos_close(script->taos);
+    tfree(script->lines);
+    tfree(script->optionBuffer);
+    tfree(script);
+  }
 }
 
 SScript *simProcessCallOver(SScript *script) {
   if (script->type == SIM_SCRIPT_TYPE_MAIN) {
+    simDebug("script:%s, is main script, set stop flag", script->fileName);
     if (script->killed) {
       simInfo("script:" FAILED_PREFIX "%s" FAILED_POSTFIX ", " FAILED_PREFIX "failed" FAILED_POSTFIX ", error:%s",
               script->fileName, script->error);
-      exit(-1);
+      return NULL;
     } else {
       simInfo("script:" SUCCESS_PREFIX "%s" SUCCESS_POSTFIX ", " SUCCESS_PREFIX "success" SUCCESS_POSTFIX,
               script->fileName);
@@ -125,13 +132,13 @@ SScript *simProcessCallOver(SScript *script) {
       if (simScriptPos == -1) {
         simInfo("----------------------------------------------------------------------");
         simInfo("Simulation Test Done, " SUCCESS_PREFIX "%d" SUCCESS_POSTFIX " Passed:\n", simScriptSucced);
-        exit(0);
+        return NULL;
       }
 
       return simScriptList[simScriptPos];
     }
   } else {
-    simInfo("script:%s, is stopped by main script", script->fileName);
+    simDebug("script:%s,  is stopped", script->fileName);
     simFreeScript(script);
     return NULL;
   }
@@ -161,5 +168,6 @@ void *simExecuteScript(void *inputScript) {
     }
   }
 
+  simInfo("thread is stopped");
   return NULL;
 }