diff --git a/src/tsdb/inc/tsdbMain.h b/src/tsdb/inc/tsdbMain.h
index 6a54cb23998ff48ffeb2acb552e6ce5f7a6cbeac..d6f73ee1be8e8ae812c6b47279c17b31642e2871 100644
--- a/src/tsdb/inc/tsdbMain.h
+++ b/src/tsdb/inc/tsdbMain.h
@@ -183,10 +183,10 @@ typedef struct {
 } STsdbFileH;
 
 typedef struct {
-  int         numOfFGroups;
-  SFileGroup *base;
-  SFileGroup *pFileGroup;
   int         direction;
+  STsdbFileH* pFileH;
+  int         fileId;
+  int         index;
 } SFileGroupIter;
 
 // ------------------ tsdbMain.c
diff --git a/src/tsdb/src/tsdbFile.c b/src/tsdb/src/tsdbFile.c
index 6e7b39830eaea94b322cc44963f8569a453f019c..7d8a68182b1d2d29d6c23a96e69037efdf334932 100644
--- a/src/tsdb/src/tsdbFile.c
+++ b/src/tsdb/src/tsdbFile.c
@@ -156,8 +156,10 @@ SFileGroup *tsdbCreateFGroupIfNeed(STsdbRepo *pRepo, char *dataDir, int fid) {
         goto _err;
     }
 
+    pthread_rwlock_wrlock(&pFileH->fhlock);
     pFileH->pFGroup[pFileH->nFGroups++] = fGroup;
     qsort((void *)(pFileH->pFGroup), pFileH->nFGroups, sizeof(SFileGroup), compFGroup);
+    pthread_rwlock_unlock(&pFileH->fhlock);
     return tsdbSearchFGroup(pFileH, fid, TD_EQ);
   }
 
@@ -168,54 +170,72 @@ _err:
   return NULL;
 }
 
-void tsdbInitFileGroupIter(STsdbFileH *pFileH, SFileGroupIter *pIter, int direction) { // TODO
+void tsdbInitFileGroupIter(STsdbFileH *pFileH, SFileGroupIter *pIter, int direction) {
+  pIter->pFileH = pFileH;
   pIter->direction = direction;
-  pIter->base = pFileH->pFGroup;
-  pIter->numOfFGroups = pFileH->nFGroups;
+
   if (pFileH->nFGroups == 0) {
-    pIter->pFileGroup = NULL;
+    pIter->index = -1;
+    pIter->fileId = -1;
   } else {
     if (direction == TSDB_FGROUP_ITER_FORWARD) {
-      pIter->pFileGroup = pFileH->pFGroup;
+      pIter->index = 0;
     } else {
-      pIter->pFileGroup = pFileH->pFGroup + pFileH->nFGroups - 1;
+      pIter->index = pFileH->nFGroups - 1;
     }
+    pIter->fileId = pFileH->pFGroup[pIter->index].fileId;
   }
 }
 
-void tsdbSeekFileGroupIter(SFileGroupIter *pIter, int fid) { // TODO
-  if (pIter->numOfFGroups == 0) {
-    assert(pIter->pFileGroup == NULL);
+void tsdbSeekFileGroupIter(SFileGroupIter *pIter, int fid) {
+  STsdbFileH *pFileH = pIter->pFileH;
+
+  if (pFileH->nFGroups == 0) {
+    pIter->index = -1;
+    pIter->fileId = -1;
     return;
   }
 
   int   flags = (pIter->direction == TSDB_FGROUP_ITER_FORWARD) ? TD_GE : TD_LE;
-  void *ptr = taosbsearch(&fid, pIter->base, pIter->numOfFGroups, sizeof(SFileGroup), keyFGroupCompFunc, flags);
+  void *ptr = taosbsearch(&fid, (void *)pFileH->pFGroup, pFileH->nFGroups, sizeof(SFileGroup), keyFGroupCompFunc, flags);
   if (ptr == NULL) {
-    pIter->pFileGroup = NULL;
+    pIter->index = -1;
+    pIter->fileId = -1;
   } else {
-    pIter->pFileGroup = (SFileGroup *)ptr;
+    pIter->index = POINTER_DISTANCE(ptr, pFileH->pFGroup) / sizeof(SFileGroup);
+    pIter->fileId = ((SFileGroup *)ptr)->fileId;
   }
 }
 
-SFileGroup *tsdbGetFileGroupNext(SFileGroupIter *pIter) {//TODO
-  SFileGroup *ret = pIter->pFileGroup;
-  if (ret == NULL) return NULL;
+SFileGroup *tsdbGetFileGroupNext(SFileGroupIter *pIter) {
+  STsdbFileH *pFileH = pIter->pFileH;
+  SFileGroup *pFGroup = NULL;
+
+  if (pIter->index < 0 || pIter->index >= pFileH->nFGroups || pIter->fileId < 0) return NULL;
+
+  pFGroup = &pFileH->pFGroup[pIter->index];
+  if (pFGroup->fileId != pIter->fileId) {
+    tsdbSeekFileGroupIter(pIter, pIter->fileId);
+  }
+
+  if (pIter->index < 0) return NULL;
+
+  pFGroup = &pFileH->pFGroup[pIter->index];
+  ASSERT(pFGroup->fileId == pIter->fileId);
 
   if (pIter->direction == TSDB_FGROUP_ITER_FORWARD) {
-    if ((pIter->pFileGroup + 1) == (pIter->base + pIter->numOfFGroups)) {
-      pIter->pFileGroup = NULL;
-    } else {
-      pIter->pFileGroup += 1;
-    }
+    pIter->index++;
   } else {
-    if (pIter->pFileGroup == pIter->base) {
-      pIter->pFileGroup = NULL;
-    } else {
-      pIter->pFileGroup -= 1;
-    }
+    pIter->index--;
   }
-  return ret;
+
+  if (pIter->index >= 0 && pIter->index < pFileH->nFGroups) {
+    pIter->fileId = pFileH->pFGroup[pIter->index].fileId;
+  } else {
+    pIter->fileId = -1;
+  }
+
+  return pFGroup;
 }
 
 int tsdbOpenFile(SFile *pFile, int oflag) {
diff --git a/src/tsdb/src/tsdbMain.c b/src/tsdb/src/tsdbMain.c
index b04b0be9bad1b7cac44227a0ade32ed77175f0ea..2b6dc66e2db779083047bdb0c2089096b249c6d6 100644
--- a/src/tsdb/src/tsdbMain.c
+++ b/src/tsdb/src/tsdbMain.c
@@ -787,6 +787,7 @@ static int tsdbRestoreInfo(STsdbRepo *pRepo) {
   tsdbInitFileGroupIter(pFileH, &iter, TSDB_ORDER_DESC);
   while ((pFGroup = tsdbGetFileGroupNext(&iter)) != NULL) {
     if (tsdbSetAndOpenHelperFile(&rhelper, pFGroup) < 0) goto _err;
+    if (tsdbLoadCompIdx(&rhelper, NULL) < 0) goto _err;
     for (int i = 1; i < pMeta->maxTables; i++) {
       STable *pTable = pMeta->tables[i];
       if (pTable == NULL) continue;
diff --git a/src/tsdb/src/tsdbMemTable.c b/src/tsdb/src/tsdbMemTable.c
index 506f3c11c104bed4a84641f7d95538a62bdbfec7..d5e90bcd601774e5b1bfa0b89fabf7ca585abd8e 100644
--- a/src/tsdb/src/tsdbMemTable.c
+++ b/src/tsdb/src/tsdbMemTable.c
@@ -603,6 +603,11 @@ static int tsdbCommitToFile(STsdbRepo *pRepo, int fid, SCommitIter *iters, SRWHe
     goto _err;
   }
 
+  if (tsdbLoadCompIdx(pHelper, NULL) < 0) {
+    tsdbError("vgId:%d failed to load SCompIdx part since %s", REPO_ID(pRepo), tstrerror(terrno));
+    goto _err;
+  }
+
   // Loop to commit data in each table
   for (int tid = 1; tid < pMem->maxTables; tid++) {
     SCommitIter *pIter = iters + tid;
@@ -651,12 +656,20 @@ static int tsdbCommitToFile(STsdbRepo *pRepo, int fid, SCommitIter *iters, SRWHe
   tsdbCloseHelperFile(pHelper, 0);
 
   pthread_rwlock_wrlock(&(pFileH->fhlock));
+
 #ifdef TSDB_IDX
-  pGroup->files[TSDB_FILE_TYPE_IDX] = *(helperIdxF(pHelper));
+  rename(helperNewIdxF(pHelper)->fname, helperIdxF(pHelper)->fname);
+  pGroup->files[TSDB_FILE_TYPE_IDX].info = helperNewIdxF(pHelper)->info;
 #endif
-  pGroup->files[TSDB_FILE_TYPE_HEAD] = *(helperHeadF(pHelper));
-  pGroup->files[TSDB_FILE_TYPE_DATA] = *(helperDataF(pHelper));
-  pGroup->files[TSDB_FILE_TYPE_LAST] = *(helperLastF(pHelper));
+
+  rename(helperNewHeadF(pHelper)->fname, helperHeadF(pHelper)->fname);
+  pGroup->files[TSDB_FILE_TYPE_HEAD].info = helperNewHeadF(pHelper)->info;
+
+  rename(helperNewLastF(pHelper)->fname, helperLastF(pHelper)->fname);
+  pGroup->files[TSDB_FILE_TYPE_LAST].info = helperNewLastF(pHelper)->info;
+
+  pGroup->files[TSDB_FILE_TYPE_DATA].info = helperDataF(pHelper)->info;
+
   pthread_rwlock_unlock(&(pFileH->fhlock));
 
   return 0;
diff --git a/src/tsdb/src/tsdbRWHelper.c b/src/tsdb/src/tsdbRWHelper.c
index 8d3908666ed0cd9a517fabec3b7e7ea20a0885c7..b04d08f850a7d8cc49cea8586cfa60c9458e4561 100644
--- a/src/tsdb/src/tsdbRWHelper.c
+++ b/src/tsdb/src/tsdbRWHelper.c
@@ -118,12 +118,12 @@ int tsdbSetAndOpenHelperFile(SRWHelper *pHelper, SFileGroup *pGroup) {
 
   // Open the files
 #ifdef TSDB_IDX
-  if (tsdbOpenFile(helperIdxF(pHelper), O_RDONLY) < 0) goto _err;
+  if (tsdbOpenFile(helperIdxF(pHelper), O_RDONLY) < 0) return -1;
 #endif
-  if (tsdbOpenFile(helperHeadF(pHelper), O_RDONLY) < 0) goto _err;
+  if (tsdbOpenFile(helperHeadF(pHelper), O_RDONLY) < 0) return -1;
   if (helperType(pHelper) == TSDB_WRITE_HELPER) {
-    if (tsdbOpenFile(helperDataF(pHelper), O_RDWR) < 0) goto _err;
-    if (tsdbOpenFile(helperLastF(pHelper), O_RDWR) < 0) goto _err;
+    if (tsdbOpenFile(helperDataF(pHelper), O_RDWR) < 0) return -1;
+    if (tsdbOpenFile(helperLastF(pHelper), O_RDWR) < 0) return -1;
 
 #ifdef TSDB_IDX
     // Create and open .i file
@@ -144,23 +144,20 @@ int tsdbSetAndOpenHelperFile(SRWHelper *pHelper, SFileGroup *pGroup) {
     // Create and open .l file if should
     if (tsdbShouldCreateNewLast(pHelper)) {
       pFile = helperNewLastF(pHelper);
-      if (tsdbOpenFile(pFile, O_WRONLY | O_CREAT) < 0) goto _err;
+      if (tsdbOpenFile(pFile, O_WRONLY | O_CREAT) < 0) return -1;
       pFile->info.size = TSDB_FILE_HEAD_SIZE;
       pFile->info.magic = TSDB_FILE_INIT_MAGIC;
       pFile->info.len = 0;
       if (tsdbUpdateFileHeader(pFile, 0) < 0) return -1;
     }
   } else {
-    if (tsdbOpenFile(helperDataF(pHelper), O_RDONLY) < 0) goto _err;
-    if (tsdbOpenFile(helperLastF(pHelper), O_RDONLY) < 0) goto _err;
+    if (tsdbOpenFile(helperDataF(pHelper), O_RDONLY) < 0) return -1;
+    if (tsdbOpenFile(helperLastF(pHelper), O_RDONLY) < 0) return -1;
   }
 
   helperSetState(pHelper, TSDB_HELPER_FILE_SET_AND_OPEN);
 
-  return tsdbLoadCompIdx(pHelper, NULL);
-
-_err:
-  return -1;
+  return 0;
 }
 
 int tsdbCloseHelperFile(SRWHelper *pHelper, bool hasError) {
@@ -183,8 +180,12 @@ int tsdbCloseHelperFile(SRWHelper *pHelper, bool hasError) {
   pFile = helperDataF(pHelper);
   if (pFile->fd > 0) {
     if (helperType(pHelper) == TSDB_WRITE_HELPER) {
-      tsdbUpdateFileHeader(pFile, 0);
-      fsync(pFile->fd);
+      if (!hasError) {
+        tsdbUpdateFileHeader(pFile, 0);
+        fsync(pFile->fd);
+      } else {
+        // TODO: shrink back to origin
+      }
     }
     close(pFile->fd);
     pFile->fd = -1;
@@ -193,7 +194,12 @@ int tsdbCloseHelperFile(SRWHelper *pHelper, bool hasError) {
   pFile = helperLastF(pHelper);
   if (pFile->fd > 0) {
     if (helperType(pHelper) == TSDB_WRITE_HELPER && !TSDB_NLAST_FILE_OPENED(pHelper)) {
-      fsync(pFile->fd);
+      if (!hasError) {
+        tsdbUpdateFileHeader(pFile, 0);
+        fsync(pFile->fd);
+      } else {
+        // TODO: shrink back to origin
+      }
     }
     close(pFile->fd);
     pFile->fd = -1;
@@ -203,60 +209,36 @@ int tsdbCloseHelperFile(SRWHelper *pHelper, bool hasError) {
 #ifdef TSDB_IDX
     pFile = helperNewIdxF(pHelper);
     if (pFile->fd > 0) {
-      if (!hasError) tsdbUpdateFileHeader(pFile, 0);
-      fsync(pFile->fd);
+      if (!hasError) {
+        tsdbUpdateFileHeader(pFile, 0);
+        fsync(pFile->fd);
+      }
       close(pFile->fd);
       pFile->fd = -1;
-      if (hasError) {
-        (void)remove(pFile->fname);
-      } else {
-        if (rename(pFile->fname, helperIdxF(pHelper)->fname) < 0) {
-          tsdbError("failed to rename file from %s to %s since %s", pFile->fname, helperIdxF(pHelper)->fname,
-                    strerror(errno));
-          terrno = TAOS_SYSTEM_ERROR(errno);
-          return -1;
-        }
-        helperIdxF(pHelper)->info = pFile->info;
-      }
+      if (hasError) (void)remove(pFile->fname);
     }
 #endif
 
     pFile = helperNewHeadF(pHelper);
     if (pFile->fd > 0) {
-      if (!hasError) tsdbUpdateFileHeader(pFile, 0);
-      fsync(pFile->fd);
+      if (!hasError) {
+        tsdbUpdateFileHeader(pFile, 0);
+        fsync(pFile->fd);
+      }
       close(pFile->fd);
       pFile->fd = -1;
-      if (hasError) {
-        (void)remove(pFile->fname);
-      } else {
-        if (rename(pFile->fname, helperHeadF(pHelper)->fname) < 0) {
-          tsdbError("failed to rename file from %s to %s since %s", pFile->fname, helperHeadF(pHelper)->fname,
-                    strerror(errno));
-          terrno = TAOS_SYSTEM_ERROR(errno);
-          return -1;
-        }
-        helperHeadF(pHelper)->info = pFile->info;
-      }
+      if (hasError) (void)remove(pFile->fname);
     }
 
     pFile = helperNewLastF(pHelper);
     if (pFile->fd > 0) {
-      if (!hasError) tsdbUpdateFileHeader(pFile, 0);
-      fsync(pFile->fd);
+      if (!hasError) {
+        tsdbUpdateFileHeader(pFile, 0);
+        fsync(pFile->fd);
+      }
       close(pFile->fd);
       pFile->fd = -1;
-      if (hasError) {
-        (void)remove(pFile->fname);
-      } else {
-        if (rename(pFile->fname, helperLastF(pHelper)->fname) < 0) {
-          tsdbError("failed to rename file from %s to %s since %s", pFile->fname, helperLastF(pHelper)->fname,
-                    strerror(errno));
-          terrno = TAOS_SYSTEM_ERROR(errno);
-          return -1;
-        }
-        helperLastF(pHelper)->info = helperNewLastF(pHelper)->info;
-      }
+      if (hasError) (void)remove(pFile->fname);
     }
   }
   return 0;
diff --git a/src/tsdb/src/tsdbRead.c b/src/tsdb/src/tsdbRead.c
index 0e3a657fde547f186623734e9dcf24b9087e9f27..8515fb52e3015fa8e8ee6c27b0f34f3361f0b99b 100644
--- a/src/tsdb/src/tsdbRead.c
+++ b/src/tsdb/src/tsdbRead.c
@@ -555,16 +555,6 @@ static int32_t binarySearchForBlock(SCompBlock* pBlock, int32_t numOfBlocks, TSK
 }
 
 static int32_t getFileCompInfo(STsdbQueryHandle* pQueryHandle, int32_t* numOfBlocks) {
-  SFileGroup* fileGroup = pQueryHandle->pFileGroup;
-  assert(fileGroup->files[TSDB_FILE_TYPE_HEAD].fname > 0);
-
-  int32_t code = tsdbSetAndOpenHelperFile(&pQueryHandle->rhelper, fileGroup);
-
-  //open file failed, return error code to client
-  if (code != TSDB_CODE_SUCCESS) {
-    return code;
-  }
-
   // load all the comp offset value for all tables in this file
   *numOfBlocks = 0;
   size_t numOfTables = taosArrayGetSize(pQueryHandle->pTableCheckInfo);
@@ -1461,12 +1451,20 @@ static int32_t getDataBlocksInFilesImpl(STsdbQueryHandle* pQueryHandle, bool* ex
   STsdbCfg* pCfg = &pQueryHandle->pTsdb->config;
   STimeWindow win = TSWINDOW_INITIALIZER;
 
-  while ((pQueryHandle->pFileGroup = tsdbGetFileGroupNext(&pQueryHandle->fileIter)) != NULL) {
+  while (true) {
+    pthread_rwlock_rdlock(&pQueryHandle->pTsdb->tsdbFileH->fhlock);
+
+    if ((pQueryHandle->pFileGroup = tsdbGetFileGroupNext(&pQueryHandle->fileIter)) == NULL) {
+      pthread_rwlock_unlock(&pQueryHandle->pTsdb->tsdbFileH->fhlock);
+      break;
+    }
+
     tsdbGetFidKeyRange(pCfg->daysPerFile, pCfg->precision, pQueryHandle->pFileGroup->fileId, &win.skey, &win.ekey);
 
     // current file are not overlapped with query time window, ignore remain files
     if ((ASCENDING_TRAVERSE(pQueryHandle->order) && win.skey > pQueryHandle->window.ekey) ||
         (!ASCENDING_TRAVERSE(pQueryHandle->order) && win.ekey < pQueryHandle->window.ekey)) {
+      pthread_rwlock_unlock(&pQueryHandle->pTsdb->tsdbFileH->fhlock);
       tsdbDebug("%p remain files are not qualified for qrange:%" PRId64 "-%" PRId64 ", ignore, %p", pQueryHandle,
                 pQueryHandle->window.skey, pQueryHandle->window.ekey, pQueryHandle->qinfo);
       pQueryHandle->pFileGroup = NULL;
@@ -1474,6 +1472,19 @@ static int32_t getDataBlocksInFilesImpl(STsdbQueryHandle* pQueryHandle, bool* ex
       break;
     }
 
+    if (tsdbSetAndOpenHelperFile(&pQueryHandle->rhelper, pQueryHandle->pFileGroup) < 0) {
+      pthread_rwlock_unlock(&pQueryHandle->pTsdb->tsdbFileH->fhlock);
+      code = terrno;
+      break;
+    }
+
+    pthread_rwlock_unlock(&pQueryHandle->pTsdb->tsdbFileH->fhlock);
+
+    if (tsdbLoadCompIdx(&pQueryHandle->rhelper, NULL) < 0) {
+      code = terrno;
+      break;
+    }
+
     if ((code = getFileCompInfo(pQueryHandle, &numOfBlocks)) != TSDB_CODE_SUCCESS) {
       break;
     }
@@ -1528,8 +1539,10 @@ static int32_t getDataBlocksInFiles(STsdbQueryHandle* pQueryHandle, bool* exists
     STsdbCfg* pCfg = &pQueryHandle->pTsdb->config;
     int32_t fid = getFileIdFromKey(pQueryHandle->window.skey, pCfg->daysPerFile, pCfg->precision);
 
+    pthread_rwlock_rdlock(&pQueryHandle->pTsdb->tsdbFileH->fhlock);
     tsdbInitFileGroupIter(pFileHandle, &pQueryHandle->fileIter, pQueryHandle->order);
     tsdbSeekFileGroupIter(&pQueryHandle->fileIter, fid);
+    pthread_rwlock_unlock(&pQueryHandle->pTsdb->tsdbFileH->fhlock);
 
     return getDataBlocksInFilesImpl(pQueryHandle, exists);
   } else {