diff --git a/source/dnode/vnode/src/inc/tsdb.h b/source/dnode/vnode/src/inc/tsdb.h
index b0cf6ecf5b..a5203353db 100644
--- a/source/dnode/vnode/src/inc/tsdb.h
+++ b/source/dnode/vnode/src/inc/tsdb.h
@@ -690,12 +690,12 @@ int32_t tsdbTFileSetRangeArrayDestroy(TFileSetRangeArray **ppArr);
 
 // fset partition
 enum {
-  TSDB_SNAP_RANGE_TYP_HEAD = 0,
-  TSDB_SNAP_RANGE_TYP_DATA,
-  TSDB_SNAP_RANGE_TYP_SMA,
-  TSDB_SNAP_RANGE_TYP_TOMB,
-  TSDB_SNAP_RANGE_TYP_STT,
-  TSDB_SNAP_RANGE_TYP_MAX,
+  TSDB_FSET_RANGE_TYP_HEAD = 0,
+  TSDB_FSET_RANGE_TYP_DATA,
+  TSDB_FSET_RANGE_TYP_SMA,
+  TSDB_FSET_RANGE_TYP_TOMB,
+  TSDB_FSET_RANGE_TYP_STT,
+  TSDB_FSET_RANGE_TYP_MAX,
 };
 
 typedef TARRAY2(SVersionRange) SVerRangeList;
@@ -703,7 +703,7 @@ typedef TARRAY2(SVersionRange) SVerRangeList;
 struct STsdbFSetPartition {
   int64_t       fid;
   int8_t        stat;
-  SVerRangeList verRanges[TSDB_SNAP_RANGE_TYP_MAX];
+  SVerRangeList verRanges[TSDB_FSET_RANGE_TYP_MAX];
 };
 
 typedef struct STsdbFSetPartition STsdbFSetPartition;
diff --git a/source/dnode/vnode/src/tsdb/tsdbSnapInfo.c b/source/dnode/vnode/src/tsdb/tsdbSnapInfo.c
index 9d741ab2d3..8afbe187a4 100644
--- a/source/dnode/vnode/src/tsdb/tsdbSnapInfo.c
+++ b/source/dnode/vnode/src/tsdb/tsdbSnapInfo.c
@@ -31,7 +31,7 @@ static int32_t tVersionRangeCmprFn(SVersionRange* x, SVersionRange* y) {
   return 0;
 }
 
-static int32_t tsdbFileSetRangeCmprFn(STFileSetRange* x, STFileSetRange* y) {
+static int32_t tsdbTFileSetRangeCmprFn(STFileSetRange* x, STFileSetRange* y) {
   if (x->fid < y->fid) return -1;
   if (x->fid > y->fid) return 1;
   return 0;
@@ -43,7 +43,7 @@ STsdbFSetPartition* tsdbFSetPartitionCreate() {
     terrno = TSDB_CODE_OUT_OF_MEMORY;
     return NULL;
   }
-  for (int32_t i = 0; i < TSDB_SNAP_RANGE_TYP_MAX; i++) {
+  for (int32_t i = 0; i < TSDB_FSET_RANGE_TYP_MAX; i++) {
     TARRAY2_INIT(&pSP->verRanges[i]);
   }
   return pSP;
@@ -53,30 +53,30 @@ void tsdbFSetPartitionClear(STsdbFSetPartition** ppSP) {
   if (ppSP == NULL || ppSP[0] == NULL) {
     return;
   }
-  for (int32_t i = 0; i < TSDB_SNAP_RANGE_TYP_MAX; i++) {
+  for (int32_t i = 0; i < TSDB_FSET_RANGE_TYP_MAX; i++) {
     TARRAY2_DESTROY(&ppSP[0]->verRanges[i], NULL);
   }
   taosMemoryFree(ppSP[0]);
   ppSP[0] = NULL;
 }
 
-static int32_t tsdbFTypeToSRangeTyp(tsdb_ftype_t ftype) {
+static int32_t tsdbFTypeToFRangeType(tsdb_ftype_t ftype) {
   switch (ftype) {
     case TSDB_FTYPE_HEAD:
-      return TSDB_SNAP_RANGE_TYP_HEAD;
+      return TSDB_FSET_RANGE_TYP_HEAD;
     case TSDB_FTYPE_DATA:
-      return TSDB_SNAP_RANGE_TYP_DATA;
+      return TSDB_FSET_RANGE_TYP_DATA;
     case TSDB_FTYPE_SMA:
-      return TSDB_SNAP_RANGE_TYP_SMA;
+      return TSDB_FSET_RANGE_TYP_SMA;
     case TSDB_FTYPE_TOMB:
-      return TSDB_SNAP_RANGE_TYP_TOMB;
+      return TSDB_FSET_RANGE_TYP_TOMB;
     case TSDB_FTYPE_STT:
-      return TSDB_SNAP_RANGE_TYP_STT;
+      return TSDB_FSET_RANGE_TYP_STT;
   }
-  return TSDB_SNAP_RANGE_TYP_MAX;
+  return TSDB_FSET_RANGE_TYP_MAX;
 }
 
-static int32_t tsdbTFileSetToSnapPart(STFileSet* fset, STsdbFSetPartition** ppSP) {
+static int32_t tsdbTFileSetToFSetPartition(STFileSet* fset, STsdbFSetPartition** ppSP) {
   STsdbFSetPartition* p = tsdbFSetPartitionCreate();
   if (p == NULL) {
     goto _err;
@@ -90,8 +90,8 @@ static int32_t tsdbTFileSetToSnapPart(STFileSet* fset, STsdbFSetPartition** ppSP
   int32_t count = 0;
   for (int32_t ftype = TSDB_FTYPE_MIN; ftype < TSDB_FTYPE_MAX; ++ftype) {
     if (fset->farr[ftype] == NULL) continue;
-    typ = tsdbFTypeToSRangeTyp(ftype);
-    ASSERT(typ < TSDB_SNAP_RANGE_TYP_MAX);
+    typ = tsdbFTypeToFRangeType(ftype);
+    ASSERT(typ < TSDB_FSET_RANGE_TYP_MAX);
     STFile* f = fset->farr[ftype]->f;
     if (f->maxVer > fset->maxVerValid) {
       corrupt = true;
@@ -106,7 +106,7 @@ static int32_t tsdbTFileSetToSnapPart(STFileSet* fset, STsdbFSetPartition** ppSP
     ASSERT(code == 0);
   }
 
-  typ = TSDB_SNAP_RANGE_TYP_STT;
+  typ = TSDB_FSET_RANGE_TYP_STT;
   const SSttLvl* lvl;
   TARRAY2_FOREACH(fset->lvlArr, lvl) {
     STFileObj* fobj;
@@ -149,35 +149,61 @@ STsdbFSetPartList* tsdbFSetPartListCreate() {
   return pList;
 }
 
-static STsdbFSetPartList* tsdbGetSnapPartList(STFileSystem* fs) {
-  STsdbFSetPartList* pList = tsdbFSetPartListCreate();
-  if (pList == NULL) {
-    return NULL;
-  }
+void tsdbFSetPartListDestroy(STsdbFSetPartList** ppList) {
+  if (ppList == NULL || ppList[0] == NULL) return;
 
-  int32_t code = 0;
-  taosThreadMutexLock(&fs->tsdb->mutex);
-  STFileSet* fset;
-  TARRAY2_FOREACH(fs->fSetArr, fset) {
-    STsdbFSetPartition* pItem = NULL;
-    if (tsdbTFileSetToSnapPart(fset, &pItem) < 0) {
-      code = -1;
-      break;
-    }
-    ASSERT(pItem != NULL);
-    code = TARRAY2_SORT_INSERT(pList, pItem, tsdbFSetPartCmprFn);
-    ASSERT(code == 0);
-  }
-  taosThreadMutexUnlock(&fs->tsdb->mutex);
-
-  if (code) {
-    TARRAY2_DESTROY(pList, tsdbFSetPartitionClear);
-    taosMemoryFree(pList);
-    pList = NULL;
-  }
-  return pList;
+  TARRAY2_DESTROY(ppList[0], tsdbFSetPartitionClear);
+  taosMemoryFree(ppList[0]);
+  ppList[0] = NULL;
 }
 
+int32_t tsdbFSetPartListToRangeDiff(STsdbFSetPartList* pList, TFileSetRangeArray** ppRanges) {
+  TFileSetRangeArray* pDiff = taosMemoryCalloc(1, sizeof(TFileSetRangeArray));
+  if (pDiff == NULL) {
+    terrno = TSDB_CODE_OUT_OF_MEMORY;
+    goto _err;
+  }
+  TARRAY2_INIT(pDiff);
+
+  STsdbFSetPartition* part;
+  TARRAY2_FOREACH(pList, part) {
+    STFileSetRange* r = taosMemoryCalloc(1, sizeof(STFileSetRange));
+    if (r == NULL) {
+      terrno = TSDB_CODE_OUT_OF_MEMORY;
+      goto _err;
+    }
+    int64_t maxVerValid = -1;
+    int32_t typMax = TSDB_FSET_RANGE_TYP_MAX;
+    for (int32_t i = 0; i < typMax; i++) {
+      SVerRangeList* iList = &part->verRanges[i];
+      SVersionRange  vr = {0};
+      TARRAY2_FOREACH(iList, vr) {
+        if (vr.maxVer < vr.minVer) {
+          continue;
+        }
+        maxVerValid = TMAX(maxVerValid, vr.maxVer);
+      }
+    }
+    r->fid = part->fid;
+    r->sver = maxVerValid + 1;
+    r->ever = VERSION_MAX;
+    tsdbDebug("range diff fid:%" PRId64 ", sver:%" PRId64 ", ever:%" PRId64, part->fid, r->sver, r->ever);
+    int32_t code = TARRAY2_SORT_INSERT(pDiff, r, tsdbTFileSetRangeCmprFn);
+    ASSERT(code == 0);
+  }
+  ppRanges[0] = pDiff;
+
+  tsdbInfo("pDiff size:%d", TARRAY2_SIZE(pDiff));
+  return 0;
+
+_err:
+  if (pDiff) {
+    tsdbTFileSetRangeArrayDestroy(&pDiff);
+  }
+  return -1;
+}
+
+// serialization
 int32_t tTsdbFSetPartListDataLenCalc(STsdbFSetPartList* pList) {
   int32_t hdrLen = sizeof(int32_t);
   int32_t datLen = 0;
@@ -190,7 +216,7 @@ int32_t tTsdbFSetPartListDataLenCalc(STsdbFSetPartList* pList) {
 
   for (int32_t u = 0; u < len; u++) {
     STsdbFSetPartition* p = TARRAY2_GET(pList, u);
-    int32_t             typMax = TSDB_SNAP_RANGE_TYP_MAX;
+    int32_t             typMax = TSDB_FSET_RANGE_TYP_MAX;
     int32_t             uItem = 0;
     uItem += sizeof(STsdbFSetPartition);
     uItem += sizeof(typMax);
@@ -229,7 +255,7 @@ int32_t tSerializeTsdbFSetPartList(void* buf, int32_t bufLen, STsdbFSetPartList*
     if (tEncodeI8(&encoder, reserved8) < 0) goto _err;
     if (tEncodeI16(&encoder, reserved16) < 0) goto _err;
 
-    int32_t typMax = TSDB_SNAP_RANGE_TYP_MAX;
+    int32_t typMax = TSDB_FSET_RANGE_TYP_MAX;
     if (tEncodeI32(&encoder, typMax) < 0) goto _err;
 
     for (int32_t i = 0; i < typMax; i++) {
@@ -311,58 +337,34 @@ _err:
   return -1;
 }
 
-int32_t tsdbFSetPartListToRangeDiff(STsdbFSetPartList* pList, TFileSetRangeArray** ppRanges) {
-  TFileSetRangeArray* pDiff = taosMemoryCalloc(1, sizeof(TFileSetRangeArray));
-  if (pDiff == NULL) {
-    terrno = TSDB_CODE_OUT_OF_MEMORY;
-    goto _err;
+// fs state
+static STsdbFSetPartList* tsdbSnapGetFSetPartList(STFileSystem* fs) {
+  STsdbFSetPartList* pList = tsdbFSetPartListCreate();
+  if (pList == NULL) {
+    return NULL;
   }
-  TARRAY2_INIT(pDiff);
 
-  STsdbFSetPartition* part;
-  TARRAY2_FOREACH(pList, part) {
-    STFileSetRange* r = taosMemoryCalloc(1, sizeof(STFileSetRange));
-    if (r == NULL) {
-      terrno = TSDB_CODE_OUT_OF_MEMORY;
-      goto _err;
+  int32_t code = 0;
+  taosThreadMutexLock(&fs->tsdb->mutex);
+  STFileSet* fset;
+  TARRAY2_FOREACH(fs->fSetArr, fset) {
+    STsdbFSetPartition* pItem = NULL;
+    if (tsdbTFileSetToFSetPartition(fset, &pItem) < 0) {
+      code = -1;
+      break;
     }
-    int64_t maxVerValid = -1;
-    int32_t typMax = TSDB_SNAP_RANGE_TYP_MAX;
-    for (int32_t i = 0; i < typMax; i++) {
-      SVerRangeList* iList = &part->verRanges[i];
-      SVersionRange  vr = {0};
-      TARRAY2_FOREACH(iList, vr) {
-        if (vr.maxVer < vr.minVer) {
-          continue;
-        }
-        maxVerValid = TMAX(maxVerValid, vr.maxVer);
-      }
-    }
-    r->fid = part->fid;
-    r->sver = maxVerValid + 1;
-    r->ever = VERSION_MAX;
-    tsdbDebug("range diff fid:%" PRId64 ", sver:%" PRId64 ", ever:%" PRId64, part->fid, r->sver, r->ever);
-    int32_t code = TARRAY2_SORT_INSERT(pDiff, r, tsdbFileSetRangeCmprFn);
+    ASSERT(pItem != NULL);
+    code = TARRAY2_SORT_INSERT(pList, pItem, tsdbFSetPartCmprFn);
     ASSERT(code == 0);
   }
-  ppRanges[0] = pDiff;
+  taosThreadMutexUnlock(&fs->tsdb->mutex);
 
-  tsdbInfo("pDiff size:%d", TARRAY2_SIZE(pDiff));
-  return 0;
-
-_err:
-  if (pDiff) {
-    tsdbTFileSetRangeArrayDestroy(&pDiff);
+  if (code) {
+    TARRAY2_DESTROY(pList, tsdbFSetPartitionClear);
+    taosMemoryFree(pList);
+    pList = NULL;
   }
-  return -1;
-}
-
-void tsdbFSetPartListDestroy(STsdbFSetPartList** ppList) {
-  if (ppList == NULL || ppList[0] == NULL) return;
-
-  TARRAY2_DESTROY(ppList[0], tsdbFSetPartitionClear);
-  taosMemoryFree(ppList[0]);
-  ppList[0] = NULL;
+  return pList;
 }
 
 ETsdbFsState tsdbSnapGetFsState(SVnode* pVnode) {
@@ -378,6 +380,7 @@ ETsdbFsState tsdbSnapGetFsState(SVnode* pVnode) {
   return TSDB_FS_STATE_NORMAL;
 }
 
+// description
 int32_t tsdbSnapGetDetails(SVnode* pVnode, SSnapshot* pSnap) {
   int                code = -1;
   int32_t            tsdbMaxCnt = (!VND_IS_RSMA(pVnode) ? 1 : TSDB_RETENTION_MAX);
@@ -387,7 +390,7 @@ int32_t tsdbSnapGetDetails(SVnode* pVnode, SSnapshot* pSnap) {
   // get part list
   for (int32_t j = 0; j < tsdbMaxCnt; ++j) {
     STsdb* pTsdb = SMA_RSMA_GET_TSDB(pVnode, j);
-    pLists[j] = tsdbGetSnapPartList(pTsdb->pFS);
+    pLists[j] = tsdbSnapGetFSetPartList(pTsdb->pFS);
     if (pLists[j] == NULL) goto _out;
   }