diff --git a/source/dnode/mnode/impl/src/mndSync.c b/source/dnode/mnode/impl/src/mndSync.c
index debc088384..36b6b6e5e4 100644
--- a/source/dnode/mnode/impl/src/mndSync.c
+++ b/source/dnode/mnode/impl/src/mndSync.c
@@ -71,33 +71,28 @@ int32_t mndSnapshotRead(struct SSyncFSM *pFsm, const SSnapshot *pSnapshot, void
   SMnode *pMnode = pFsm->data;
   mInfo("start to read snapshot from sdb");
 
-  int32_t code = sdbReadSnapshot(pMnode->pSdb, (SSdbIter **)ppIter, (void**)ppBuf, len);
-  if (code != 0) {
-    mError("failed to read snapshot from sdb since %s", terrstr());
-  } else {
-    if (*ppIter == NULL) {
-      mInfo("successfully to read snapshot from sdb");
-    }
-  }
+  // sdbStartRead
+  // sdbDoRead
+  // sdbStopRead
 
-  return code;
+  return 0;
 }
 
 int32_t mndSnapshotApply(struct SSyncFSM *pFsm, const SSnapshot *pSnapshot, char *pBuf, int32_t len) {
   SMnode *pMnode = pFsm->data;
-  mndSetRestore(pMnode, false);
-  mInfo("start to apply snapshot to sdb, len:%d", len);
 
-  int32_t code = sdbApplySnapshot(pMnode->pSdb, pBuf, len);
-  if (code != 0) {
-    mError("failed to apply snapshot to sdb, len:%d", len);
-  } else {
-    mInfo("successfully to apply snapshot to sdb, len:%d", len);
-    mndSetRestore(pMnode, true);
-  }
+  // sdbStartWrite
+  // sdbDoWrite
+
+  mndSetRestore(pMnode, false);
+  mInfo("start to apply snapshot to sdb");
+
+  // sdbStopWrite
+  mInfo("successfully to apply snapshot to sdb");
+  mndSetRestore(pMnode, true);
 
   // taosMemoryFree(pBuf);
-  return code;
+  return 0;
 }
 
 void mndReConfig(struct SSyncFSM *pFsm, SSyncCfg newCfg, SReConfigCbMeta cbMeta) {
diff --git a/source/dnode/mnode/impl/test/sdb/sdbTest.cpp b/source/dnode/mnode/impl/test/sdb/sdbTest.cpp
index 80a5786853..43be55dd1d 100644
--- a/source/dnode/mnode/impl/test/sdb/sdbTest.cpp
+++ b/source/dnode/mnode/impl/test/sdb/sdbTest.cpp
@@ -492,7 +492,7 @@ TEST_F(MndTestSdb, 01_Write_Str) {
 
   ASSERT_EQ(sdbGetSize(pSdb, SDB_USER), 2);
   ASSERT_EQ(sdbGetMaxId(pSdb, SDB_USER), -1);
-  ASSERT_EQ(sdbGetTableVer(pSdb, SDB_USER), 2 );
+  ASSERT_EQ(sdbGetTableVer(pSdb, SDB_USER), 2);
   sdbSetApplyIndex(pSdb, -1);
   ASSERT_EQ(sdbGetApplyIndex(pSdb), -1);
   ASSERT_EQ(mnode.insertTimes, 2);
@@ -896,21 +896,28 @@ TEST_F(MndTestSdb, 01_Read_Str) {
   }
 
   {
-    void     *sdbbuf = taosMemoryMalloc(1024 * 1024);
-    int32_t total = 0;
+    SSdbIter *pReader = NULL;
+    SSdbIter *pWritter = NULL;
     void     *pBuf = NULL;
     int32_t   len = 0;
-    SSdbIter *pIter = NULL;
-    while (sdbReadSnapshot(pSdb, &pIter, &pBuf, &len) == 0) {
+    int32_t   code = 0;
+
+    code = sdbStartRead(pSdb, &pReader);
+    ASSERT_EQ(code, 0);
+    code = sdbStartWrite(pSdb, &pWritter);
+    ASSERT_EQ(code, 0);
+
+    while (sdbDoRead(pSdb, pReader, &pBuf, &len) == 0) {
       if (pBuf != NULL && len != 0) {
-        memcpy((char *)sdbbuf + total, pBuf, len);
-        total += len;
+        sdbDoWrite(pSdb, pWritter, pBuf, len);
         taosMemoryFree(pBuf);
       } else {
         break;
       }
     }
-    sdbApplySnapshot(pSdb, sdbbuf, total);
+
+    sdbStopRead(pSdb, pReader);
+    sdbStopWrite(pSdb, pWritter, true);
   }
 
   ASSERT_EQ(sdbGetSize(pSdb, SDB_CONSUMER), 1);
diff --git a/source/dnode/mnode/sdb/inc/sdb.h b/source/dnode/mnode/sdb/inc/sdb.h
index b34b8684a6..c66b47a24b 100644
--- a/source/dnode/mnode/sdb/inc/sdb.h
+++ b/source/dnode/mnode/sdb/inc/sdb.h
@@ -187,6 +187,7 @@ typedef struct SSdb {
 typedef struct SSdbIter {
   TdFilePtr file;
   int64_t   total;
+  char     *name;
 } SSdbIter;
 
 typedef struct {
@@ -380,8 +381,13 @@ SSdbRow *sdbAllocRow(int32_t objSize);
 void    *sdbGetRowObj(SSdbRow *pRow);
 void     sdbFreeRow(SSdb *pSdb, SSdbRow *pRow, bool callFunc);
 
-int32_t sdbReadSnapshot(SSdb *pSdb, SSdbIter **ppIter, void **ppBuf, int32_t *len);
-int32_t sdbApplySnapshot(SSdb *pSdb, void *pBuf, int32_t len);
+int32_t sdbStartRead(SSdb *pSdb, SSdbIter **ppIter);
+int32_t sdbStopRead(SSdb *pSdb, SSdbIter *pIter);
+int32_t sdbDoRead(SSdb *pSdb, SSdbIter *pIter, void **ppBuf, int32_t *len);
+
+int32_t sdbStartWrite(SSdb *pSdb, SSdbIter **ppIter);
+int32_t sdbStopWrite(SSdb *pSdb, SSdbIter *pIter, bool isApply);
+int32_t sdbDoWrite(SSdb *pSdb, SSdbIter *pIter, void *pBuf, int32_t len);
 
 const char *sdbTableName(ESdbType type);
 void        sdbPrintOper(SSdb *pSdb, SSdbRow *pRow, const char *oper);
diff --git a/source/dnode/mnode/sdb/src/sdb.c b/source/dnode/mnode/sdb/src/sdb.c
index aef3476440..485b729deb 100644
--- a/source/dnode/mnode/sdb/src/sdb.c
+++ b/source/dnode/mnode/sdb/src/sdb.c
@@ -71,6 +71,7 @@ void sdbCleanup(SSdb *pSdb) {
   }
 
   if (pSdb->tmpDir != NULL) {
+    taosRemoveDir(pSdb->tmpDir);
     taosMemoryFreeClear(pSdb->tmpDir);
   }
 
diff --git a/source/dnode/mnode/sdb/src/sdbFile.c b/source/dnode/mnode/sdb/src/sdbFile.c
index 6891f94244..1ca5097ce6 100644
--- a/source/dnode/mnode/sdb/src/sdbFile.c
+++ b/source/dnode/mnode/sdb/src/sdbFile.c
@@ -445,82 +445,84 @@ int32_t sdbDeploy(SSdb *pSdb) {
   return 0;
 }
 
-static SSdbIter *sdbOpenIter(SSdb *pSdb) {
-  char datafile[PATH_MAX] = {0};
-  char tmpfile[PATH_MAX] = {0};
-  snprintf(datafile, sizeof(datafile), "%s%ssdb.data", pSdb->currDir, TD_DIRSEP);
-  snprintf(tmpfile, sizeof(tmpfile), "%s%ssdb.data", pSdb->tmpDir, TD_DIRSEP);
-
-  taosThreadMutexLock(&pSdb->filelock);
-  if (taosCopyFile(datafile, tmpfile) < 0) {
-    taosThreadMutexUnlock(&pSdb->filelock);
-    terrno = TAOS_SYSTEM_ERROR(errno);
-    mError("failed to copy file %s to %s since %s", datafile, tmpfile, terrstr());
-    return NULL;
-  }
-  taosThreadMutexUnlock(&pSdb->filelock);
-
+static SSdbIter *sdbCreateIter(SSdb *pSdb) {
   SSdbIter *pIter = taosMemoryCalloc(1, sizeof(SSdbIter));
   if (pIter == NULL) {
     terrno = TSDB_CODE_OUT_OF_MEMORY;
     return NULL;
   }
 
-  pIter->file = taosOpenFile(tmpfile, TD_FILE_READ);
-  if (pIter->file == NULL) {
-    terrno = TAOS_SYSTEM_ERROR(errno);
-    mError("failed to read file:%s since %s", tmpfile, terrstr());
+  char name[PATH_MAX + 100] = {0};
+  snprintf(name, sizeof(name), "%s%ssdb.data.%" PRIu64, pSdb->tmpDir, TD_DIRSEP, (uint64_t)pIter);
+  pIter->name = strdup(name);
+  if (pIter->name == NULL) {
     taosMemoryFree(pIter);
+    terrno = TSDB_CODE_OUT_OF_MEMORY;
     return NULL;
   }
 
   return pIter;
 }
 
-static void sdbCloseIter(SSdb *pSdb, SSdbIter *pIter) {
+static void sdbCloseIter(SSdbIter *pIter) {
   if (pIter == NULL) return;
+
   if (pIter->file != NULL) {
     taosCloseFile(&pIter->file);
+    pIter->file = NULL;
   }
 
-  char tmpfile[PATH_MAX] = {0};
-  snprintf(tmpfile, sizeof(tmpfile), "%s%ssdb.data", pSdb->tmpDir, TD_DIRSEP);
-  taosRemoveFile(tmpfile);
+  if (pIter->name != NULL) {
+    taosRemoveFile(pIter->name);
+    taosMemoryFree(pIter->name);
+    pIter->name = NULL;
+  }
 
+  mInfo("sdbiter:%p, is closed, total:%" PRId64, pIter, pIter->total);
   taosMemoryFree(pIter);
-  mInfo("sdbiter:%p, is closed", pIter);
 }
 
-static SSdbIter *sdbGetIter(SSdb *pSdb, SSdbIter **ppIter) {
-  SSdbIter *pIter = NULL;
-  if (ppIter != NULL) pIter = *ppIter;
-
-  if (pIter == NULL) {
-    pIter = sdbOpenIter(pSdb);
-    if (pIter != NULL) {
-      mInfo("sdbiter:%p, is created to read snapshot", pIter);
-      *ppIter = pIter;
-    } else {
-      mError("failed to create sdbiter to read snapshot since %s", terrstr());
-      *ppIter = NULL;
-      return NULL;
-    }
-  } else {
-    mInfo("sdbiter:%p, continue to read snapshot, total:%" PRId64, pIter, pIter->total);
-  }
-
-  return pIter;
-}
-
-int32_t sdbReadSnapshot(SSdb *pSdb, SSdbIter **ppIter, void **ppBuf, int32_t *len) {
-  SSdbIter *pIter = sdbGetIter(pSdb, ppIter);
+int32_t sdbStartRead(SSdb *pSdb, SSdbIter **ppIter) {
+  SSdbIter *pIter = sdbCreateIter(pSdb);
   if (pIter == NULL) return -1;
 
+  char datafile[PATH_MAX] = {0};
+  snprintf(datafile, sizeof(datafile), "%s%ssdb.data", pSdb->currDir, TD_DIRSEP);
+
+  taosThreadMutexLock(&pSdb->filelock);
+  if (taosCopyFile(datafile, pIter->name) < 0) {
+    taosThreadMutexUnlock(&pSdb->filelock);
+    terrno = TAOS_SYSTEM_ERROR(errno);
+    mError("failed to copy file %s to %s since %s", datafile, pIter->name, terrstr());
+    sdbCloseIter(pIter);
+    return -1;
+  }
+  taosThreadMutexUnlock(&pSdb->filelock);
+
+  pIter->file = taosOpenFile(pIter->name, TD_FILE_READ);
+  if (pIter->file == NULL) {
+    terrno = TAOS_SYSTEM_ERROR(errno);
+    mError("failed to open file:%s since %s", pIter->name, terrstr());
+    sdbCloseIter(pIter);
+    return -1;
+  }
+
+  *ppIter = pIter;
+  mInfo("sdbiter:%p, is created to read snapshot, file:%s", pIter, pIter->name);
+  return 0;
+}
+
+int32_t sdbStopRead(SSdb *pSdb, SSdbIter *pIter) {
+  sdbCloseIter(pIter);
+  return 0;
+}
+
+int32_t sdbDoRead(SSdb *pSdb, SSdbIter *pIter, void **ppBuf, int32_t *len) {
   int32_t maxlen = 100;
   void   *pBuf = taosMemoryCalloc(1, maxlen);
   if (pBuf == NULL) {
     terrno = TSDB_CODE_OUT_OF_MEMORY;
-    sdbCloseIter(pSdb, pIter);
+    sdbCloseIter(pIter);
     return -1;
   }
 
@@ -530,17 +532,12 @@ int32_t sdbReadSnapshot(SSdb *pSdb, SSdbIter **ppIter, void **ppBuf, int32_t *le
     mError("sdbiter:%p, failed to read snapshot since %s, total:%" PRId64, pIter, terrstr(), pIter->total);
     *ppBuf = NULL;
     *len = 0;
-    *ppIter = NULL;
-    sdbCloseIter(pSdb, pIter);
     taosMemoryFree(pBuf);
     return -1;
   } else if (readlen == 0) {
     mInfo("sdbiter:%p, read snapshot to the end, total:%" PRId64, pIter, pIter->total);
     *ppBuf = NULL;
     *len = 0;
-    *ppIter = NULL;
-    *ppIter = NULL;
-    sdbCloseIter(pSdb, pIter);
     taosMemoryFree(pBuf);
     return 0;
   } else {  // (readlen <= maxlen)
@@ -552,46 +549,63 @@ int32_t sdbReadSnapshot(SSdb *pSdb, SSdbIter **ppIter, void **ppBuf, int32_t *le
   }
 }
 
-int32_t sdbApplySnapshot(SSdb *pSdb, void *pBuf, int32_t len) {
-  char datafile[PATH_MAX] = {0};
-  char tmpfile[PATH_MAX] = {0};
-  snprintf(datafile, sizeof(datafile), "%s%ssdb.data", pSdb->currDir, TD_DIRSEP);
-  snprintf(tmpfile, sizeof(tmpfile), "%s%ssdb.data", pSdb->tmpDir, TD_DIRSEP);
+int32_t sdbStartWrite(SSdb *pSdb, SSdbIter **ppIter) {
+  SSdbIter *pIter = sdbCreateIter(pSdb);
+  if (pIter == NULL) return -1;
 
-  TdFilePtr pFile = taosOpenFile(tmpfile, TD_FILE_CREATE | TD_FILE_WRITE | TD_FILE_TRUNC);
-  if (pFile == NULL) {
+  pIter->file = taosOpenFile(pIter->name, TD_FILE_CREATE | TD_FILE_WRITE | TD_FILE_TRUNC);
+  if (pIter->file == NULL) {
     terrno = TAOS_SYSTEM_ERROR(errno);
-    mError("failed to write %s since %s", tmpfile, terrstr());
+    mError("failed to open %s since %s", pIter->name, terrstr());
     return -1;
   }
 
-  int32_t writelen = taosWriteFile(pFile, pBuf, len);
+  *ppIter = pIter;
+  mInfo("sdbiter:%p, is created to write snapshot, file:%s", pIter, pIter->name);
+  return 0;
+}
+
+int32_t sdbStopWrite(SSdb *pSdb, SSdbIter *pIter, bool isApply) {
+  int32_t code = 0;
+
+  if (!isApply) {
+    sdbCloseIter(pIter);
+    mInfo("sdbiter:%p, not apply to sdb", pIter);
+    return 0;
+  }
+
+  taosFsyncFile(pIter->file);
+  taosCloseFile(&pIter->file);
+  pIter->file = NULL;
+
+  char datafile[PATH_MAX] = {0};
+  snprintf(datafile, sizeof(datafile), "%s%ssdb.data", pSdb->currDir, TD_DIRSEP);
+  if (taosRenameFile(pIter->name, datafile) != 0) {
+    terrno = TAOS_SYSTEM_ERROR(errno);
+    mError("sdbiter:%p, failed to rename file %s to %s since %s", pIter, pIter->name, datafile, terrstr());
+    sdbCloseIter(pIter);
+    return -1;
+  }
+
+  sdbCloseIter(pIter);
+  if (sdbReadFile(pSdb) != 0) {
+    mError("sdbiter:%p, failed to read from %s since %s", pIter, datafile, terrstr());
+    return -1;
+  }
+
+  mInfo("sdbiter:%p, successfully applyed to sdb", pIter);
+  return 0;
+}
+
+int32_t sdbDoWrite(SSdb *pSdb, SSdbIter *pIter, void *pBuf, int32_t len) {
+  int32_t writelen = taosWriteFile(pIter->file, pBuf, len);
   if (writelen != len) {
     terrno = TAOS_SYSTEM_ERROR(errno);
-    mError("failed to write %s since %s", tmpfile, terrstr());
-    taosCloseFile(&pFile);
-    return -1;
-  }
-
-  if (taosFsyncFile(pFile) != 0) {
-    terrno = TAOS_SYSTEM_ERROR(errno);
-    mError("failed to fsync %s since %s", tmpfile, terrstr());
-    taosCloseFile(&pFile);
-    return -1;
-  }
-
-  (void)taosCloseFile(&pFile);
-
-  if (taosRenameFile(tmpfile, datafile) != 0) {
-    terrno = TAOS_SYSTEM_ERROR(errno);
-    mError("failed to rename file %s to %s since %s", tmpfile, datafile, terrstr());
-    return -1;
-  }
-
-  if (sdbReadFile(pSdb) != 0) {
-    mError("failed to read from %s since %s", datafile, terrstr());
+    mError("failed to write len:%d since %s, total:%" PRId64, len, terrstr(), pIter->total);
     return -1;
   }
 
+  pIter->total += writelen;
+  mInfo("sdbiter:%p, write:%d bytes to snapshot, total:%" PRId64, pIter, writelen, pIter->total);
   return 0;
 }
\ No newline at end of file