diff --git a/source/dnode/mnode/impl/src/mndSync.c b/source/dnode/mnode/impl/src/mndSync.c
index c6ab916ee1..debc088384 100644
--- a/source/dnode/mnode/impl/src/mndSync.c
+++ b/source/dnode/mnode/impl/src/mndSync.c
@@ -71,7 +71,7 @@ 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, ppBuf, len);
+  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 {
diff --git a/source/dnode/mnode/impl/test/sdb/sdbTest.cpp b/source/dnode/mnode/impl/test/sdb/sdbTest.cpp
index df535c4456..80a5786853 100644
--- a/source/dnode/mnode/impl/test/sdb/sdbTest.cpp
+++ b/source/dnode/mnode/impl/test/sdb/sdbTest.cpp
@@ -895,7 +895,28 @@ TEST_F(MndTestSdb, 01_Read_Str) {
     ASSERT_EQ(code, TSDB_CODE_SDB_OBJ_CREATING);
   }
 
+  {
+    void     *sdbbuf = taosMemoryMalloc(1024 * 1024);
+    int32_t total = 0;
+    void     *pBuf = NULL;
+    int32_t   len = 0;
+    SSdbIter *pIter = NULL;
+    while (sdbReadSnapshot(pSdb, &pIter, &pBuf, &len) == 0) {
+      if (pBuf != NULL && len != 0) {
+        memcpy((char *)sdbbuf + total, pBuf, len);
+        total += len;
+        taosMemoryFree(pBuf);
+      } else {
+        break;
+      }
+    }
+    sdbApplySnapshot(pSdb, sdbbuf, total);
+  }
+
+  ASSERT_EQ(sdbGetSize(pSdb, SDB_CONSUMER), 1);
+  ASSERT_EQ(sdbGetTableVer(pSdb, SDB_CONSUMER), 4);
+
   sdbCleanup(pSdb);
-  ASSERT_EQ(mnode.insertTimes, 5);
-  ASSERT_EQ(mnode.deleteTimes, 5);
+  ASSERT_EQ(mnode.insertTimes, 9);
+  ASSERT_EQ(mnode.deleteTimes, 9);
 }
\ No newline at end of file
diff --git a/source/dnode/mnode/sdb/inc/sdb.h b/source/dnode/mnode/sdb/inc/sdb.h
index 411d4c59ea..b34b8684a6 100644
--- a/source/dnode/mnode/sdb/inc/sdb.h
+++ b/source/dnode/mnode/sdb/inc/sdb.h
@@ -380,8 +380,8 @@ SSdbRow *sdbAllocRow(int32_t objSize);
 void    *sdbGetRowObj(SSdbRow *pRow);
 void     sdbFreeRow(SSdb *pSdb, SSdbRow *pRow, bool callFunc);
 
-int32_t sdbReadSnapshot(SSdb *pSdb, SSdbIter **ppIter, char **ppBuf, int32_t *len);
-int32_t sdbApplySnapshot(SSdb *pSdb, char *pBuf, int32_t len);
+int32_t sdbReadSnapshot(SSdb *pSdb, SSdbIter **ppIter, void **ppBuf, int32_t *len);
+int32_t sdbApplySnapshot(SSdb *pSdb, 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/sdbFile.c b/source/dnode/mnode/sdb/src/sdbFile.c
index b2dcbd68e3..6891f94244 100644
--- a/source/dnode/mnode/sdb/src/sdbFile.c
+++ b/source/dnode/mnode/sdb/src/sdbFile.c
@@ -452,7 +452,7 @@ static SSdbIter *sdbOpenIter(SSdb *pSdb) {
   snprintf(tmpfile, sizeof(tmpfile), "%s%ssdb.data", pSdb->tmpDir, TD_DIRSEP);
 
   taosThreadMutexLock(&pSdb->filelock);
-  if (taosCopyFile(datafile, tmpfile) != 0) {
+  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());
@@ -512,12 +512,12 @@ static SSdbIter *sdbGetIter(SSdb *pSdb, SSdbIter **ppIter) {
   return pIter;
 }
 
-int32_t sdbReadSnapshot(SSdb *pSdb, SSdbIter **ppIter, char **ppBuf, int32_t *len) {
+int32_t sdbReadSnapshot(SSdb *pSdb, SSdbIter **ppIter, void **ppBuf, int32_t *len) {
   SSdbIter *pIter = sdbGetIter(pSdb, ppIter);
   if (pIter == NULL) return -1;
 
   int32_t maxlen = 100;
-  char   *pBuf = taosMemoryCalloc(1, maxlen);
+  void   *pBuf = taosMemoryCalloc(1, maxlen);
   if (pBuf == NULL) {
     terrno = TSDB_CODE_OUT_OF_MEMORY;
     sdbCloseIter(pSdb, pIter);
@@ -525,7 +525,7 @@ int32_t sdbReadSnapshot(SSdb *pSdb, SSdbIter **ppIter, char **ppBuf, int32_t *le
   }
 
   int32_t readlen = taosReadFile(pIter->file, pBuf, maxlen);
-  if (readlen < 0 || (readlen == 0 && errno != 0)) {
+  if (readlen < 0 || readlen > maxlen) {
     terrno = TAOS_SYSTEM_ERROR(errno);
     mError("sdbiter:%p, failed to read snapshot since %s, total:%" PRId64, pIter, terrstr(), pIter->total);
     *ppBuf = NULL;
@@ -539,35 +539,20 @@ int32_t sdbReadSnapshot(SSdb *pSdb, SSdbIter **ppIter, char **ppBuf, int32_t *le
     *ppBuf = NULL;
     *len = 0;
     *ppIter = NULL;
+    *ppIter = NULL;
     sdbCloseIter(pSdb, pIter);
     taosMemoryFree(pBuf);
     return 0;
-  } else if ((readlen < maxlen && errno != 0) || readlen == maxlen) {
+  } else {  // (readlen <= maxlen)
     pIter->total += readlen;
     mInfo("sdbiter:%p, read:%d bytes from snapshot, total:%" PRId64, pIter, readlen, pIter->total);
     *ppBuf = pBuf;
     *len = readlen;
     return 0;
-  } else if (readlen < maxlen && errno == 0) {
-    mInfo("sdbiter:%p, read snapshot to the end, total:%" PRId64, pIter, pIter->total);
-    *ppBuf = pBuf;
-    *len = readlen;
-    *ppIter = NULL;
-    sdbCloseIter(pSdb, pIter);
-    return 0;
-  } else {
-    // impossible
-    mError("sdbiter:%p, read:%d bytes from snapshot, total:%" PRId64, pIter, readlen, pIter->total);
-    *ppBuf = NULL;
-    *len = 0;
-    *ppIter = NULL;
-    sdbCloseIter(pSdb, pIter);
-    taosMemoryFree(pBuf);
-    return -1;
   }
 }
 
-int32_t sdbApplySnapshot(SSdb *pSdb, char *pBuf, int32_t len) {
+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);