diff --git a/src/common/src/tdataformat.c b/src/common/src/tdataformat.c
index c01141f0d68181713455ab2f58017ec6e112f8b4..77e91acc14f852f9e55d72f13532ea68a26078c5 100644
--- a/src/common/src/tdataformat.c
+++ b/src/common/src/tdataformat.c
@@ -201,10 +201,10 @@ void dataColInit(SDataCol *pDataCol, STColumn *pCol, void **pBuf, int maxPoints)
 
   pDataCol->len = 0;
   if (pDataCol->type == TSDB_DATA_TYPE_BINARY || pDataCol->type == TSDB_DATA_TYPE_NCHAR) {
-    pDataCol->spaceSize = (sizeof(VarDataLenT) + pDataCol->bytes) * maxPoints;
     pDataCol->dataOff = (VarDataOffsetT *)(*pBuf);
-    pDataCol->pData = POINTER_SHIFT(*pBuf, TYPE_BYTES[pDataCol->type] * maxPoints);
-    *pBuf = POINTER_SHIFT(*pBuf, pDataCol->spaceSize + TYPE_BYTES[pDataCol->type] * maxPoints);
+    pDataCol->pData = POINTER_SHIFT(*pBuf, sizeof(VarDataOffsetT) * maxPoints);
+    pDataCol->spaceSize = pDataCol->bytes * maxPoints;
+    *pBuf = POINTER_SHIFT(*pBuf, pDataCol->spaceSize + sizeof(VarDataOffsetT) * maxPoints);
   } else {
     pDataCol->spaceSize = pDataCol->bytes * maxPoints;
     pDataCol->dataOff = NULL;
diff --git a/src/inc/taoserror.h b/src/inc/taoserror.h
index 5379b371ef05150af0fc02c2a9693e3f6111bd5a..ac2af757426cded4dcdab58c7245808d53a5d06e 100644
--- a/src/inc/taoserror.h
+++ b/src/inc/taoserror.h
@@ -71,6 +71,7 @@ TAOS_DEFINE_ERROR(TSDB_CODE_COM_OPS_NOT_SUPPORT,          0, 0x0100, "operations
 TAOS_DEFINE_ERROR(TSDB_CODE_COM_MEMORY_CORRUPTED,         0, 0x0101, "memory corrupted")
 TAOS_DEFINE_ERROR(TSDB_CODE_COM_OUT_OF_MEMORY,            0, 0x0102, "out of memory")
 TAOS_DEFINE_ERROR(TSDB_CODE_COM_INVALID_CFG_MSG,          0, 0x0103, "invalid config message")
+TAOS_DEFINE_ERROR(TSDB_CODE_COM_FILE_CORRUPTED,           0, 0x0104, "file is corrupted")
 
 //client
 TAOS_DEFINE_ERROR(TSDB_CODE_TSC_INVALID_SQL,              0, 0x0200, "invalid sql")
diff --git a/src/tsdb/inc/tsdbMain.h b/src/tsdb/inc/tsdbMain.h
index 5926f2f2436d123822bb93e597ae66fa04dfb827..f52022d79dbd553e333ef26e8d59b86ea871db94 100644
--- a/src/tsdb/inc/tsdbMain.h
+++ b/src/tsdb/inc/tsdbMain.h
@@ -161,7 +161,7 @@ typedef struct {
   int64_t index;
   int     numOfCacheBlocks;
   SList * memPool;
-} STsdbCachePool;
+} STsdbBufferPool;
 
 typedef struct {
   TSKEY   keyFirst;
@@ -173,7 +173,7 @@ typedef struct {
 typedef struct {
   int              cacheBlockSize;
   int              totalCacheBlocks;
-  STsdbCachePool   pool;
+  STsdbBufferPool   pool;
   STsdbCacheBlock *curBlock;
   SCacheMem *      mem;
   SCacheMem *      imem;
diff --git a/src/tsdb/src/tsdbCache.c b/src/tsdb/src/tsdbCache.c
index edc8472b34661fa616dcd352258249902e711a71..24476d89975bd420f53d7a40ac1cb6dd0c961bf0 100644
--- a/src/tsdb/src/tsdbCache.c
+++ b/src/tsdb/src/tsdbCache.c
@@ -35,7 +35,7 @@ STsdbCache *tsdbInitCache(int cacheBlockSize, int totalBlocks, TsdbRepoT *pRepo)
   pCache->totalCacheBlocks = totalBlocks;
   pCache->pRepo = pRepo;
 
-  STsdbCachePool *pPool = &(pCache->pool);
+  STsdbBufferPool *pPool = &(pCache->pool);
   pPool->index = 0;
   pPool->memPool = tdListNew(sizeof(STsdbCacheBlock *));
   if (pPool->memPool == NULL) goto _err;
@@ -106,7 +106,7 @@ static void tsdbFreeCacheMem(SCacheMem *mem) {
 }
 
 static int tsdbAllocBlockFromPool(STsdbCache *pCache) {
-  STsdbCachePool *pPool = &(pCache->pool);
+  STsdbBufferPool *pPool = &(pCache->pool);
   
   tsdbLockRepo(pCache->pRepo);
   if (listNEles(pPool->memPool) == 0) {
@@ -170,7 +170,7 @@ int tsdbAlterCacheTotalBlocks(STsdbRepo *pRepo, int totalBlocks) {
 }
 
 static int tsdbAddCacheBlockToPool(STsdbCache *pCache) {
-  STsdbCachePool *pPool = &pCache->pool;
+  STsdbBufferPool *pPool = &pCache->pool;
 
   STsdbCacheBlock *pBlock = malloc(sizeof(STsdbCacheBlock) + pCache->cacheBlockSize);
   if (pBlock == NULL) return -1;
@@ -184,7 +184,7 @@ static int tsdbAddCacheBlockToPool(STsdbCache *pCache) {
 }
 
 static int tsdbRemoveCacheBlockFromPool(STsdbCache *pCache) {
-  STsdbCachePool *pPool = &pCache->pool;
+  STsdbBufferPool *pPool = &pCache->pool;
   STsdbCacheBlock *pBlock = NULL;
 
   ASSERT(pCache->totalCacheBlocks >= 0);
diff --git a/src/tsdb/src/tsdbMetaFile.c b/src/tsdb/src/tsdbMetaFile.c
index 19fcae94e367816d01aa3cb29dd2f05890c3769d..921db8674aff5dd4463c122e277adb76d09fe9b1 100644
--- a/src/tsdb/src/tsdbMetaFile.c
+++ b/src/tsdb/src/tsdbMetaFile.c
@@ -105,7 +105,7 @@ int32_t tsdbInsertMetaRecord(SMetaFile *mfh, uint64_t uid, void *cont, int32_t c
     return -1;
   }
 
-  fsync(mfh->fd);
+  // fsync(mfh->fd);
 
   mfh->tombSize++;
 
@@ -132,7 +132,7 @@ int32_t tsdbDeleteMetaRecord(SMetaFile *mfh, uint64_t uid) {
     return -1;
   }
 
-  fsync(mfh->fd);
+  // fsync(mfh->fd);
 
   mfh->nDel++;
 
@@ -167,7 +167,7 @@ int32_t tsdbUpdateMetaRecord(SMetaFile *mfh, uint64_t uid, void *cont, int32_t c
     return -1;
   }
 
-  fsync(mfh->fd);
+  // fsync(mfh->fd);
 
   return 0;
 }
diff --git a/src/util/inc/tkvstore.h b/src/util/inc/tkvstore.h
index 724c94e21dde790cd0fef007d33f029e1e10f1d8..a57d0e95cfe65048a90356677a021e698ee2daaa 100644
--- a/src/util/inc/tkvstore.h
+++ b/src/util/inc/tkvstore.h
@@ -46,11 +46,12 @@ typedef struct {
 } SKVStore;
 
 int       tdCreateKVStore(char *fname);
-int       tdDestroyKVStore();
+int       tdDestroyKVStore(char *fname);
 SKVStore *tdOpenKVStore(char *fname, iterFunc iFunc, afterFunc aFunc, void *appH);
 void      tdCloseKVStore(SKVStore *pStore);
 int       tdKVStoreStartCommit(SKVStore *pStore);
-int       tdUpdateRecordInKVStore(SKVStore *pStore, uint64_t uid, void *cont, int contLen);
+int       tdUpdateKVStoreRecord(SKVStore *pStore, uint64_t uid, void *cont, int contLen);
+int       tdDropKVStoreRecord(SKVStore *pStore, uint64_t uid);
 int       tdKVStoreEndCommit(SKVStore *pStore);
 
 #ifdef __cplusplus
diff --git a/src/util/src/tkvstore.c b/src/util/src/tkvstore.c
index 148d8235a6fb832183e30a346cd4b6898b60f1cb..88cd446349a351da7855d7fcdfcd2291c830381f 100644
--- a/src/util/src/tkvstore.c
+++ b/src/util/src/tkvstore.c
@@ -34,42 +34,67 @@
 #define TD_KVSTORE_SNAP_SUFFIX ".snap"
 #define TD_KVSTORE_NEW_SUFFIX ".new"
 
+typedef struct {
+  uint64_t uid;
+  int64_t  offset;
+  int64_t  size;
+} SKVRecord;
+
 static int       tdInitKVStoreHeader(int fd, char *fname);
 static void *    tdEncodeStoreInfo(void *buf, SStoreInfo *pInfo);
-// static void *    tdDecodeStoreInfo(void *buf, SStoreInfo *pInfo);
+static void *    tdDecodeStoreInfo(void *buf, SStoreInfo *pInfo);
 static SKVStore *tdNewKVStore(char *fname, iterFunc iFunc, afterFunc aFunc, void *appH);
 static char *    tdGetKVStoreSnapshotFname(char *fdata);
 static char *    tdGetKVStoreNewFname(char *fdata);
 static void      tdFreeKVStore(SKVStore *pStore);
 static int       tdUpdateKVStoreHeader(int fd, char *fname, SStoreInfo *pInfo);
+static int       tdLoadKVStoreHeader(int fd, char *fname, SStoreInfo *pInfo);
+static void *    tdEncodeKVRecord(void *buf, SKVRecord *pRecord);
+static void *    tdDecodeKVRecord(void *buf, SKVRecord *pRecord);
+static int       tdRestoreKVStore(SKVStore *pStore);
 
 int tdCreateKVStore(char *fname) {
-  char *tname = strdup(fname);
-  if (tname == NULL) return TSDB_CODE_COM_OUT_OF_MEMORY;
-
   int fd = open(fname, O_RDWR | O_CREAT, 0755);
   if (fd < 0) {
     uError("failed to open file %s since %s", fname, strerror(errno));
-    return TAOS_SYSTEM_ERROR(errno);
+    terrno = TAOS_SYSTEM_ERROR(errno);
+    return -1;
   }
 
-  int code = tdInitKVStoreHeader(fd, fname);
-  if (code != TSDB_CODE_SUCCESS) return code;
+  if (tdInitKVStoreHeader(fd, fname) < 0) {
+    close(fd);
+    return -1;
+  }
 
   if (fsync(fd) < 0) {
     uError("failed to fsync file %s since %s", fname, strerror(errno));
-    return TAOS_SYSTEM_ERROR(errno);
+    terrno = TAOS_SYSTEM_ERROR(errno);
+    close(fd);
+    return -1;
   }
 
   if (close(fd) < 0) {
     uError("failed to close file %s since %s", fname, strerror(errno));
-    return TAOS_SYSTEM_ERROR(errno);
+    terrno = TAOS_SYSTEM_ERROR(errno);
+    return -1;
   }
 
-  return TSDB_CODE_SUCCESS;
+  return 0;
+}
+
+int tdDestroyKVStore(char *fname) {
+  if (remove(fname) < 0) {
+    uError("failed to remove file %s since %s", fname, strerror(errno));
+    terrno = TAOS_SYSTEM_ERROR(errno);
+    return -1;
+  }
+
+  return 0;
 }
 
 SKVStore *tdOpenKVStore(char *fname, iterFunc iFunc, afterFunc aFunc, void *appH) {
+  SStoreInfo info = {0};
+
   SKVStore *pStore = tdNewKVStore(fname, iFunc, aFunc, appH);
   if (pStore == NULL) return NULL;
 
@@ -89,14 +114,44 @@ SKVStore *tdOpenKVStore(char *fname, iterFunc iFunc, afterFunc aFunc, void *appH
       goto _err;
     }
 
-    // TODO: rewind the file
+    if (tdLoadKVStoreHeader(pStore->sfd, pStore->fsnap, &info) < 0) goto _err;
+
+    if (ftruncate(pStore->fd, info.size) < 0) {
+      uError("failed to truncate %s to " PRId64 " size since %s", pStore->fname, info.size, strerror(errno));
+      terrno = TAOS_SYSTEM_ERROR(errno);
+      goto _err;
+    }
+
+    if (tdUpdateKVStoreHeader(pStore->fd, pStore->fname, &info) < 0) goto _err;
 
     close(pStore->sfd);
     pStore->sfd = -1;
     remove(pStore->fsnap);
   }
 
-  // TODO: Recover from the file
+  if (tdLoadKVStoreHeader(pStore->fd, pStore->fname, &info) < 0) goto _err;
+
+  struct stat tfstat;
+  if (fstat(pStore->fd, &tfstat) < 0) {
+    uError("failed to fstat file %s since %s", pStore->fname, strerror(errno));
+    terrno = TAOS_SYSTEM_ERROR(errno);
+    goto _err;
+  }
+
+  ASSERT(info.size == tfstat.st_size);
+
+  if (lseek(pStore->fd, TD_KVSTORE_HEADER_SIZE, SEEK_SET) < 0) {
+    uError("failed to lseek file %s since %s", pStore->fname, strerror(errno));
+    terrno = TAOS_SYSTEM_ERROR(errno);
+    goto _err;
+  }
+
+  pStore->info.size += TD_KVSTORE_HEADER_SIZE;
+
+  if (tdRestoreKVStore(pStore) < 0) goto _err;
+
+  close(pStore->fd);
+  pStore->fd = -1;
 
   return pStore;
 
@@ -113,7 +168,11 @@ _err:
   return NULL;
 }
 
+void tdCloseKVStore(SKVStore *pStore) { tdFreeKVStore(pStore); }
+
 int tdKVStoreStartCommit(SKVStore *pStore) {
+  ASSERT(pStore->fd < 0);
+
   pStore->fd = open(pStore->fname, O_RDWR);
   if (pStore->fd < 0) {
     uError("failed to open file %s since %s", pStore->fname, strerror(errno));
@@ -147,6 +206,14 @@ int tdKVStoreStartCommit(SKVStore *pStore) {
   }
   pStore->sfd = -1;
 
+  if (lseek(pStore->fd, 0, SEEK_END) < 0) {
+    uError("failed to lseek file %s since %s", pStore->fname, strerror(errno));
+    terrno = TAOS_SYSTEM_ERROR(errno);
+    goto _err;
+  }
+
+  ASSERT(pStore->info.size == lseek(pStore->fd, 0, SEEK_CUR));
+
   return 0;
 
 _err:
@@ -162,11 +229,50 @@ _err:
   return -1;
 }
 
+int tdUpdateKVStoreRecord(SKVStore *pStore, uint64_t uid, void *cont, int contLen) {
+  SKVRecord *pRecord = taosHashGet(pStore->map, (void *)&uid, sizeof(uid));
+  if (pRecord != NULL) {
+    pStore->info.tombSize += (pRecord->size + sizeof(SKVRecord));
+  }
+
+  // TODO
+  return 0;
+}
+
+int tdDropKVStoreRecord(SKVStore *pStore, uint64_t uid) {
+  SKVRecord rInfo = {0};
+  char      buf[128] = "\0";
+
+  SKVRecord *pRecord = taosHashGet(pStore->map, &uid, sizeof(uid));
+  if (pRecord == NULL) {
+    uError("failed to drop KV store record with key " PRIu64 " since not find", uid);
+    return -1;
+  }
+
+  rInfo.offset = -pRecord->offset;
+  rInfo.uid = pRecord->uid;
+  rInfo.size = pRecord->size;
+
+  void *pBuf = tdEncodeKVRecord(buf, &rInfo);
+
+  if (twrite(pStore->fd, buf, POINTER_DISTANCE(pBuf, buf)) < POINTER_DISTANCE(pBuf, buf)) {
+    uError("failed to write %d bytes to file %s since %s", POINTER_DISTANCE(pBuf, buf), pStore->fname, strerror(errno));
+    terrno = TAOS_SYSTEM_ERROR(errno);
+    return -1;
+  }
+
+  pStore->info.size += POINTER_DISTANCE(pBuf, buf);
+  pStore->info.nDels++;
+  pStore->info.nRecords--;
+  pStore->info.tombSize += (rInfo.size + sizeof(SKVRecord) * 2);
+
+  return 0;
+}
+
 int tdKVStoreEndCommit(SKVStore *pStore) {
   ASSERT(pStore->fd > 0);
 
-  terrno = tdUpdateKVStoreHeader(pStore->fd, pStore->fname, &(pStore->info));
-  if (terrno != TSDB_CODE_SUCCESS) return -1;
+  if (tdUpdateKVStoreHeader(pStore->fd, pStore->fname, &(pStore->info)) < 0) return -1;
 
   if (fsync(pStore->fd) < 0) {
     uError("failed to fsync file %s since %s", pStore->fname, strerror(errno));
@@ -179,27 +285,56 @@ int tdKVStoreEndCommit(SKVStore *pStore) {
     terrno = TAOS_SYSTEM_ERROR(errno);
     return -1;
   }
+  pStore->fd = -1;
 
   remove(pStore->fsnap);
   return 0;
 }
 
+static int tdLoadKVStoreHeader(int fd, char *fname, SStoreInfo *pInfo) {
+  char buf[TD_KVSTORE_HEADER_SIZE] = "\0";
+
+  if (lseek(fd, 0, SEEK_SET) < 0) {
+    uError("failed to lseek file %s since %s", fname, strerror(errno));
+    terrno = TAOS_SYSTEM_ERROR(errno);
+    return -1;
+  }
+
+  if (tread(fd, buf, TD_KVSTORE_HEADER_SIZE) < TD_KVSTORE_HEADER_SIZE) {
+    uError("failed to read %d bytes from file %s since %s", TD_KVSTORE_HEADER_SIZE, fname, strerror(errno));
+    terrno = TAOS_SYSTEM_ERROR(errno);
+    return -1;
+  }
+
+  if (!taosCheckChecksumWhole((uint8_t *)buf, TD_KVSTORE_HEADER_SIZE)) {
+    uError("file %s is broken", fname);
+    terrno = TSDB_CODE_COM_FILE_CORRUPTED;
+    return -1;
+  }
+
+  tdDecodeStoreInfo(buf, pInfo);
+
+  return 0;
+}
+
 static int tdUpdateKVStoreHeader(int fd, char *fname, SStoreInfo *pInfo) {
   char buf[TD_KVSTORE_HEADER_SIZE] = "\0";
 
   if (lseek(fd, 0, SEEK_SET) < 0) {
     uError("failed to lseek file %s since %s", fname, strerror(errno));
-    return TAOS_SYSTEM_ERROR(errno);
+    terrno = TAOS_SYSTEM_ERROR(errno);
+    return -1;
   }
 
   tdEncodeStoreInfo(buf, pInfo);
   taosCalcChecksumAppend(0, (uint8_t *)buf, TD_KVSTORE_HEADER_SIZE);
   if (twrite(fd, buf, TD_KVSTORE_HEADER_SIZE) < TD_KVSTORE_HEADER_SIZE) {
-    uError("failed to write file %s %d bytes since %s", fname, TD_KVSTORE_HEADER_SIZE, strerror(errno));
-    return TAOS_SYSTEM_ERROR(errno);
+    uError("failed to write %d bytes to file %s since %s", TD_KVSTORE_HEADER_SIZE, fname, strerror(errno));
+    terrno = TAOS_SYSTEM_ERROR(errno);
+    return -1;
   }
 
-  return TSDB_CODE_SUCCESS;
+  return 0;
 }
 
 static int tdInitKVStoreHeader(int fd, char *fname) {
@@ -217,21 +352,24 @@ static void *tdEncodeStoreInfo(void *buf, SStoreInfo *pInfo) {
   return buf;
 }
 
-// static void *tdDecodeStoreInfo(void *buf, SStoreInfo *pInfo) {
-//   buf = taosDecodeVariantI64(buf, &(pInfo->size));
-//   buf = taosDecodeVariantI64(buf, &(pInfo->tombSize));
-//   buf = taosDecodeVariantI64(buf, &(pInfo->nRecords));
-//   buf = taosDecodeVariantI64(buf, &(pInfo->nDels));
+static void *tdDecodeStoreInfo(void *buf, SStoreInfo *pInfo) {
+  buf = taosDecodeVariantI64(buf, &(pInfo->size));
+  buf = taosDecodeVariantI64(buf, &(pInfo->tombSize));
+  buf = taosDecodeVariantI64(buf, &(pInfo->nRecords));
+  buf = taosDecodeVariantI64(buf, &(pInfo->nDels));
 
-//   return buf;
-// }
+  return buf;
+}
 
 static SKVStore *tdNewKVStore(char *fname, iterFunc iFunc, afterFunc aFunc, void *appH) {
   SKVStore *pStore = (SKVStore *)malloc(sizeof(SKVStore));
   if (pStore == NULL) goto _err;
 
   pStore->fname = strdup(fname);
-  if (pStore->map == NULL) goto _err;
+  if (pStore->map == NULL) {
+    terrno = TSDB_CODE_COM_OUT_OF_MEMORY;
+    goto _err;
+  }
 
   pStore->fsnap = tdGetKVStoreSnapshotFname(fname);
   if (pStore->fsnap == NULL) goto _err;
@@ -254,7 +392,6 @@ static SKVStore *tdNewKVStore(char *fname, iterFunc iFunc, afterFunc aFunc, void
   return pStore;
 
 _err:
-  terrno = TSDB_CODE_COM_OUT_OF_MEMORY;
   tdFreeKVStore(pStore);
   return NULL;
 }
@@ -289,4 +426,116 @@ static char *tdGetKVStoreNewFname(char *fdata) {
   }
   sprintf(fname, "%s%s", fdata, TD_KVSTORE_NEW_SUFFIX);
   return fname;
+}
+
+static void *tdEncodeKVRecord(void *buf, SKVRecord *pRecord) {
+  buf = taosEncodeFixedU64(buf, pRecord->uid);
+  buf = taosEncodeFixedI64(buf, pRecord->offset);
+  buf = taosEncodeFixedI64(buf, pRecord->size);
+
+  return buf;
+}
+
+static void *tdDecodeKVRecord(void *buf, SKVRecord *pRecord) {
+  buf = taosDecodeFixedU64(buf, &(pRecord->uid));
+  buf = taosDecodeFixedI64(buf, &(pRecord->offset));
+  buf = taosDecodeFixedI64(buf, &(pRecord->size));
+
+  return buf;
+}
+
+static int tdRestoreKVStore(SKVStore *pStore) {
+  char      tbuf[128] = "\0";
+  void *    buf = NULL;
+  int       maxBufSize = 0;
+  SKVRecord rInfo = {0};
+
+  ASSERT(TD_KVSTORE_HEADER_SIZE == lseek(pStore->fd, 0, SEEK_CUR));
+
+  while (true) {
+    ssize_t tsize = tread(pStore->fd, tbuf, sizeof(SKVRecord));
+    if (tsize == 0) break;
+    if (tsize < sizeof(SKVRecord)) {
+      uError("failed to read %d bytes from file %s since %s", sizeof(SKVRecord), pStore->fname, strerror(errno));
+      terrno = TAOS_SYSTEM_ERROR(errno);
+      goto _err;
+    }
+
+    char *pBuf = tdDecodeKVRecord(tbuf, &rInfo);
+    ASSERT(POINTER_DISTANCE(pBuf, tbuf) == sizeof(SKVRecord));
+    ASSERT(rInfo.offset > 0 ? pStore->info.size == rInfo.offset : true);
+
+    if (rInfo.offset < 0) {
+      taosHashRemove(pStore->map, (void *)(&rInfo.uid), sizeof(rInfo.uid));
+      pStore->info.size += sizeof(SKVRecord);
+      pStore->info.nRecords--;
+      pStore->info.nDels++;
+      pStore->info.tombSize += (rInfo.size + sizeof(SKVRecord) + sizeof(SKVRecord));
+    } else {
+      // TODO: add statistics
+      ASSERT(rInfo.offset > 0 && rInfo.size > 0);
+      if (taosHashPut(pStore->map, (void *)(&rInfo.uid), sizeof(rInfo.uid), &rInfo, sizeof(rInfo)) < 0) {
+        uError("failed to put record in KV store %s", pStore->fname);
+        terrno = TSDB_CODE_COM_OUT_OF_MEMORY;
+        goto _err;
+      }
+
+      maxBufSize = MAX(maxBufSize, rInfo.size);
+
+      if (lseek(pStore->fd, rInfo.size, SEEK_CUR) < 0) {
+        uError("failed to lseek file %s since %s", pStore->fname, strerror(errno));
+        terrno = TAOS_SYSTEM_ERROR(errno);
+        goto _err;
+      }
+    }
+  }
+
+  buf = malloc(maxBufSize);
+  if (buf == NULL) {
+    uError("failed to allocate %d bytes in KV store %s", maxBufSize, pStore->fname);
+    terrno = TAOS_SYSTEM_ERROR(errno);
+    goto _err;
+  }
+
+  SHashMutableIterator *pIter = taosHashCreateIter(pStore->map);
+  if (pIter == NULL) {
+    uError("failed to create hash iter while opening KV store %s", pStore->fname);
+    terrno = TSDB_CODE_COM_OUT_OF_MEMORY;
+    goto _err;
+  }
+
+  while (taosHashIterNext(pIter)) {
+    SKVRecord *pRecord = taosHashIterGet(pIter);
+
+    if (lseek(pStore->fd, pRecord->offset, SEEK_SET) < 0) {
+      uError("failed to lseek file %s since %s", pStore->fname, strerror(errno));
+      terrno = TAOS_SYSTEM_ERROR(errno);
+      goto _err;
+    }
+
+    if (tread(pStore->fd, buf, pRecord->size) < pRecord->size) {
+      uError("failed to read %d bytes from file %s since %s", pRecord->size, pStore->fname, strerror(errno));
+      terrno = TAOS_SYSTEM_ERROR(errno);
+      goto _err;
+    }
+
+    if (!taosCheckChecksumWhole((uint8_t *)buf, pRecord->size)) {
+      uError("file %s has checksum error, offset " PRId64 " size %d", pStore->fname, pRecord->offset, pRecord->size);
+      terrno = TSDB_CODE_COM_FILE_CORRUPTED;
+      goto _err;
+    }
+
+    if (pStore->iFunc) (*pStore->iFunc)(pStore->appH, buf, pRecord->size);
+  }
+
+  taosHashDestroyIter(pIter);
+
+  if (pStore->aFunc) (*pStore->aFunc)(pStore->appH);
+
+  tfree(buf);
+  return 0;
+
+_err:
+  tfree(buf);
+  return -1;
 }
\ No newline at end of file