diff --git a/include/dnode/vnode/tq/tq.h b/include/dnode/vnode/tq/tq.h
index 85533f65bc25154ead1c8771f7f06c31fad0e3ce..7359df92cc680c7c052131e843ed158dcf4ff8f4 100644
--- a/include/dnode/vnode/tq/tq.h
+++ b/include/dnode/vnode/tq/tq.h
@@ -256,7 +256,7 @@ typedef struct STQ {
   // the collection of group handle
   // the handle of kvstore
   char*  path;
-  STqCfg*    tqConfig;
+  STqCfg*      tqConfig;
   TqLogReader* tqLogReader; 
   TqMemRef     tqMemRef;
   TqMetaStore* tqMeta;
diff --git a/include/libs/wal/wal.h b/include/libs/wal/wal.h
index 48c775292a1e9f9fa3c5b828169389351df99a4a..ae1e630c6fff6caa46e897dec51207fe4ce3386c 100644
--- a/include/libs/wal/wal.h
+++ b/include/libs/wal/wal.h
@@ -44,7 +44,7 @@ typedef struct SWalReadHead {
   int8_t   reserved[2];
   int32_t  len;
   int64_t  version;
-  char     cont[];
+  char     body[];
 } SWalReadHead;
 
 typedef struct {
@@ -52,9 +52,9 @@ typedef struct {
   int32_t  fsyncPeriod;      // millisecond
   int32_t  retentionPeriod;  // secs
   int32_t  rollPeriod;       // secs
-  int32_t  retentionSize;       // secs
+  int64_t  retentionSize;
   int64_t  segSize;
-  EWalType walLevel;         // wal level
+  EWalType level;         // wal level
 } SWalCfg;
 
 typedef struct {
@@ -90,15 +90,17 @@ typedef struct {
 #define WAL_CUR_FILE_WRITABLE 2
 #define WAL_CUR_FAILED        4
 
+typedef struct SWalVer {
+  int64_t firstVer;
+  int64_t verInSnapshotting;
+  int64_t snapshotVer;
+  int64_t commitVer;
+  int64_t lastVer;
+} SWalVer;
+
 typedef struct SWal {
   // cfg
-  int32_t  vgId;
-  int32_t  fsyncPeriod;  // millisecond
-  int32_t  rollPeriod;  // second
-  int64_t  segSize;
-  int64_t  retentionSize;
-  int32_t  retentionPeriod;
-  EWalType level;
+  SWalCfg cfg;
   //total size
   int64_t  totSize;
   //fsync seq
@@ -109,12 +111,7 @@ typedef struct SWal {
   int64_t writeLogTfd;
   int64_t writeIdxTfd;
   //wal lifecycle
-  int64_t firstVersion;
-  int64_t snapshotVersion;
-  int64_t commitVersion;
-  int64_t lastVersion;
-  //snapshotting version
-  int64_t snapshottingVer;
+  SWalVer vers;
   //roll status
   int64_t lastRollSeq;
   //file set
@@ -126,9 +123,20 @@ typedef struct SWal {
   //path
   char path[WAL_PATH_LEN];
   //reusable write head
-  SWalHead head;
+  SWalHead writeHead;
 } SWal;  // WAL HANDLE
 
+typedef struct SWalReadHandle {
+  SWal*        pWal;
+  int64_t      readLogTfd;
+  int64_t      readIdxTfd;
+  int64_t      curFileFirstVer;
+  int64_t      curVersion;
+  int64_t      capacity;
+  int64_t      status;  //if cursor valid
+  SWalHead     head;
+} SWalReadHandle;
+
 typedef int32_t (*FWalWrite)(void *ahandle, void *pHead);
 
 // module initialization
@@ -154,6 +162,10 @@ int32_t walEndTakeSnapshot(SWal *);
 //int32_t  walDataCorrupted(SWal*);
 
 // read
+SWalReadHandle* walOpenReadHandle(SWal *);
+void    walCloseReadHandle(SWalReadHandle *);
+int32_t walReadWithHandle(SWalReadHandle *pRead, int64_t ver);
+
 int32_t walRead(SWal *, SWalHead **, int64_t ver);
 int32_t walReadWithFp(SWal *, FWalWrite writeFp, int64_t verStart, int32_t readNum);
 
diff --git a/source/libs/wal/inc/walInt.h b/source/libs/wal/inc/walInt.h
index f8f2e2eadd35fb67cb555c4e60e6eecdc6cefce9..ec01f7d7fc91e7689dffbf53d266f7e4f652ee29 100644
--- a/source/libs/wal/inc/walInt.h
+++ b/source/libs/wal/inc/walInt.h
@@ -90,7 +90,7 @@ static inline int walValidHeadCksum(SWalHead* pHead) {
 }
 
 static inline int walValidBodyCksum(SWalHead* pHead) {
-  return taosCheckChecksum((uint8_t*)pHead->head.cont, pHead->head.len, pHead->cksumBody);
+  return taosCheckChecksum((uint8_t*)pHead->head.body, pHead->head.len, pHead->cksumBody);
 }
 
 static inline int walValidCksum(SWalHead *pHead, void* body, int64_t bodyLen) {
diff --git a/source/libs/wal/src/walMeta.c b/source/libs/wal/src/walMeta.c
index 705cf051be8055b902ed6c3899491b7c99d55212..49f4fde3a0331ea19b10599b1fd52a2429d979ac 100644
--- a/source/libs/wal/src/walMeta.c
+++ b/source/libs/wal/src/walMeta.c
@@ -25,15 +25,15 @@
 #include <regex.h>
 
 int64_t walGetFirstVer(SWal *pWal) {
-  return pWal->firstVersion;
+  return pWal->vers.firstVer;
 }
 
 int64_t walGetSnaphostVer(SWal *pWal) {
-  return pWal->snapshotVersion;
+  return pWal->vers.snapshotVer;
 }
 
 int64_t walGetLastVer(SWal *pWal) {
-  return pWal->lastVersion;
+  return pWal->vers.lastVer;
 }
 
 int walRollFileInfo(SWal* pWal) {
@@ -42,7 +42,7 @@ int walRollFileInfo(SWal* pWal) {
   SArray* pArray = pWal->fileInfoSet;
   if(taosArrayGetSize(pArray) != 0) {
     WalFileInfo *pInfo = taosArrayGetLast(pArray);
-    pInfo->lastVer = pWal->lastVersion;
+    pInfo->lastVer = pWal->vers.lastVer;
     pInfo->closeTs = ts;
   }
 
@@ -51,7 +51,7 @@ int walRollFileInfo(SWal* pWal) {
   if(pNewInfo == NULL) {
     return -1;
   }
-  pNewInfo->firstVer = pWal->lastVersion + 1;
+  pNewInfo->firstVer = pWal->vers.lastVer + 1;
   pNewInfo->lastVer = -1;
   pNewInfo->createTs = ts;
   pNewInfo->closeTs = -1;
@@ -74,13 +74,13 @@ char* walMetaSerialize(SWal* pWal) {
     return NULL;
   }
   cJSON_AddItemToObject(pRoot, "meta", pMeta);
-  sprintf(buf, "%" PRId64, pWal->firstVersion);
+  sprintf(buf, "%" PRId64, pWal->vers.firstVer);
   cJSON_AddStringToObject(pMeta, "firstVer", buf);
-  sprintf(buf, "%" PRId64, pWal->snapshotVersion);
+  sprintf(buf, "%" PRId64, pWal->vers.snapshotVer);
   cJSON_AddStringToObject(pMeta, "snapshotVer", buf);
-  sprintf(buf, "%" PRId64, pWal->commitVersion);
+  sprintf(buf, "%" PRId64, pWal->vers.commitVer);
   cJSON_AddStringToObject(pMeta, "commitVer", buf);
-  sprintf(buf, "%" PRId64, pWal->lastVersion);
+  sprintf(buf, "%" PRId64, pWal->vers.lastVer);
   cJSON_AddStringToObject(pMeta, "lastVer", buf);
 
   cJSON_AddItemToObject(pRoot, "files", pFiles);
@@ -116,13 +116,13 @@ int walMetaDeserialize(SWal* pWal, const char* bytes) {
   pRoot = cJSON_Parse(bytes);
   pMeta = cJSON_GetObjectItem(pRoot, "meta");
   pField = cJSON_GetObjectItem(pMeta, "firstVer");
-  pWal->firstVersion = atoll(cJSON_GetStringValue(pField));
+  pWal->vers.firstVer = atoll(cJSON_GetStringValue(pField));
   pField = cJSON_GetObjectItem(pMeta, "snapshotVer");
-  pWal->snapshotVersion = atoll(cJSON_GetStringValue(pField));
+  pWal->vers.snapshotVer = atoll(cJSON_GetStringValue(pField));
   pField = cJSON_GetObjectItem(pMeta, "commitVer");
-  pWal->commitVersion = atoll(cJSON_GetStringValue(pField));
+  pWal->vers.commitVer = atoll(cJSON_GetStringValue(pField));
   pField = cJSON_GetObjectItem(pMeta, "lastVer");
-  pWal->lastVersion = atoll(cJSON_GetStringValue(pField));
+  pWal->vers.lastVer = atoll(cJSON_GetStringValue(pField));
 
   pFiles = cJSON_GetObjectItem(pRoot, "files");
   int sz = cJSON_GetArraySize(pFiles);
@@ -161,7 +161,7 @@ static int walFindCurMetaVer(SWal* pWal) {
 
   DIR *dir = opendir(pWal->path); 
   if(dir == NULL) {
-    wError("vgId:%d, path:%s, failed to open since %s", pWal->vgId, pWal->path, strerror(errno));
+    wError("vgId:%d, path:%s, failed to open since %s", pWal->cfg.vgId, pWal->path, strerror(errno));
     return -1;
   }
 
diff --git a/source/libs/wal/src/walMgmt.c b/source/libs/wal/src/walMgmt.c
index a47f27f1425efbb9b7f52ecab69852839534caa5..31f2ef037aed0b2bb90248b932ba687a2f7c4bd3 100644
--- a/source/libs/wal/src/walMgmt.c
+++ b/source/libs/wal/src/walMgmt.c
@@ -86,21 +86,15 @@ SWal *walOpen(const char *path, SWalCfg *pCfg) {
   pWal->writeCur = -1;
 
   //set config
-  pWal->vgId = pCfg->vgId;
-  pWal->fsyncPeriod = pCfg->fsyncPeriod;
-  pWal->rollPeriod = pCfg->rollPeriod;
-  pWal->segSize = pCfg->segSize;
-  pWal->retentionSize = pCfg->retentionSize;
-  pWal->retentionPeriod = pCfg->retentionPeriod;
-  pWal->level = pCfg->walLevel;
+  memcpy(&pWal->cfg, pCfg, sizeof(SWalCfg));
 
   //init version info
-  pWal->firstVersion = -1;
-  pWal->commitVersion = -1;
-  pWal->snapshotVersion = -1;
-  pWal->lastVersion = -1;
+  pWal->vers.firstVer = -1;
+  pWal->vers.commitVer = -1;
+  pWal->vers.snapshotVer = -1;
+  pWal->vers.lastVer = -1;
 
-  pWal->snapshottingVer = -1;
+  pWal->vers.verInSnapshotting = -1;
 
   pWal->totSize = 0;
 
@@ -108,8 +102,8 @@ SWal *walOpen(const char *path, SWalCfg *pCfg) {
   pWal->lastRollSeq = -1;
 
   //init write buffer
-  memset(&pWal->head, 0, sizeof(SWalHead));
-  pWal->head.head.sver = 0;
+  memset(&pWal->writeHead, 0, sizeof(SWalHead));
+  pWal->writeHead.head.sver = 0;
 
   tstrncpy(pWal->path, path, sizeof(pWal->path));
   pthread_mutex_init(&pWal->mutex, NULL);
@@ -129,7 +123,7 @@ SWal *walOpen(const char *path, SWalCfg *pCfg) {
   }
   walReadMeta(pWal);
 
-  wDebug("vgId:%d, wal:%p is opened, level:%d fsyncPeriod:%d", pWal->vgId, pWal, pWal->level, pWal->fsyncPeriod);
+  wDebug("vgId:%d, wal:%p is opened, level:%d fsyncPeriod:%d", pWal->cfg.vgId, pWal, pWal->cfg.level, pWal->cfg.fsyncPeriod);
 
   return pWal;
 }
@@ -137,17 +131,17 @@ SWal *walOpen(const char *path, SWalCfg *pCfg) {
 int32_t walAlter(SWal *pWal, SWalCfg *pCfg) {
   if (pWal == NULL) return TSDB_CODE_WAL_APP_ERROR;
 
-  if (pWal->level == pCfg->walLevel && pWal->fsyncPeriod == pCfg->fsyncPeriod) {
-    wDebug("vgId:%d, old walLevel:%d fsync:%d, new walLevel:%d fsync:%d not change", pWal->vgId, pWal->level,
-           pWal->fsyncPeriod, pCfg->walLevel, pCfg->fsyncPeriod);
+  if (pWal->cfg.level == pCfg->level && pWal->cfg.fsyncPeriod == pCfg->fsyncPeriod) {
+    wDebug("vgId:%d, old walLevel:%d fsync:%d, new walLevel:%d fsync:%d not change", pWal->cfg.vgId, pWal->cfg.level,
+           pWal->cfg.fsyncPeriod, pCfg->level, pCfg->fsyncPeriod);
     return 0;
   }
 
-  wInfo("vgId:%d, change old walLevel:%d fsync:%d, new walLevel:%d fsync:%d", pWal->vgId, pWal->level,
-        pWal->fsyncPeriod, pCfg->walLevel, pCfg->fsyncPeriod);
+  wInfo("vgId:%d, change old walLevel:%d fsync:%d, new walLevel:%d fsync:%d", pWal->cfg.vgId, pWal->cfg.level,
+        pWal->cfg.fsyncPeriod, pCfg->level, pCfg->fsyncPeriod);
 
-  pWal->level = pCfg->walLevel;
-  pWal->fsyncPeriod = pCfg->fsyncPeriod;
+  pWal->cfg.level = pCfg->level;
+  pWal->cfg.fsyncPeriod = pCfg->fsyncPeriod;
   pWal->fsyncSeq = pCfg->fsyncPeriod / 1000;
   if (pWal->fsyncSeq <= 0) pWal->fsyncSeq = 1;
 
@@ -171,22 +165,22 @@ void walClose(SWal *pWal) {
 
 static int32_t walInitObj(SWal *pWal) {
   if (taosMkDir(pWal->path) != 0) {
-    wError("vgId:%d, path:%s, failed to create directory since %s", pWal->vgId, pWal->path, strerror(errno));
+    wError("vgId:%d, path:%s, failed to create directory since %s", pWal->cfg.vgId, pWal->path, strerror(errno));
     return TAOS_SYSTEM_ERROR(errno);
   }
   pWal->fileInfoSet = taosArrayInit(8, sizeof(WalFileInfo));
   if(pWal->fileInfoSet == NULL) {
-    wError("vgId:%d, path:%s, failed to init taosArray %s", pWal->vgId, pWal->path, strerror(errno));
+    wError("vgId:%d, path:%s, failed to init taosArray %s", pWal->cfg.vgId, pWal->path, strerror(errno));
     return TAOS_SYSTEM_ERROR(errno);
   }
 
-  wDebug("vgId:%d, object is initialized", pWal->vgId);
+  wDebug("vgId:%d, object is initialized", pWal->cfg.vgId);
   return 0;
 }
 
 static void walFreeObj(void *wal) {
   SWal *pWal = wal;
-  wDebug("vgId:%d, wal:%p is freed", pWal->vgId, pWal);
+  wDebug("vgId:%d, wal:%p is freed", pWal->cfg.vgId, pWal);
 
   tfClose(pWal->writeLogTfd);
   tfClose(pWal->writeIdxTfd);
@@ -197,7 +191,7 @@ static void walFreeObj(void *wal) {
 }
 
 static bool walNeedFsync(SWal *pWal) {
-  if (pWal->fsyncPeriod <= 0 || pWal->level != TAOS_WAL_FSYNC) {
+  if (pWal->cfg.fsyncPeriod <= 0 || pWal->cfg.level != TAOS_WAL_FSYNC) {
     return false;
   }
 
@@ -217,10 +211,10 @@ static void walFsyncAll() {
   SWal *pWal = taosIterateRef(tsWal.refSetId, 0);
   while (pWal) {
     if (walNeedFsync(pWal)) {
-      wTrace("vgId:%d, do fsync, level:%d seq:%d rseq:%d", pWal->vgId, pWal->level, pWal->fsyncSeq, atomic_load_32(&tsWal.seq));
+      wTrace("vgId:%d, do fsync, level:%d seq:%d rseq:%d", pWal->cfg.vgId, pWal->cfg.level, pWal->fsyncSeq, atomic_load_32(&tsWal.seq));
       int32_t code = tfFsync(pWal->writeLogTfd);
       if (code != 0) {
-        wError("vgId:%d, file:%"PRId64".log, failed to fsync since %s", pWal->vgId, walGetLastFileFirstVer(pWal), strerror(code));
+        wError("vgId:%d, file:%"PRId64".log, failed to fsync since %s", pWal->cfg.vgId, walGetLastFileFirstVer(pWal), strerror(code));
       }
     }
     pWal = taosIterateRef(tsWal.refSetId, pWal->refId);
diff --git a/source/libs/wal/src/walRead.c b/source/libs/wal/src/walRead.c
index 27dffddf83e129888264a8347a108898308aa40a..554a5c846b5df84e76d192bb588a51e7e2020ca5 100644
--- a/source/libs/wal/src/walRead.c
+++ b/source/libs/wal/src/walRead.c
@@ -16,6 +16,147 @@
 #include "walInt.h"
 #include "tfile.h"
 
+SWalReadHandle* walOpenReadHandle(SWal* pWal) {
+  SWalReadHandle *pRead = malloc(sizeof(SWalReadHandle));
+  if(pRead == NULL) {
+    return NULL;
+  }
+  memset(pRead, 0, sizeof(SWalReadHandle));
+  pRead->pWal = pWal;
+  pRead->readIdxTfd = -1;
+  pRead->readLogTfd = -1;
+  return NULL;
+}
+
+void walCloseReadHandle(SWalReadHandle *pRead) {
+  tfClose(pRead->readIdxTfd);
+  tfClose(pRead->readLogTfd);
+  free(pRead);
+}
+
+int32_t walRegisterRead(SWalReadHandle *pRead, int64_t ver) {
+  return 0;
+}
+
+static int32_t walReadSeekFilePos(SWalReadHandle *pRead, int64_t fileFirstVer, int64_t ver) {
+  int code = 0;
+
+  int64_t idxTfd = pRead->readIdxTfd;
+  int64_t logTfd = pRead->readLogTfd;
+  
+  //seek position
+  int64_t offset = (ver - fileFirstVer) * WAL_IDX_ENTRY_SIZE;
+  code = tfLseek(idxTfd, offset, SEEK_SET);
+  if(code != 0) {
+    return -1;
+  }
+  WalIdxEntry entry;
+  code = tfRead(idxTfd, &entry, sizeof(WalIdxEntry));
+  if(code != 0) {
+    return -1;
+  }
+  //TODO:deserialize
+  ASSERT(entry.ver == ver);
+  code = tfLseek(logTfd, entry.offset, SEEK_SET);
+  if (code != 0) {
+    return -1;
+  }
+  return code;
+}
+
+static int32_t walReadChangeFile(SWalReadHandle *pRead, int64_t fileFirstVer) {
+  char fnameStr[WAL_FILE_LEN];
+
+  tfClose(pRead->readIdxTfd);
+  tfClose(pRead->readLogTfd);
+
+  walBuildLogName(pRead->pWal, fileFirstVer, fnameStr);
+  int logTfd = tfOpenRead(fnameStr);
+  if(logTfd < 0) {
+    return -1;
+  }
+
+  walBuildIdxName(pRead->pWal, fileFirstVer, fnameStr);
+  int idxTfd = tfOpenRead(fnameStr);
+  if(idxTfd < 0) {
+    return -1;
+  }
+
+  pRead->readLogTfd = logTfd;
+  pRead->readIdxTfd = idxTfd;
+  return 0;
+}
+
+static int32_t walReadSeekVer(SWalReadHandle *pRead, int64_t ver) {
+  int code;
+  SWal *pWal = pRead->pWal;
+  if(ver == pWal->vers.lastVer) {
+    return 0;
+  }
+  if(ver > pWal->vers.lastVer || ver < pWal->vers.firstVer) {
+    return -1;
+  }
+  if(ver < pWal->vers.snapshotVer) {
+
+  }
+
+  WalFileInfo tmpInfo;
+  tmpInfo.firstVer = ver;
+  //bsearch in fileSet
+  WalFileInfo* pRet = taosArraySearch(pWal->fileInfoSet, &tmpInfo, compareWalFileInfo, TD_LE);
+  ASSERT(pRet != NULL);
+  if(pRead->curFileFirstVer != pRet->firstVer) {
+    code = walReadChangeFile(pRead, pRet->firstVer);
+    if(code < 0) {
+      //TODO: set error flag
+      return -1;
+    }
+  }
+
+  code = walReadSeekFilePos(pRead, pRet->firstVer, ver);
+  if(code < 0) {
+    return -1;
+  }
+  pRead->curVersion = ver;
+   
+  return 0;
+}
+
+int32_t walReadWithHandle(SWalReadHandle *pRead, int64_t ver) {
+  int code;
+  //TODO: check wal life
+  if(pRead->curVersion != ver) {
+    walReadSeekVer(pRead, ver);   
+  }
+
+  if(!tfValid(pRead->readLogTfd)) return -1;
+
+  if(sizeof(SWalHead) != tfRead(pRead->readLogTfd, &pRead->head, sizeof(SWalHead))) {
+    return -1;
+  }
+  code = walValidHeadCksum(&pRead->head);
+  if(code != 0) {
+    return -1;
+  }
+  if(pRead->capacity < pRead->head.head.len) {
+    void* ptr = realloc(pRead, pRead->head.head.len);
+    if(ptr == NULL) {
+      return -1;
+    }
+    pRead = ptr;
+    pRead->capacity = pRead->head.head.len;
+  }
+  if(pRead->head.head.len != tfRead(pRead->readLogTfd, &pRead->head.head.body, pRead->head.head.len)) {
+    return -1;
+  }
+  code = walValidBodyCksum(&pRead->head);
+  if(code != 0) {
+    return -1;
+  }
+
+  return 0;
+}
+
 int32_t walRead(SWal *pWal, SWalHead **ppHead, int64_t ver) {
   int code;
   code = walSeekVer(pWal, ver);
@@ -42,7 +183,7 @@ int32_t walRead(SWal *pWal, SWalHead **ppHead, int64_t ver) {
     *ppHead = NULL;
     return -1;
   }
-  if(tfRead(pWal->writeLogTfd, (*ppHead)->head.cont, (*ppHead)->head.len) != (*ppHead)->head.len) {
+  if(tfRead(pWal->writeLogTfd, (*ppHead)->head.body, (*ppHead)->head.len) != (*ppHead)->head.len) {
     return -1;
   }
   //TODO: endian compatibility processing after read
diff --git a/source/libs/wal/src/walSeek.c b/source/libs/wal/src/walSeek.c
index 48272f8f327f26cd3a30147eff8c8328830ef3f3..953aae703c75764acf047851022b15c79b88cc77 100644
--- a/source/libs/wal/src/walSeek.c
+++ b/source/libs/wal/src/walSeek.c
@@ -78,10 +78,12 @@ int walChangeFile(SWal *pWal, int64_t ver) {
   code = tfClose(pWal->writeLogTfd);
   if(code != 0) {
    //TODO 
+    return -1;
   }
   code = tfClose(pWal->writeIdxTfd);
   if(code != 0) {
    //TODO 
+    return -1;
   }
   WalFileInfo tmpInfo;
   tmpInfo.firstVer = ver;
@@ -106,24 +108,19 @@ int walChangeFile(SWal *pWal, int64_t ver) {
 
   pWal->writeLogTfd = logTfd;
   pWal->writeIdxTfd = idxTfd;
-  return code;
-}
-
-int walGetVerOffset(SWal* pWal, int64_t ver) {
-  int code;
-  return 0;
+  return fileFirstVer;
 }
 
 int walSeekVer(SWal *pWal, int64_t ver) {
   int code;
-  if(ver == pWal->lastVersion) {
+  if(ver == pWal->vers.lastVer) {
     return 0;
   }
-  if(ver > pWal->lastVersion || ver < pWal->firstVersion) {
+  if(ver > pWal->vers.lastVer|| ver < pWal->vers.firstVer) {
     return -1;
   }
-  if(ver < pWal->snapshotVersion) {
-    //TODO: set flag to prevent roll back
+  if(ver < pWal->vers.snapshotVer) {
+
   }
   if(ver < walGetCurFileFirstVer(pWal) || (ver > walGetCurFileLastVer(pWal))) {
     code = walChangeFile(pWal, ver);
diff --git a/source/libs/wal/src/walUtil.c b/source/libs/wal/src/walUtil.c
index c88cc918fe42c30564abe3feb5ae273386d1b994..849d0c3e5189acdd6fdd50a6ef3210351ffbb64d 100644
--- a/source/libs/wal/src/walUtil.c
+++ b/source/libs/wal/src/walUtil.c
@@ -17,6 +17,7 @@
 #include "os.h"
 #include "walInt.h"
 
+#if 0
 int32_t walGetNextFile(SWal *pWal, int64_t *nextFileId) {
   int64_t curFileId = *nextFileId;
   int64_t minFileId = INT64_MAX;
@@ -116,3 +117,4 @@ int32_t walGetNewFile(SWal *pWal, int64_t *newFileId) {
 
   return 0;
 }
+#endif
diff --git a/source/libs/wal/src/walWrite.c b/source/libs/wal/src/walWrite.c
index 972ac5c68240cd9d5739c7f82e2e4fe154a54934..44e8cec153f7791e7741244c8f1c5d804ef72e24 100644
--- a/source/libs/wal/src/walWrite.c
+++ b/source/libs/wal/src/walWrite.c
@@ -114,22 +114,22 @@ void walRemoveAllOldFiles(void *handle) {
 #endif
 
 int32_t walCommit(SWal *pWal, int64_t ver) {
-  ASSERT(pWal->commitVersion >= pWal->snapshotVersion);
-  ASSERT(pWal->commitVersion <= pWal->lastVersion);
-  if(ver < pWal->commitVersion || ver > pWal->lastVersion) {
+  ASSERT(pWal->vers.commitVer >= pWal->vers.snapshotVer);
+  ASSERT(pWal->vers.commitVer <= pWal->vers.lastVer);
+  if(ver < pWal->vers.commitVer || ver > pWal->vers.lastVer) {
     return -1;
   }
-  pWal->commitVersion = ver;
+  pWal->vers.commitVer = ver;
   return 0;
 }
 
 int32_t walRollback(SWal *pWal, int64_t ver) {
   int code;
   char fnameStr[WAL_FILE_LEN];
-  if(ver == pWal->lastVersion) {
+  if(ver == pWal->vers.lastVer) {
     return 0;
   }
-  if(ver > pWal->lastVersion || ver < pWal->commitVersion) {
+  if(ver > pWal->vers.lastVer || ver < pWal->vers.commitVer) {
     return -1;
   }
   pthread_mutex_lock(&pWal->mutex);
@@ -220,7 +220,7 @@ int32_t walRollback(SWal *pWal, int64_t ver) {
   if(code < 0) {
     return -1;
   }
-  pWal->lastVersion = ver - 1;
+  pWal->vers.lastVer = ver - 1;
   ((WalFileInfo*)taosArrayGetLast(pWal->fileInfoSet))->lastVer = ver - 1;
   ((WalFileInfo*)taosArrayGetLast(pWal->fileInfoSet))->fileSize = entry.offset;
 
@@ -230,9 +230,9 @@ int32_t walRollback(SWal *pWal, int64_t ver) {
 }
 
 int32_t walBeginTakeSnapshot(SWal* pWal, int64_t ver) {
-  pWal->snapshottingVer = ver;
+  pWal->vers.verInSnapshotting = ver;
   //check file rolling
-  if(pWal->retentionPeriod == 0) {
+  if(pWal->cfg.retentionPeriod == 0) {
     walRoll(pWal);
   }
 
@@ -240,10 +240,10 @@ int32_t walBeginTakeSnapshot(SWal* pWal, int64_t ver) {
 }
 
 int32_t walEndTakeSnapshot(SWal *pWal) {
-  int64_t ver = pWal->snapshottingVer;
+  int64_t ver = pWal->vers.verInSnapshotting;
   if(ver == -1) return -1;
 
-  pWal->snapshotVersion = ver;
+  pWal->vers.snapshotVer = ver;
   int ts = taosGetTimestampSec();
 
   int deleteCnt = 0;
@@ -257,8 +257,8 @@ int32_t walEndTakeSnapshot(SWal *pWal) {
   }
   //iterate files, until the searched result
   for(WalFileInfo* iter = pWal->fileInfoSet->pData; iter < pInfo; iter++) {
-    if(pWal->totSize > pWal->retentionSize ||
-        iter->closeTs + pWal->retentionPeriod > ts) {
+    if(pWal->totSize > pWal->cfg.retentionSize ||
+        iter->closeTs + pWal->cfg.retentionPeriod > ts) {
       //delete according to file size or close time
       deleteCnt++;
       newTotSize -= iter->fileSize;
@@ -278,13 +278,13 @@ int32_t walEndTakeSnapshot(SWal *pWal) {
   taosArrayPopFrontBatch(pWal->fileInfoSet, deleteCnt); 
   if(taosArrayGetSize(pWal->fileInfoSet) == 0) {
     pWal->writeCur = -1;
-    pWal->firstVersion = -1;
+    pWal->vers.firstVer = -1;
   } else {
-    pWal->firstVersion = ((WalFileInfo*)taosArrayGet(pWal->fileInfoSet, 0))->firstVer;
+    pWal->vers.firstVer = ((WalFileInfo*)taosArrayGet(pWal->fileInfoSet, 0))->firstVer;
   }
   pWal->writeCur = taosArrayGetSize(pWal->fileInfoSet) - 1;;
   pWal->totSize = newTotSize;
-  pWal->snapshottingVer = -1;
+  pWal->vers.verInSnapshotting = -1;
 
   //save snapshot ver, commit ver
   int code = walWriteMeta(pWal);
@@ -311,7 +311,7 @@ int walRoll(SWal *pWal) {
   }
   int64_t idxTfd, logTfd;
   //create new file
-  int64_t newFileFirstVersion = pWal->lastVersion + 1;
+  int64_t newFileFirstVersion = pWal->vers.lastVer + 1;
   char fnameStr[WAL_FILE_LEN];
   walBuildIdxName(pWal, newFileFirstVersion, fnameStr);
   idxTfd = tfOpenCreateWrite(fnameStr);
@@ -357,18 +357,18 @@ int64_t walWrite(SWal *pWal, int64_t index, uint8_t msgType, const void *body, i
   int code = 0;
 
   // no wal
-  if (pWal->level == TAOS_WAL_NOLOG) return 0;
+  if (pWal->cfg.level == TAOS_WAL_NOLOG) return 0;
 
-  if (index == pWal->lastVersion + 1) {
+  if (index == pWal->vers.lastVer + 1) {
     if(taosArrayGetSize(pWal->fileInfoSet) == 0) {
-      pWal->firstVersion = index;
+      pWal->vers.firstVer = index;
       code = walRoll(pWal);
       ASSERT(code == 0);
     } else {
       int64_t passed = walGetSeq() - pWal->lastRollSeq;
-      if(pWal->rollPeriod != -1 && pWal->rollPeriod != 0 && passed > pWal->rollPeriod) {
+      if(pWal->cfg.rollPeriod != -1 && pWal->cfg.rollPeriod != 0 && passed > pWal->cfg.rollPeriod) {
         walRoll(pWal);
-      } else if(pWal->segSize != -1 && pWal->segSize != 0 && walGetLastFileSize(pWal) > pWal->segSize) {
+      } else if(pWal->cfg.segSize != -1 && pWal->cfg.segSize != 0 && walGetLastFileSize(pWal) > pWal->cfg.segSize) {
         walRoll(pWal);
       }
     }
@@ -380,23 +380,23 @@ int64_t walWrite(SWal *pWal, int64_t index, uint8_t msgType, const void *body, i
   /*if (!tfValid(pWal->curLogTfd)) return 0;*/
 
   pthread_mutex_lock(&pWal->mutex);
-  pWal->head.head.version = index;
+  pWal->writeHead.head.version = index;
 
-  pWal->head.head.len = bodyLen;
-  pWal->head.head.msgType = msgType;
-  pWal->head.cksumHead = walCalcHeadCksum(&pWal->head);
-  pWal->head.cksumBody = walCalcBodyCksum(body, bodyLen);
+  pWal->writeHead.head.len = bodyLen;
+  pWal->writeHead.head.msgType = msgType;
+  pWal->writeHead.cksumHead = walCalcHeadCksum(&pWal->writeHead);
+  pWal->writeHead.cksumBody = walCalcBodyCksum(body, bodyLen);
 
-  if (tfWrite(pWal->writeLogTfd, &pWal->head, sizeof(SWalHead)) != sizeof(SWalHead)) {
+  if (tfWrite(pWal->writeLogTfd, &pWal->writeHead, sizeof(SWalHead)) != sizeof(SWalHead)) {
     //ftruncate
     code = TAOS_SYSTEM_ERROR(errno);
-    wError("vgId:%d, file:%"PRId64".log, failed to write since %s", pWal->vgId, walGetLastFileFirstVer(pWal), strerror(errno));
+    wError("vgId:%d, file:%"PRId64".log, failed to write since %s", pWal->cfg.vgId, walGetLastFileFirstVer(pWal), strerror(errno));
   }
 
   if (tfWrite(pWal->writeLogTfd, &body, bodyLen) != bodyLen) {
     //ftruncate
     code = TAOS_SYSTEM_ERROR(errno);
-    wError("vgId:%d, file:%"PRId64".log, failed to write since %s", pWal->vgId, walGetLastFileFirstVer(pWal), strerror(errno));
+    wError("vgId:%d, file:%"PRId64".log, failed to write since %s", pWal->cfg.vgId, walGetLastFileFirstVer(pWal), strerror(errno));
   }
   code = walWriteIndex(pWal, index, walGetCurFileOffset(pWal));
   if(code != 0) {
@@ -405,7 +405,7 @@ int64_t walWrite(SWal *pWal, int64_t index, uint8_t msgType, const void *body, i
   }
 
   //set status
-  pWal->lastVersion = index;
+  pWal->vers.lastVer = index;
   pWal->totSize += sizeof(SWalHead) + bodyLen;
   walGetCurFileInfo(pWal)->lastVer = index;
   walGetCurFileInfo(pWal)->fileSize += sizeof(SWalHead) + bodyLen;
@@ -416,10 +416,10 @@ int64_t walWrite(SWal *pWal, int64_t index, uint8_t msgType, const void *body, i
 }
 
 void walFsync(SWal *pWal, bool forceFsync) {
-  if (forceFsync || (pWal->level == TAOS_WAL_FSYNC && pWal->fsyncPeriod == 0)) {
-    wTrace("vgId:%d, fileId:%"PRId64".log, do fsync", pWal->vgId, walGetCurFileFirstVer(pWal));
+  if (forceFsync || (pWal->cfg.level == TAOS_WAL_FSYNC && pWal->cfg.fsyncPeriod == 0)) {
+    wTrace("vgId:%d, fileId:%"PRId64".log, do fsync", pWal->cfg.vgId, walGetCurFileFirstVer(pWal));
     if (tfFsync(pWal->writeLogTfd) < 0) {
-      wError("vgId:%d, file:%"PRId64".log, fsync failed since %s", pWal->vgId, walGetCurFileFirstVer(pWal), strerror(errno));
+      wError("vgId:%d, file:%"PRId64".log, fsync failed since %s", pWal->cfg.vgId, walGetCurFileFirstVer(pWal), strerror(errno));
     }
   }
 }
@@ -492,29 +492,29 @@ int32_t walGetWalFile(void *handle, char *fileName, int64_t *fileId) {
 }
 #endif
 
-static int walValidateOffset(SWal* pWal, int64_t ver) {
-  int code = 0;
-  SWalHead *pHead = NULL;
-  code = (int)walRead(pWal, &pHead, ver);
-  if(pHead->head.version != ver) {
-    return -1;
-  }
-  return 0;
-}
+/*static int walValidateOffset(SWal* pWal, int64_t ver) {*/
+  /*int code = 0;*/
+  /*SWalHead *pHead = NULL;*/
+  /*code = (int)walRead(pWal, &pHead, ver);*/
+  /*if(pHead->head.version != ver) {*/
+    /*return -1;*/
+  /*}*/
+  /*return 0;*/
+/*}*/
 
-static int64_t walGetOffset(SWal* pWal, int64_t ver) {
-  int code = walSeekVer(pWal, ver);
-  if(code != 0) {
-    return -1;
-  }
+/*static int64_t walGetOffset(SWal* pWal, int64_t ver) {*/
+  /*int code = walSeekVer(pWal, ver);*/
+  /*if(code != 0) {*/
+    /*return -1;*/
+  /*}*/
 
-  code = walValidateOffset(pWal, ver);
-  if(code != 0) {
-    return -1;
-  }
+  /*code = walValidateOffset(pWal, ver);*/
+  /*if(code != 0) {*/
+    /*return -1;*/
+  /*}*/
 
-  return 0;
-}
+  /*return 0;*/
+/*}*/
 
 #if 0
 static int32_t walSkipCorruptedRecord(SWal *pWal, SWalHead *pHead, int64_t tfd, int64_t *offset) {
diff --git a/source/libs/wal/test/walMetaTest.cpp b/source/libs/wal/test/walMetaTest.cpp
index c81343d03b85d27e1c57444db23fbba5e9402300..504f1ada3f7d1b66135879538a173caef43e1f2a 100644
--- a/source/libs/wal/test/walMetaTest.cpp
+++ b/source/libs/wal/test/walMetaTest.cpp
@@ -24,7 +24,7 @@ class WalCleanEnv : public ::testing::Test {
       pCfg->segSize = -1;
       pCfg->retentionPeriod = 0;
       pCfg->retentionSize = 0;
-      pCfg->walLevel = TAOS_WAL_FSYNC;
+      pCfg->level = TAOS_WAL_FSYNC;
       pWal = walOpen(pathName, pCfg);
       free(pCfg);
       ASSERT(pWal != NULL);
@@ -56,7 +56,7 @@ class WalCleanDeleteEnv : public ::testing::Test {
       memset(pCfg, 0, sizeof(SWalCfg));
       pCfg->retentionPeriod = 0;
       pCfg->retentionSize = 0;
-      pCfg->walLevel = TAOS_WAL_FSYNC;
+      pCfg->level = TAOS_WAL_FSYNC;
       pWal = walOpen(pathName, pCfg);
       free(pCfg);
       ASSERT(pWal != NULL);
@@ -95,7 +95,7 @@ class WalKeepEnv : public ::testing::Test {
       pCfg->segSize = -1;
       pCfg->retentionPeriod = 0;
       pCfg->retentionSize = 0;
-      pCfg->walLevel = TAOS_WAL_FSYNC;
+      pCfg->level = TAOS_WAL_FSYNC;
       pWal = walOpen(pathName, pCfg);
       free(pCfg);
       ASSERT(pWal != NULL);
@@ -164,18 +164,18 @@ TEST_F(WalKeepEnv, readOldMeta) {
   for(int i = 0; i < 10; i++) {
     code = walWrite(pWal, i, i+1, (void*)ranStr, len); 
     ASSERT_EQ(code, 0);
-    ASSERT_EQ(pWal->lastVersion, i);
+    ASSERT_EQ(pWal->vers.lastVer, i);
     code = walWrite(pWal, i+2, i, (void*)ranStr, len);
     ASSERT_EQ(code, -1);
-    ASSERT_EQ(pWal->lastVersion, i);
+    ASSERT_EQ(pWal->vers.lastVer, i);
   }
   char* oldss = walMetaSerialize(pWal);
 
   TearDown();
   SetUp();
 
-  ASSERT_EQ(pWal->firstVersion, 0);
-  ASSERT_EQ(pWal->lastVersion, 9);
+  ASSERT_EQ(pWal->vers.firstVer, 0);
+  ASSERT_EQ(pWal->vers.lastVer, 9);
 
   char* newss = walMetaSerialize(pWal);
 
@@ -195,10 +195,10 @@ TEST_F(WalCleanEnv, write) {
   for(int i = 0; i < 10; i++) {
     code = walWrite(pWal, i, i+1, (void*)ranStr, len); 
     ASSERT_EQ(code, 0);
-    ASSERT_EQ(pWal->lastVersion, i);
+    ASSERT_EQ(pWal->vers.lastVer, i);
     code = walWrite(pWal, i+2, i, (void*)ranStr, len);
     ASSERT_EQ(code, -1);
-    ASSERT_EQ(pWal->lastVersion, i);
+    ASSERT_EQ(pWal->vers.lastVer, i);
   }
   code = walWriteMeta(pWal);
   ASSERT_EQ(code, 0);
@@ -211,14 +211,14 @@ TEST_F(WalCleanEnv, rollback) {
   for(int i = 0; i < 10; i++) {
     code = walWrite(pWal, i, i+1, (void*)ranStr, len); 
     ASSERT_EQ(code, 0);
-    ASSERT_EQ(pWal->lastVersion, i);
+    ASSERT_EQ(pWal->vers.lastVer, i);
   }
   code = walRollback(pWal, 5);
   ASSERT_EQ(code, 0);
-  ASSERT_EQ(pWal->lastVersion, 4);
+  ASSERT_EQ(pWal->vers.lastVer, 4);
   code = walRollback(pWal, 3);
   ASSERT_EQ(code, 0);
-  ASSERT_EQ(pWal->lastVersion, 2);
+  ASSERT_EQ(pWal->vers.lastVer, 2);
   code = walWriteMeta(pWal);
   ASSERT_EQ(code, 0);
 }
@@ -231,16 +231,16 @@ TEST_F(WalCleanDeleteEnv, roll) {
   for(i = 0; i < 100; i++) {
     code = walWrite(pWal, i, 0, (void*)ranStr, len);
     ASSERT_EQ(code, 0);
-    ASSERT_EQ(pWal->lastVersion, i);
+    ASSERT_EQ(pWal->vers.lastVer, i);
     code = walCommit(pWal, i);
-    ASSERT_EQ(pWal->commitVersion, i);
+    ASSERT_EQ(pWal->vers.commitVer, i);
   }
 
   walBeginTakeSnapshot(pWal, i-1);
-  ASSERT_EQ(pWal->snapshottingVer, i-1); 
+  ASSERT_EQ(pWal->vers.verInSnapshotting, i-1);
   walEndTakeSnapshot(pWal);
-  ASSERT_EQ(pWal->snapshotVersion, i-1); 
-  ASSERT_EQ(pWal->snapshottingVer, -1); 
+  ASSERT_EQ(pWal->vers.snapshotVer, i-1);
+  ASSERT_EQ(pWal->vers.verInSnapshotting, -1);
 
   code = walWrite(pWal, 5, 0, (void*)ranStr, len);
   ASSERT_NE(code, 0);
@@ -249,7 +249,7 @@ TEST_F(WalCleanDeleteEnv, roll) {
     code = walWrite(pWal, i, 0, (void*)ranStr, len);
     ASSERT_EQ(code, 0);
     code = walCommit(pWal, i);
-    ASSERT_EQ(pWal->commitVersion, i);
+    ASSERT_EQ(pWal->vers.commitVer, i);
   }
 
   //code = walWriteMeta(pWal);
diff --git a/source/util/src/tarray.c b/source/util/src/tarray.c
index 6216188496be91d5a2d7e603a854118b1dc60f8f..581a7973432edaf20f8ff986816abd40bd12d816 100644
--- a/source/util/src/tarray.c
+++ b/source/util/src/tarray.c
@@ -250,7 +250,7 @@ void taosArrayPopFrontBatch(SArray* pArray, size_t cnt) {
   if(pArray->size == 0) {
     return;
   }
-  memmove(pArray->pData, (char*)pArray->pData + cnt * pArray->elemSize, pArray->size);
+  memmove(pArray->pData, (char*)pArray->pData + cnt * pArray->elemSize, pArray->size * pArray->elemSize);
 }
 
 void taosArrayPopTailBatch(SArray* pArray, size_t cnt) {