diff --git a/include/common/tmsgdef.h b/include/common/tmsgdef.h
index f4890206fe572be40704959bb4a846f9363fb25a..7ca552f179fe6da0bd189797ff0c33817c91dbf0 100644
--- a/include/common/tmsgdef.h
+++ b/include/common/tmsgdef.h
@@ -274,8 +274,8 @@ enum {
   TD_DEF_MSG_TYPE(TDMT_SYNC_HEARTBEAT, "sync-heartbeat", NULL, NULL)
   TD_DEF_MSG_TYPE(TDMT_SYNC_HEARTBEAT_REPLY, "sync-heartbeat-reply", NULL, NULL)
   TD_DEF_MSG_TYPE(TDMT_SYNC_LOCAL_CMD, "sync-local-cmd", NULL, NULL)
-  TD_DEF_MSG_TYPE(TDMT_SYNC_PRE_SNAPSHOT, "sync-pre-snapshot", NULL, NULL)
-  TD_DEF_MSG_TYPE(TDMT_SYNC_PRE_SNAPSHOT_REPLY, "sync-pre-snapshot-reply", NULL, NULL)
+  TD_DEF_MSG_TYPE(TDMT_SYNC_PRE_SNAPSHOT, "sync-pre-snapshot", NULL, NULL)             // no longer used
+  TD_DEF_MSG_TYPE(TDMT_SYNC_PRE_SNAPSHOT_REPLY, "sync-pre-snapshot-reply", NULL, NULL) // no longer used
   TD_DEF_MSG_TYPE(TDMT_SYNC_MAX_MSG, "sync-max", NULL, NULL)
   
   TD_NEW_MSG_SEG(TDMT_VND_STREAM_MSG)
diff --git a/source/dnode/mgmt/mgmt_mnode/src/mmHandle.c b/source/dnode/mgmt/mgmt_mnode/src/mmHandle.c
index a322f7680042383db31a0e41693ab78c610709b8..16fe6c1b91f8a7788ad4a48993b337fe6bc7b160 100644
--- a/source/dnode/mgmt/mgmt_mnode/src/mmHandle.c
+++ b/source/dnode/mgmt/mgmt_mnode/src/mmHandle.c
@@ -195,7 +195,6 @@ SArray *mmGetMsgHandles() {
   if (dmSetMgmtHandle(pArray, TDMT_SYNC_SNAPSHOT_RSP, mmPutMsgToSyncQueue, 1) == NULL) goto _OVER;
   if (dmSetMgmtHandle(pArray, TDMT_SYNC_PRE_SNAPSHOT, mmPutMsgToSyncQueue, 1) == NULL) goto _OVER;
   if (dmSetMgmtHandle(pArray, TDMT_SYNC_PRE_SNAPSHOT_REPLY, mmPutMsgToSyncQueue, 1) == NULL) goto _OVER;
-
   if (dmSetMgmtHandle(pArray, TDMT_SYNC_HEARTBEAT, mmPutMsgToSyncCtrlQueue, 1) == NULL) goto _OVER;
   if (dmSetMgmtHandle(pArray, TDMT_SYNC_HEARTBEAT_REPLY, mmPutMsgToSyncCtrlQueue, 1) == NULL) goto _OVER;
 
diff --git a/source/libs/sync/inc/syncMessage.h b/source/libs/sync/inc/syncMessage.h
index 4d66b3713791d1128b9c159806b1cb2d0bb6043f..a38b7c10ffc3d35ab8d2be10e899aaba32ae36b7 100644
--- a/source/libs/sync/inc/syncMessage.h
+++ b/source/libs/sync/inc/syncMessage.h
@@ -112,7 +112,6 @@ typedef struct SyncAppendEntriesReply {
   int64_t   startTime;
 } SyncAppendEntriesReply;
 
-// ---------------------------------------------
 typedef struct SyncHeartbeat {
   uint32_t bytes;
   int32_t  vgId;
@@ -149,28 +148,8 @@ typedef struct SyncPreSnapshot {
 
   // private data
   SyncTerm term;
-
 } SyncPreSnapshot;
 
-SyncPreSnapshot* syncPreSnapshotBuild(int32_t vgId);
-void             syncPreSnapshotDestroy(SyncPreSnapshot* pMsg);
-void             syncPreSnapshotSerialize(const SyncPreSnapshot* pMsg, char* buf, uint32_t bufLen);
-void             syncPreSnapshotDeserialize(const char* buf, uint32_t len, SyncPreSnapshot* pMsg);
-char*            syncPreSnapshotSerialize2(const SyncPreSnapshot* pMsg, uint32_t* len);
-SyncPreSnapshot* syncPreSnapshotDeserialize2(const char* buf, uint32_t len);
-void             syncPreSnapshot2RpcMsg(const SyncPreSnapshot* pMsg, SRpcMsg* pRpcMsg);
-void             syncPreSnapshotFromRpcMsg(const SRpcMsg* pRpcMsg, SyncPreSnapshot* pMsg);
-SyncPreSnapshot* syncPreSnapshotFromRpcMsg2(const SRpcMsg* pRpcMsg);
-cJSON*           syncPreSnapshot2Json(const SyncPreSnapshot* pMsg);
-char*            syncPreSnapshot2Str(const SyncPreSnapshot* pMsg);
-
-// for debug ----------------------
-void syncPreSnapshotPrint(const SyncPreSnapshot* pMsg);
-void syncPreSnapshotPrint2(char* s, const SyncPreSnapshot* pMsg);
-void syncPreSnapshotLog(const SyncPreSnapshot* pMsg);
-void syncPreSnapshotLog2(char* s, const SyncPreSnapshot* pMsg);
-
-// ---------------------------------------------
 typedef struct SyncPreSnapshotReply {
   uint32_t bytes;
   int32_t  vgId;
@@ -181,28 +160,8 @@ typedef struct SyncPreSnapshotReply {
   // private data
   SyncTerm  term;
   SyncIndex snapStart;
-
 } SyncPreSnapshotReply;
 
-SyncPreSnapshotReply* syncPreSnapshotReplyBuild(int32_t vgId);
-void                  syncPreSnapshotReplyDestroy(SyncPreSnapshotReply* pMsg);
-void                  syncPreSnapshotReplySerialize(const SyncPreSnapshotReply* pMsg, char* buf, uint32_t bufLen);
-void                  syncPreSnapshotReplyDeserialize(const char* buf, uint32_t len, SyncPreSnapshotReply* pMsg);
-char*                 syncPreSnapshotReplySerialize2(const SyncPreSnapshotReply* pMsg, uint32_t* len);
-SyncPreSnapshotReply* syncPreSnapshotReplyDeserialize2(const char* buf, uint32_t len);
-void                  syncPreSnapshotReply2RpcMsg(const SyncPreSnapshotReply* pMsg, SRpcMsg* pRpcMsg);
-void                  syncPreSnapshotReplyFromRpcMsg(const SRpcMsg* pRpcMsg, SyncPreSnapshotReply* pMsg);
-SyncPreSnapshotReply* syncPreSnapshotReplyFromRpcMsg2(const SRpcMsg* pRpcMsg);
-cJSON*                syncPreSnapshotReply2Json(const SyncPreSnapshotReply* pMsg);
-char*                 syncPreSnapshotReply2Str(const SyncPreSnapshotReply* pMsg);
-
-// for debug ----------------------
-void syncPreSnapshotReplyPrint(const SyncPreSnapshotReply* pMsg);
-void syncPreSnapshotReplyPrint2(char* s, const SyncPreSnapshotReply* pMsg);
-void syncPreSnapshotReplyLog(const SyncPreSnapshotReply* pMsg);
-void syncPreSnapshotReplyLog2(char* s, const SyncPreSnapshotReply* pMsg);
-
-// ---------------------------------------------
 typedef struct SyncApplyMsg {
   uint32_t   bytes;
   int32_t    vgId;
@@ -375,9 +334,6 @@ int32_t syncNodeOnRequestVoteReply(SSyncNode* pNode, const SRpcMsg* pMsg);
 int32_t syncNodeOnAppendEntries(SSyncNode* pNode, const SRpcMsg* pMsg);
 int32_t syncNodeOnAppendEntriesReply(SSyncNode* ths, const SRpcMsg* pMsg);
 
-int32_t syncNodeOnPreSnapshot(SSyncNode* ths, SyncPreSnapshot* pMsg);
-int32_t syncNodeOnPreSnapshotReply(SSyncNode* ths, SyncPreSnapshotReply* pMsg);
-
 int32_t syncNodeOnSnapshot(SSyncNode* ths, SyncSnapshotSend* pMsg);
 int32_t syncNodeOnSnapshotReply(SSyncNode* ths, SyncSnapshotRsp* pMsg);
 
@@ -404,6 +360,8 @@ int32_t syncBuildAppendEntries(SRpcMsg* pMsg, int32_t dataLen, int32_t vgId);
 int32_t syncBuildAppendEntriesReply(SRpcMsg* pMsg, int32_t vgId);
 int32_t syncBuildHeartbeat(SRpcMsg* pMsg, int32_t vgId);
 int32_t syncBuildHeartbeatReply(SRpcMsg* pMsg, int32_t vgId);
+int32_t syncBuildPreSnapshot(SRpcMsg* pMsg, int32_t vgId);
+int32_t syncBuildPreSnapshotReply(SRpcMsg* pMsg, int32_t vgId);
 
 #ifdef __cplusplus
 }
diff --git a/source/libs/sync/src/syncMessage.c b/source/libs/sync/src/syncMessage.c
index cc68d370a86c87647d8a99737516a1cb1d6c5e46..26bedb2b6614f19f2e3d5b5c71a240deb58a413b 100644
--- a/source/libs/sync/src/syncMessage.c
+++ b/source/libs/sync/src/syncMessage.c
@@ -189,301 +189,38 @@ int32_t syncBuildHeartbeatReply(SRpcMsg* pMsg, int32_t vgId) {
   return 0;
 }
 
-// ---- message process SyncPreSnapshot----
-SyncPreSnapshot* syncPreSnapshotBuild(int32_t vgId) {
-  uint32_t         bytes = sizeof(SyncPreSnapshot);
-  SyncPreSnapshot* pMsg = taosMemoryMalloc(bytes);
-  memset(pMsg, 0, bytes);
-  pMsg->bytes = bytes;
-  pMsg->vgId = vgId;
+int32_t syncBuildPreSnapshot(SRpcMsg* pMsg, int32_t vgId) {
+  int32_t bytes = sizeof(SyncPreSnapshot);
+  pMsg->pCont = rpcMallocCont(bytes);
   pMsg->msgType = TDMT_SYNC_PRE_SNAPSHOT;
-  return pMsg;
-}
-
-void syncPreSnapshotDestroy(SyncPreSnapshot* pMsg) {
-  if (pMsg != NULL) {
-    taosMemoryFree(pMsg);
-  }
-}
-
-void syncPreSnapshotSerialize(const SyncPreSnapshot* pMsg, char* buf, uint32_t bufLen) {
-  ASSERT(pMsg->bytes <= bufLen);
-  memcpy(buf, pMsg, pMsg->bytes);
-}
-
-void syncPreSnapshotDeserialize(const char* buf, uint32_t len, SyncPreSnapshot* pMsg) {
-  memcpy(pMsg, buf, len);
-  ASSERT(len == pMsg->bytes);
-}
-
-char* syncPreSnapshotSerialize2(const SyncPreSnapshot* pMsg, uint32_t* len) {
-  char* buf = taosMemoryMalloc(pMsg->bytes);
-  ASSERT(buf != NULL);
-  syncPreSnapshotSerialize(pMsg, buf, pMsg->bytes);
-  if (len != NULL) {
-    *len = pMsg->bytes;
-  }
-  return buf;
-}
-
-SyncPreSnapshot* syncPreSnapshotDeserialize2(const char* buf, uint32_t len) {
-  uint32_t         bytes = *((uint32_t*)buf);
-  SyncPreSnapshot* pMsg = taosMemoryMalloc(bytes);
-  ASSERT(pMsg != NULL);
-  syncPreSnapshotDeserialize(buf, len, pMsg);
-  ASSERT(len == pMsg->bytes);
-  return pMsg;
-}
-
-void syncPreSnapshot2RpcMsg(const SyncPreSnapshot* pMsg, SRpcMsg* pRpcMsg) {
-  memset(pRpcMsg, 0, sizeof(*pRpcMsg));
-  pRpcMsg->msgType = pMsg->msgType;
-  pRpcMsg->contLen = pMsg->bytes;
-  pRpcMsg->pCont = rpcMallocCont(pRpcMsg->contLen);
-  syncPreSnapshotSerialize(pMsg, pRpcMsg->pCont, pRpcMsg->contLen);
-}
-
-void syncPreSnapshotFromRpcMsg(const SRpcMsg* pRpcMsg, SyncPreSnapshot* pMsg) {
-  syncPreSnapshotDeserialize(pRpcMsg->pCont, pRpcMsg->contLen, pMsg);
-}
-
-SyncPreSnapshot* syncPreSnapshotFromRpcMsg2(const SRpcMsg* pRpcMsg) {
-  SyncPreSnapshot* pMsg = syncPreSnapshotDeserialize2(pRpcMsg->pCont, pRpcMsg->contLen);
-  ASSERT(pMsg != NULL);
-  return pMsg;
-}
-
-cJSON* syncPreSnapshot2Json(const SyncPreSnapshot* pMsg) {
-  char   u64buf[128] = {0};
-  cJSON* pRoot = cJSON_CreateObject();
-
-  if (pMsg != NULL) {
-    cJSON_AddNumberToObject(pRoot, "bytes", pMsg->bytes);
-    cJSON_AddNumberToObject(pRoot, "vgId", pMsg->vgId);
-    cJSON_AddNumberToObject(pRoot, "msgType", pMsg->msgType);
-
-    cJSON* pSrcId = cJSON_CreateObject();
-    snprintf(u64buf, sizeof(u64buf), "%" PRIu64, pMsg->srcId.addr);
-    cJSON_AddStringToObject(pSrcId, "addr", u64buf);
-    {
-      uint64_t u64 = pMsg->srcId.addr;
-      cJSON*   pTmp = pSrcId;
-      char     host[128] = {0};
-      uint16_t port;
-      syncUtilU642Addr(u64, host, sizeof(host), &port);
-      cJSON_AddStringToObject(pTmp, "addr_host", host);
-      cJSON_AddNumberToObject(pTmp, "addr_port", port);
-    }
-    cJSON_AddNumberToObject(pSrcId, "vgId", pMsg->srcId.vgId);
-    cJSON_AddItemToObject(pRoot, "srcId", pSrcId);
-
-    cJSON* pDestId = cJSON_CreateObject();
-    snprintf(u64buf, sizeof(u64buf), "%" PRIu64, pMsg->destId.addr);
-    cJSON_AddStringToObject(pDestId, "addr", u64buf);
-    {
-      uint64_t u64 = pMsg->destId.addr;
-      cJSON*   pTmp = pDestId;
-      char     host[128] = {0};
-      uint16_t port;
-      syncUtilU642Addr(u64, host, sizeof(host), &port);
-      cJSON_AddStringToObject(pTmp, "addr_host", host);
-      cJSON_AddNumberToObject(pTmp, "addr_port", port);
-    }
-    cJSON_AddNumberToObject(pDestId, "vgId", pMsg->destId.vgId);
-    cJSON_AddItemToObject(pRoot, "destId", pDestId);
-
-    snprintf(u64buf, sizeof(u64buf), "%" PRIu64, pMsg->term);
-    cJSON_AddStringToObject(pRoot, "term", u64buf);
+  pMsg->contLen = bytes;
+  if (pMsg->pCont == NULL) {
+    terrno = TSDB_CODE_OUT_OF_MEMORY;
+    return -1;
   }
 
-  cJSON* pJson = cJSON_CreateObject();
-  cJSON_AddItemToObject(pJson, "SyncPreSnapshot", pRoot);
-  return pJson;
-}
-
-char* syncPreSnapshot2Str(const SyncPreSnapshot* pMsg) {
-  cJSON* pJson = syncPreSnapshot2Json(pMsg);
-  char*  serialized = cJSON_Print(pJson);
-  cJSON_Delete(pJson);
-  return serialized;
-}
-
-void syncPreSnapshotPrint(const SyncPreSnapshot* pMsg) {
-  char* serialized = syncPreSnapshot2Str(pMsg);
-  printf("syncPreSnapshotPrint | len:%d | %s \n", (int32_t)strlen(serialized), serialized);
-  fflush(NULL);
-  taosMemoryFree(serialized);
-}
-
-void syncPreSnapshotPrint2(char* s, const SyncPreSnapshot* pMsg) {
-  char* serialized = syncPreSnapshot2Str(pMsg);
-  printf("syncPreSnapshotPrint2 | len:%d | %s | %s \n", (int32_t)strlen(serialized), s, serialized);
-  fflush(NULL);
-  taosMemoryFree(serialized);
-}
-
-void syncPreSnapshotLog(const SyncPreSnapshot* pMsg) {
-  char* serialized = syncPreSnapshot2Str(pMsg);
-  sTrace("syncPreSnapshotLog | len:%d | %s", (int32_t)strlen(serialized), serialized);
-  taosMemoryFree(serialized);
-}
-
-void syncPreSnapshotLog2(char* s, const SyncPreSnapshot* pMsg) {
-  if (gRaftDetailLog) {
-    char* serialized = syncPreSnapshot2Str(pMsg);
-    sTrace("syncPreSnapshotLog2 | len:%d | %s | %s", (int32_t)strlen(serialized), s, serialized);
-    taosMemoryFree(serialized);
-  }
+  SyncPreSnapshot* pPreSnapshot = pMsg->pCont;
+  pPreSnapshot->bytes = bytes;
+  pPreSnapshot->msgType = TDMT_SYNC_PRE_SNAPSHOT;
+  pPreSnapshot->vgId = vgId;
+  return 0;
 }
 
-// ---- message process SyncPreSnapshotReply----
-SyncPreSnapshotReply* syncPreSnapshotReplyBuild(int32_t vgId) {
-  uint32_t              bytes = sizeof(SyncPreSnapshotReply);
-  SyncPreSnapshotReply* pMsg = taosMemoryMalloc(bytes);
-  memset(pMsg, 0, bytes);
-  pMsg->bytes = bytes;
-  pMsg->vgId = vgId;
+int32_t syncBuildPreSnapshotReply(SRpcMsg* pMsg, int32_t vgId) {
+  int32_t bytes = sizeof(SyncPreSnapshotReply);
+  pMsg->pCont = rpcMallocCont(bytes);
   pMsg->msgType = TDMT_SYNC_PRE_SNAPSHOT_REPLY;
-  return pMsg;
-}
-
-void syncPreSnapshotReplyDestroy(SyncPreSnapshotReply* pMsg) {
-  if (pMsg != NULL) {
-    taosMemoryFree(pMsg);
-  }
-}
-
-void syncPreSnapshotReplySerialize(const SyncPreSnapshotReply* pMsg, char* buf, uint32_t bufLen) {
-  ASSERT(pMsg->bytes <= bufLen);
-  memcpy(buf, pMsg, pMsg->bytes);
-}
-
-void syncPreSnapshotReplyDeserialize(const char* buf, uint32_t len, SyncPreSnapshotReply* pMsg) {
-  memcpy(pMsg, buf, len);
-  ASSERT(len == pMsg->bytes);
-}
-
-char* syncPreSnapshotReplySerialize2(const SyncPreSnapshotReply* pMsg, uint32_t* len) {
-  char* buf = taosMemoryMalloc(pMsg->bytes);
-  ASSERT(buf != NULL);
-  syncPreSnapshotReplySerialize(pMsg, buf, pMsg->bytes);
-  if (len != NULL) {
-    *len = pMsg->bytes;
-  }
-  return buf;
-}
-
-SyncPreSnapshotReply* syncPreSnapshotReplyDeserialize2(const char* buf, uint32_t len) {
-  uint32_t              bytes = *((uint32_t*)buf);
-  SyncPreSnapshotReply* pMsg = taosMemoryMalloc(bytes);
-  ASSERT(pMsg != NULL);
-  syncPreSnapshotReplyDeserialize(buf, len, pMsg);
-  ASSERT(len == pMsg->bytes);
-  return pMsg;
-}
-
-void syncPreSnapshotReply2RpcMsg(const SyncPreSnapshotReply* pMsg, SRpcMsg* pRpcMsg) {
-  memset(pRpcMsg, 0, sizeof(*pRpcMsg));
-  pRpcMsg->msgType = pMsg->msgType;
-  pRpcMsg->contLen = pMsg->bytes;
-  pRpcMsg->pCont = rpcMallocCont(pRpcMsg->contLen);
-  syncPreSnapshotReplySerialize(pMsg, pRpcMsg->pCont, pRpcMsg->contLen);
-}
-
-void syncPreSnapshotReplyFromRpcMsg(const SRpcMsg* pRpcMsg, SyncPreSnapshotReply* pMsg) {
-  syncPreSnapshotReplyDeserialize(pRpcMsg->pCont, pRpcMsg->contLen, pMsg);
-}
-
-SyncPreSnapshotReply* syncPreSnapshotReplyFromRpcMsg2(const SRpcMsg* pRpcMsg) {
-  SyncPreSnapshotReply* pMsg = syncPreSnapshotReplyDeserialize2(pRpcMsg->pCont, pRpcMsg->contLen);
-  ASSERT(pMsg != NULL);
-  return pMsg;
-}
-
-cJSON* syncPreSnapshotReply2Json(const SyncPreSnapshotReply* pMsg) {
-  char   u64buf[128] = {0};
-  cJSON* pRoot = cJSON_CreateObject();
-
-  if (pMsg != NULL) {
-    cJSON_AddNumberToObject(pRoot, "bytes", pMsg->bytes);
-    cJSON_AddNumberToObject(pRoot, "vgId", pMsg->vgId);
-    cJSON_AddNumberToObject(pRoot, "msgType", pMsg->msgType);
-
-    cJSON* pSrcId = cJSON_CreateObject();
-    snprintf(u64buf, sizeof(u64buf), "%" PRIu64, pMsg->srcId.addr);
-    cJSON_AddStringToObject(pSrcId, "addr", u64buf);
-    {
-      uint64_t u64 = pMsg->srcId.addr;
-      cJSON*   pTmp = pSrcId;
-      char     host[128] = {0};
-      uint16_t port;
-      syncUtilU642Addr(u64, host, sizeof(host), &port);
-      cJSON_AddStringToObject(pTmp, "addr_host", host);
-      cJSON_AddNumberToObject(pTmp, "addr_port", port);
-    }
-    cJSON_AddNumberToObject(pSrcId, "vgId", pMsg->srcId.vgId);
-    cJSON_AddItemToObject(pRoot, "srcId", pSrcId);
-
-    cJSON* pDestId = cJSON_CreateObject();
-    snprintf(u64buf, sizeof(u64buf), "%" PRIu64, pMsg->destId.addr);
-    cJSON_AddStringToObject(pDestId, "addr", u64buf);
-    {
-      uint64_t u64 = pMsg->destId.addr;
-      cJSON*   pTmp = pDestId;
-      char     host[128] = {0};
-      uint16_t port;
-      syncUtilU642Addr(u64, host, sizeof(host), &port);
-      cJSON_AddStringToObject(pTmp, "addr_host", host);
-      cJSON_AddNumberToObject(pTmp, "addr_port", port);
-    }
-    cJSON_AddNumberToObject(pDestId, "vgId", pMsg->destId.vgId);
-    cJSON_AddItemToObject(pRoot, "destId", pDestId);
-
-    snprintf(u64buf, sizeof(u64buf), "%" PRIu64, pMsg->term);
-    cJSON_AddStringToObject(pRoot, "term", u64buf);
-
-    snprintf(u64buf, sizeof(u64buf), "%" PRId64, pMsg->snapStart);
-    cJSON_AddStringToObject(pRoot, "snap-start", u64buf);
+  pMsg->contLen = bytes;
+  if (pMsg->pCont == NULL) {
+    terrno = TSDB_CODE_OUT_OF_MEMORY;
+    return -1;
   }
 
-  cJSON* pJson = cJSON_CreateObject();
-  cJSON_AddItemToObject(pJson, "SyncPreSnapshotReply", pRoot);
-  return pJson;
-}
-
-char* syncPreSnapshotReply2Str(const SyncPreSnapshotReply* pMsg) {
-  cJSON* pJson = syncPreSnapshotReply2Json(pMsg);
-  char*  serialized = cJSON_Print(pJson);
-  cJSON_Delete(pJson);
-  return serialized;
-}
-
-void syncPreSnapshotReplyPrint(const SyncPreSnapshotReply* pMsg) {
-  char* serialized = syncPreSnapshotReply2Str(pMsg);
-  printf("syncPreSnapshotReplyPrint | len:%d | %s \n", (int32_t)strlen(serialized), serialized);
-  fflush(NULL);
-  taosMemoryFree(serialized);
-}
-
-void syncPreSnapshotReplyPrint2(char* s, const SyncPreSnapshotReply* pMsg) {
-  char* serialized = syncPreSnapshotReply2Str(pMsg);
-  printf("syncPreSnapshotReplyPrint2 | len:%d | %s | %s \n", (int32_t)strlen(serialized), s, serialized);
-  fflush(NULL);
-  taosMemoryFree(serialized);
-}
-
-void syncPreSnapshotReplyLog(const SyncPreSnapshotReply* pMsg) {
-  char* serialized = syncPreSnapshotReply2Str(pMsg);
-  sTrace("syncPreSnapshotReplyLog | len:%d | %s", (int32_t)strlen(serialized), serialized);
-  taosMemoryFree(serialized);
-}
-
-void syncPreSnapshotReplyLog2(char* s, const SyncPreSnapshotReply* pMsg) {
-  if (gRaftDetailLog) {
-    char* serialized = syncPreSnapshotReply2Str(pMsg);
-    sTrace("syncPreSnapshotReplyLog2 | len:%d | %s | %s", (int32_t)strlen(serialized), s, serialized);
-    taosMemoryFree(serialized);
-  }
+  SyncPreSnapshotReply* pPreSnapshotReply = pMsg->pCont;
+  pPreSnapshotReply->bytes = bytes;
+  pPreSnapshotReply->msgType = TDMT_SYNC_PRE_SNAPSHOT_REPLY;
+  pPreSnapshotReply->vgId = vgId;
+  return 0;
 }
 
 // ---- message process SyncApplyMsg----
diff --git a/source/libs/sync/src/syncSnapshot.c b/source/libs/sync/src/syncSnapshot.c
index 41dc3d3c395b09c96a33ea35f109153ae3a5247d..256be35f052d73f8a61628337353095778c3dd66 100644
--- a/source/libs/sync/src/syncSnapshot.c
+++ b/source/libs/sync/src/syncSnapshot.c
@@ -903,60 +903,3 @@ int32_t syncNodeOnSnapshotReply(SSyncNode *pSyncNode, SyncSnapshotRsp *pMsg) {
 
   return 0;
 }
-
-int32_t syncNodeOnPreSnapshot(SSyncNode *ths, SyncPreSnapshot *pMsg) {
-  syncLogRecvSyncPreSnapshot(ths, pMsg, "");
-
-  SyncPreSnapshotReply *pMsgReply = syncPreSnapshotReplyBuild(ths->vgId);
-  pMsgReply->srcId = ths->myRaftId;
-  pMsgReply->destId = pMsg->srcId;
-  pMsgReply->term = ths->pRaftStore->currentTerm;
-
-  SSyncLogStoreData *pData = ths->pLogStore->data;
-  SWal              *pWal = pData->pWal;
-
-  if (syncNodeIsMnode(ths)) {
-    pMsgReply->snapStart = SYNC_INDEX_BEGIN;
-
-  } else {
-    bool    isEmpty = ths->pLogStore->syncLogIsEmpty(ths->pLogStore);
-    int64_t walCommitVer = walGetCommittedVer(pWal);
-
-    if (!isEmpty && ths->commitIndex != walCommitVer) {
-      sNError(ths, "commit not same, wal-commit:%" PRId64 ", commit:%" PRId64 ", ignore", walCommitVer,
-              ths->commitIndex);
-      goto _IGNORE;
-    }
-
-    pMsgReply->snapStart = ths->commitIndex + 1;
-
-    // make local log clean
-    int32_t code = ths->pLogStore->syncLogTruncate(ths->pLogStore, pMsgReply->snapStart);
-    if (code != 0) {
-      sNError(ths, "truncate wal error");
-      goto _IGNORE;
-    }
-  }
-
-  // can not write behind _RESPONSE
-  SRpcMsg rpcMsg;
-
-_RESPONSE:
-  syncPreSnapshotReply2RpcMsg(pMsgReply, &rpcMsg);
-  syncNodeSendMsgById(&pMsgReply->destId, ths, &rpcMsg);
-
-  syncPreSnapshotReplyDestroy(pMsgReply);
-  return 0;
-
-_IGNORE:
-  syncPreSnapshotReplyDestroy(pMsgReply);
-  return 0;
-}
-
-int32_t syncNodeOnPreSnapshotReply(SSyncNode *ths, SyncPreSnapshotReply *pMsg) {
-  syncLogRecvSyncPreSnapshotReply(ths, pMsg, "");
-
-  // start snapshot
-
-  return 0;
-}
\ No newline at end of file
diff --git a/source/libs/sync/test/sync_test_lib/inc/syncTest.h b/source/libs/sync/test/sync_test_lib/inc/syncTest.h
index f853e7c823081317add6021056ab63a93a657ba3..0df4c69d64c9f9c8da498b1a06c8d4a771b0d799 100644
--- a/source/libs/sync/test/sync_test_lib/inc/syncTest.h
+++ b/source/libs/sync/test/sync_test_lib/inc/syncTest.h
@@ -349,6 +349,46 @@ void syncHeartbeatReplyPrint2(char* s, const SyncHeartbeatReply* pMsg);
 void syncHeartbeatReplyLog(const SyncHeartbeatReply* pMsg);
 void syncHeartbeatReplyLog2(char* s, const SyncHeartbeatReply* pMsg);
 
+SyncPreSnapshot* syncPreSnapshotBuild(int32_t vgId);
+void             syncPreSnapshotDestroy(SyncPreSnapshot* pMsg);
+void             syncPreSnapshotSerialize(const SyncPreSnapshot* pMsg, char* buf, uint32_t bufLen);
+void             syncPreSnapshotDeserialize(const char* buf, uint32_t len, SyncPreSnapshot* pMsg);
+char*            syncPreSnapshotSerialize2(const SyncPreSnapshot* pMsg, uint32_t* len);
+SyncPreSnapshot* syncPreSnapshotDeserialize2(const char* buf, uint32_t len);
+void             syncPreSnapshot2RpcMsg(const SyncPreSnapshot* pMsg, SRpcMsg* pRpcMsg);
+void             syncPreSnapshotFromRpcMsg(const SRpcMsg* pRpcMsg, SyncPreSnapshot* pMsg);
+SyncPreSnapshot* syncPreSnapshotFromRpcMsg2(const SRpcMsg* pRpcMsg);
+cJSON*           syncPreSnapshot2Json(const SyncPreSnapshot* pMsg);
+char*            syncPreSnapshot2Str(const SyncPreSnapshot* pMsg);
+
+// for debug ----------------------
+void syncPreSnapshotPrint(const SyncPreSnapshot* pMsg);
+void syncPreSnapshotPrint2(char* s, const SyncPreSnapshot* pMsg);
+void syncPreSnapshotLog(const SyncPreSnapshot* pMsg);
+void syncPreSnapshotLog2(char* s, const SyncPreSnapshot* pMsg);
+
+SyncPreSnapshotReply* syncPreSnapshotReplyBuild(int32_t vgId);
+void                  syncPreSnapshotReplyDestroy(SyncPreSnapshotReply* pMsg);
+void                  syncPreSnapshotReplySerialize(const SyncPreSnapshotReply* pMsg, char* buf, uint32_t bufLen);
+void                  syncPreSnapshotReplyDeserialize(const char* buf, uint32_t len, SyncPreSnapshotReply* pMsg);
+char*                 syncPreSnapshotReplySerialize2(const SyncPreSnapshotReply* pMsg, uint32_t* len);
+SyncPreSnapshotReply* syncPreSnapshotReplyDeserialize2(const char* buf, uint32_t len);
+void                  syncPreSnapshotReply2RpcMsg(const SyncPreSnapshotReply* pMsg, SRpcMsg* pRpcMsg);
+void                  syncPreSnapshotReplyFromRpcMsg(const SRpcMsg* pRpcMsg, SyncPreSnapshotReply* pMsg);
+SyncPreSnapshotReply* syncPreSnapshotReplyFromRpcMsg2(const SRpcMsg* pRpcMsg);
+cJSON*                syncPreSnapshotReply2Json(const SyncPreSnapshotReply* pMsg);
+char*                 syncPreSnapshotReply2Str(const SyncPreSnapshotReply* pMsg);
+
+// for debug ----------------------
+void syncPreSnapshotReplyPrint(const SyncPreSnapshotReply* pMsg);
+void syncPreSnapshotReplyPrint2(char* s, const SyncPreSnapshotReply* pMsg);
+void syncPreSnapshotReplyLog(const SyncPreSnapshotReply* pMsg);
+void syncPreSnapshotReplyLog2(char* s, const SyncPreSnapshotReply* pMsg);
+
+// ---------------------------------------------
+int32_t syncNodeOnPreSnapshot(SSyncNode* ths, SyncPreSnapshot* pMsg);
+int32_t syncNodeOnPreSnapshotReply(SSyncNode* ths, SyncPreSnapshotReply* pMsg);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/source/libs/sync/test/sync_test_lib/src/syncMessageDebug.c b/source/libs/sync/test/sync_test_lib/src/syncMessageDebug.c
index fe4f78976fa8a68195e55fc1bc1c22450b365810..d1125c66d93835e52d91cc40f0fcd1a88c204adc 100644
--- a/source/libs/sync/test/sync_test_lib/src/syncMessageDebug.c
+++ b/source/libs/sync/test/sync_test_lib/src/syncMessageDebug.c
@@ -1942,3 +1942,300 @@ void syncHeartbeatReplyLog2(char* s, const SyncHeartbeatReply* pMsg) {
     taosMemoryFree(serialized);
   }
 }
+
+// ---- message process SyncPreSnapshot----
+SyncPreSnapshot* syncPreSnapshotBuild(int32_t vgId) {
+  uint32_t         bytes = sizeof(SyncPreSnapshot);
+  SyncPreSnapshot* pMsg = taosMemoryMalloc(bytes);
+  memset(pMsg, 0, bytes);
+  pMsg->bytes = bytes;
+  pMsg->vgId = vgId;
+  pMsg->msgType = TDMT_SYNC_PRE_SNAPSHOT;
+  return pMsg;
+}
+
+void syncPreSnapshotDestroy(SyncPreSnapshot* pMsg) {
+  if (pMsg != NULL) {
+    taosMemoryFree(pMsg);
+  }
+}
+
+void syncPreSnapshotSerialize(const SyncPreSnapshot* pMsg, char* buf, uint32_t bufLen) {
+  ASSERT(pMsg->bytes <= bufLen);
+  memcpy(buf, pMsg, pMsg->bytes);
+}
+
+void syncPreSnapshotDeserialize(const char* buf, uint32_t len, SyncPreSnapshot* pMsg) {
+  memcpy(pMsg, buf, len);
+  ASSERT(len == pMsg->bytes);
+}
+
+char* syncPreSnapshotSerialize2(const SyncPreSnapshot* pMsg, uint32_t* len) {
+  char* buf = taosMemoryMalloc(pMsg->bytes);
+  ASSERT(buf != NULL);
+  syncPreSnapshotSerialize(pMsg, buf, pMsg->bytes);
+  if (len != NULL) {
+    *len = pMsg->bytes;
+  }
+  return buf;
+}
+
+SyncPreSnapshot* syncPreSnapshotDeserialize2(const char* buf, uint32_t len) {
+  uint32_t         bytes = *((uint32_t*)buf);
+  SyncPreSnapshot* pMsg = taosMemoryMalloc(bytes);
+  ASSERT(pMsg != NULL);
+  syncPreSnapshotDeserialize(buf, len, pMsg);
+  ASSERT(len == pMsg->bytes);
+  return pMsg;
+}
+
+void syncPreSnapshot2RpcMsg(const SyncPreSnapshot* pMsg, SRpcMsg* pRpcMsg) {
+  memset(pRpcMsg, 0, sizeof(*pRpcMsg));
+  pRpcMsg->msgType = pMsg->msgType;
+  pRpcMsg->contLen = pMsg->bytes;
+  pRpcMsg->pCont = rpcMallocCont(pRpcMsg->contLen);
+  syncPreSnapshotSerialize(pMsg, pRpcMsg->pCont, pRpcMsg->contLen);
+}
+
+void syncPreSnapshotFromRpcMsg(const SRpcMsg* pRpcMsg, SyncPreSnapshot* pMsg) {
+  syncPreSnapshotDeserialize(pRpcMsg->pCont, pRpcMsg->contLen, pMsg);
+}
+
+SyncPreSnapshot* syncPreSnapshotFromRpcMsg2(const SRpcMsg* pRpcMsg) {
+  SyncPreSnapshot* pMsg = syncPreSnapshotDeserialize2(pRpcMsg->pCont, pRpcMsg->contLen);
+  ASSERT(pMsg != NULL);
+  return pMsg;
+}
+
+cJSON* syncPreSnapshot2Json(const SyncPreSnapshot* pMsg) {
+  char   u64buf[128] = {0};
+  cJSON* pRoot = cJSON_CreateObject();
+
+  if (pMsg != NULL) {
+    cJSON_AddNumberToObject(pRoot, "bytes", pMsg->bytes);
+    cJSON_AddNumberToObject(pRoot, "vgId", pMsg->vgId);
+    cJSON_AddNumberToObject(pRoot, "msgType", pMsg->msgType);
+
+    cJSON* pSrcId = cJSON_CreateObject();
+    snprintf(u64buf, sizeof(u64buf), "%" PRIu64, pMsg->srcId.addr);
+    cJSON_AddStringToObject(pSrcId, "addr", u64buf);
+    {
+      uint64_t u64 = pMsg->srcId.addr;
+      cJSON*   pTmp = pSrcId;
+      char     host[128] = {0};
+      uint16_t port;
+      syncUtilU642Addr(u64, host, sizeof(host), &port);
+      cJSON_AddStringToObject(pTmp, "addr_host", host);
+      cJSON_AddNumberToObject(pTmp, "addr_port", port);
+    }
+    cJSON_AddNumberToObject(pSrcId, "vgId", pMsg->srcId.vgId);
+    cJSON_AddItemToObject(pRoot, "srcId", pSrcId);
+
+    cJSON* pDestId = cJSON_CreateObject();
+    snprintf(u64buf, sizeof(u64buf), "%" PRIu64, pMsg->destId.addr);
+    cJSON_AddStringToObject(pDestId, "addr", u64buf);
+    {
+      uint64_t u64 = pMsg->destId.addr;
+      cJSON*   pTmp = pDestId;
+      char     host[128] = {0};
+      uint16_t port;
+      syncUtilU642Addr(u64, host, sizeof(host), &port);
+      cJSON_AddStringToObject(pTmp, "addr_host", host);
+      cJSON_AddNumberToObject(pTmp, "addr_port", port);
+    }
+    cJSON_AddNumberToObject(pDestId, "vgId", pMsg->destId.vgId);
+    cJSON_AddItemToObject(pRoot, "destId", pDestId);
+
+    snprintf(u64buf, sizeof(u64buf), "%" PRIu64, pMsg->term);
+    cJSON_AddStringToObject(pRoot, "term", u64buf);
+  }
+
+  cJSON* pJson = cJSON_CreateObject();
+  cJSON_AddItemToObject(pJson, "SyncPreSnapshot", pRoot);
+  return pJson;
+}
+
+char* syncPreSnapshot2Str(const SyncPreSnapshot* pMsg) {
+  cJSON* pJson = syncPreSnapshot2Json(pMsg);
+  char*  serialized = cJSON_Print(pJson);
+  cJSON_Delete(pJson);
+  return serialized;
+}
+
+void syncPreSnapshotPrint(const SyncPreSnapshot* pMsg) {
+  char* serialized = syncPreSnapshot2Str(pMsg);
+  printf("syncPreSnapshotPrint | len:%d | %s \n", (int32_t)strlen(serialized), serialized);
+  fflush(NULL);
+  taosMemoryFree(serialized);
+}
+
+void syncPreSnapshotPrint2(char* s, const SyncPreSnapshot* pMsg) {
+  char* serialized = syncPreSnapshot2Str(pMsg);
+  printf("syncPreSnapshotPrint2 | len:%d | %s | %s \n", (int32_t)strlen(serialized), s, serialized);
+  fflush(NULL);
+  taosMemoryFree(serialized);
+}
+
+void syncPreSnapshotLog(const SyncPreSnapshot* pMsg) {
+  char* serialized = syncPreSnapshot2Str(pMsg);
+  sTrace("syncPreSnapshotLog | len:%d | %s", (int32_t)strlen(serialized), serialized);
+  taosMemoryFree(serialized);
+}
+
+void syncPreSnapshotLog2(char* s, const SyncPreSnapshot* pMsg) {
+  if (gRaftDetailLog) {
+    char* serialized = syncPreSnapshot2Str(pMsg);
+    sTrace("syncPreSnapshotLog2 | len:%d | %s | %s", (int32_t)strlen(serialized), s, serialized);
+    taosMemoryFree(serialized);
+  }
+}
+
+// ---- message process SyncPreSnapshotReply----
+SyncPreSnapshotReply* syncPreSnapshotReplyBuild(int32_t vgId) {
+  uint32_t              bytes = sizeof(SyncPreSnapshotReply);
+  SyncPreSnapshotReply* pMsg = taosMemoryMalloc(bytes);
+  memset(pMsg, 0, bytes);
+  pMsg->bytes = bytes;
+  pMsg->vgId = vgId;
+  pMsg->msgType = TDMT_SYNC_PRE_SNAPSHOT_REPLY;
+  return pMsg;
+}
+
+void syncPreSnapshotReplyDestroy(SyncPreSnapshotReply* pMsg) {
+  if (pMsg != NULL) {
+    taosMemoryFree(pMsg);
+  }
+}
+
+void syncPreSnapshotReplySerialize(const SyncPreSnapshotReply* pMsg, char* buf, uint32_t bufLen) {
+  ASSERT(pMsg->bytes <= bufLen);
+  memcpy(buf, pMsg, pMsg->bytes);
+}
+
+void syncPreSnapshotReplyDeserialize(const char* buf, uint32_t len, SyncPreSnapshotReply* pMsg) {
+  memcpy(pMsg, buf, len);
+  ASSERT(len == pMsg->bytes);
+}
+
+char* syncPreSnapshotReplySerialize2(const SyncPreSnapshotReply* pMsg, uint32_t* len) {
+  char* buf = taosMemoryMalloc(pMsg->bytes);
+  ASSERT(buf != NULL);
+  syncPreSnapshotReplySerialize(pMsg, buf, pMsg->bytes);
+  if (len != NULL) {
+    *len = pMsg->bytes;
+  }
+  return buf;
+}
+
+SyncPreSnapshotReply* syncPreSnapshotReplyDeserialize2(const char* buf, uint32_t len) {
+  uint32_t              bytes = *((uint32_t*)buf);
+  SyncPreSnapshotReply* pMsg = taosMemoryMalloc(bytes);
+  ASSERT(pMsg != NULL);
+  syncPreSnapshotReplyDeserialize(buf, len, pMsg);
+  ASSERT(len == pMsg->bytes);
+  return pMsg;
+}
+
+void syncPreSnapshotReply2RpcMsg(const SyncPreSnapshotReply* pMsg, SRpcMsg* pRpcMsg) {
+  memset(pRpcMsg, 0, sizeof(*pRpcMsg));
+  pRpcMsg->msgType = pMsg->msgType;
+  pRpcMsg->contLen = pMsg->bytes;
+  pRpcMsg->pCont = rpcMallocCont(pRpcMsg->contLen);
+  syncPreSnapshotReplySerialize(pMsg, pRpcMsg->pCont, pRpcMsg->contLen);
+}
+
+void syncPreSnapshotReplyFromRpcMsg(const SRpcMsg* pRpcMsg, SyncPreSnapshotReply* pMsg) {
+  syncPreSnapshotReplyDeserialize(pRpcMsg->pCont, pRpcMsg->contLen, pMsg);
+}
+
+SyncPreSnapshotReply* syncPreSnapshotReplyFromRpcMsg2(const SRpcMsg* pRpcMsg) {
+  SyncPreSnapshotReply* pMsg = syncPreSnapshotReplyDeserialize2(pRpcMsg->pCont, pRpcMsg->contLen);
+  ASSERT(pMsg != NULL);
+  return pMsg;
+}
+
+cJSON* syncPreSnapshotReply2Json(const SyncPreSnapshotReply* pMsg) {
+  char   u64buf[128] = {0};
+  cJSON* pRoot = cJSON_CreateObject();
+
+  if (pMsg != NULL) {
+    cJSON_AddNumberToObject(pRoot, "bytes", pMsg->bytes);
+    cJSON_AddNumberToObject(pRoot, "vgId", pMsg->vgId);
+    cJSON_AddNumberToObject(pRoot, "msgType", pMsg->msgType);
+
+    cJSON* pSrcId = cJSON_CreateObject();
+    snprintf(u64buf, sizeof(u64buf), "%" PRIu64, pMsg->srcId.addr);
+    cJSON_AddStringToObject(pSrcId, "addr", u64buf);
+    {
+      uint64_t u64 = pMsg->srcId.addr;
+      cJSON*   pTmp = pSrcId;
+      char     host[128] = {0};
+      uint16_t port;
+      syncUtilU642Addr(u64, host, sizeof(host), &port);
+      cJSON_AddStringToObject(pTmp, "addr_host", host);
+      cJSON_AddNumberToObject(pTmp, "addr_port", port);
+    }
+    cJSON_AddNumberToObject(pSrcId, "vgId", pMsg->srcId.vgId);
+    cJSON_AddItemToObject(pRoot, "srcId", pSrcId);
+
+    cJSON* pDestId = cJSON_CreateObject();
+    snprintf(u64buf, sizeof(u64buf), "%" PRIu64, pMsg->destId.addr);
+    cJSON_AddStringToObject(pDestId, "addr", u64buf);
+    {
+      uint64_t u64 = pMsg->destId.addr;
+      cJSON*   pTmp = pDestId;
+      char     host[128] = {0};
+      uint16_t port;
+      syncUtilU642Addr(u64, host, sizeof(host), &port);
+      cJSON_AddStringToObject(pTmp, "addr_host", host);
+      cJSON_AddNumberToObject(pTmp, "addr_port", port);
+    }
+    cJSON_AddNumberToObject(pDestId, "vgId", pMsg->destId.vgId);
+    cJSON_AddItemToObject(pRoot, "destId", pDestId);
+
+    snprintf(u64buf, sizeof(u64buf), "%" PRIu64, pMsg->term);
+    cJSON_AddStringToObject(pRoot, "term", u64buf);
+
+    snprintf(u64buf, sizeof(u64buf), "%" PRId64, pMsg->snapStart);
+    cJSON_AddStringToObject(pRoot, "snap-start", u64buf);
+  }
+
+  cJSON* pJson = cJSON_CreateObject();
+  cJSON_AddItemToObject(pJson, "SyncPreSnapshotReply", pRoot);
+  return pJson;
+}
+
+char* syncPreSnapshotReply2Str(const SyncPreSnapshotReply* pMsg) {
+  cJSON* pJson = syncPreSnapshotReply2Json(pMsg);
+  char*  serialized = cJSON_Print(pJson);
+  cJSON_Delete(pJson);
+  return serialized;
+}
+
+void syncPreSnapshotReplyPrint(const SyncPreSnapshotReply* pMsg) {
+  char* serialized = syncPreSnapshotReply2Str(pMsg);
+  printf("syncPreSnapshotReplyPrint | len:%d | %s \n", (int32_t)strlen(serialized), serialized);
+  fflush(NULL);
+  taosMemoryFree(serialized);
+}
+
+void syncPreSnapshotReplyPrint2(char* s, const SyncPreSnapshotReply* pMsg) {
+  char* serialized = syncPreSnapshotReply2Str(pMsg);
+  printf("syncPreSnapshotReplyPrint2 | len:%d | %s | %s \n", (int32_t)strlen(serialized), s, serialized);
+  fflush(NULL);
+  taosMemoryFree(serialized);
+}
+
+void syncPreSnapshotReplyLog(const SyncPreSnapshotReply* pMsg) {
+  char* serialized = syncPreSnapshotReply2Str(pMsg);
+  sTrace("syncPreSnapshotReplyLog | len:%d | %s", (int32_t)strlen(serialized), serialized);
+  taosMemoryFree(serialized);
+}
+
+void syncPreSnapshotReplyLog2(char* s, const SyncPreSnapshotReply* pMsg) {
+  if (gRaftDetailLog) {
+    char* serialized = syncPreSnapshotReply2Str(pMsg);
+    sTrace("syncPreSnapshotReplyLog2 | len:%d | %s | %s", (int32_t)strlen(serialized), s, serialized);
+    taosMemoryFree(serialized);
+  }
+}
diff --git a/source/libs/sync/test/sync_test_lib/src/syncSnapshotDebug.c b/source/libs/sync/test/sync_test_lib/src/syncSnapshotDebug.c
index fdaf4b8b341ccc61b645eabeb433e57a11617556..82e23b2885b752712aa0ef5a6740f5149a0118b1 100644
--- a/source/libs/sync/test/sync_test_lib/src/syncSnapshotDebug.c
+++ b/source/libs/sync/test/sync_test_lib/src/syncSnapshotDebug.c
@@ -130,3 +130,60 @@ char *snapshotReceiver2Str(SSyncSnapshotReceiver *pReceiver) {
   cJSON_Delete(pJson);
   return serialized;
 }
+
+int32_t syncNodeOnPreSnapshot(SSyncNode *ths, SyncPreSnapshot *pMsg) {
+  syncLogRecvSyncPreSnapshot(ths, pMsg, "");
+
+  SyncPreSnapshotReply *pMsgReply = syncPreSnapshotReplyBuild(ths->vgId);
+  pMsgReply->srcId = ths->myRaftId;
+  pMsgReply->destId = pMsg->srcId;
+  pMsgReply->term = ths->pRaftStore->currentTerm;
+
+  SSyncLogStoreData *pData = ths->pLogStore->data;
+  SWal              *pWal = pData->pWal;
+
+  if (syncNodeIsMnode(ths)) {
+    pMsgReply->snapStart = SYNC_INDEX_BEGIN;
+
+  } else {
+    bool    isEmpty = ths->pLogStore->syncLogIsEmpty(ths->pLogStore);
+    int64_t walCommitVer = walGetCommittedVer(pWal);
+
+    if (!isEmpty && ths->commitIndex != walCommitVer) {
+      sNError(ths, "commit not same, wal-commit:%" PRId64 ", commit:%" PRId64 ", ignore", walCommitVer,
+              ths->commitIndex);
+      goto _IGNORE;
+    }
+
+    pMsgReply->snapStart = ths->commitIndex + 1;
+
+    // make local log clean
+    int32_t code = ths->pLogStore->syncLogTruncate(ths->pLogStore, pMsgReply->snapStart);
+    if (code != 0) {
+      sNError(ths, "truncate wal error");
+      goto _IGNORE;
+    }
+  }
+
+  // can not write behind _RESPONSE
+  SRpcMsg rpcMsg;
+
+_RESPONSE:
+  syncPreSnapshotReply2RpcMsg(pMsgReply, &rpcMsg);
+  syncNodeSendMsgById(&pMsgReply->destId, ths, &rpcMsg);
+
+  syncPreSnapshotReplyDestroy(pMsgReply);
+  return 0;
+
+_IGNORE:
+  syncPreSnapshotReplyDestroy(pMsgReply);
+  return 0;
+}
+
+int32_t syncNodeOnPreSnapshotReply(SSyncNode *ths, SyncPreSnapshotReply *pMsg) {
+  syncLogRecvSyncPreSnapshotReply(ths, pMsg, "");
+
+  // start snapshot
+
+  return 0;
+}
\ No newline at end of file