fix: make vmProcessAlterHashRangeReq idempotent

source/dnode/mgmt/mgmt_vnode/src/vmHandle.c

@@ -484,10 +484,18 @@ int32_t vmProcessAlterHashRangeReq(SVnodeMgmt *pMgmt, SRpcMsg *pMsg) {
 
   int32_t srcVgId = req.srcVgId;
   int32_t dstVgId = req.dstVgId;
+
+  SVnodeObj *pVnode = vmAcquireVnode(pMgmt, dstVgId);
+  if (pVnode != NULL) {
+    dError("vgId:%d, vnode already exist", dstVgId);
+    vmReleaseVnode(pMgmt, pVnode);
+    terrno = TSDB_CODE_VND_ALREADY_EXIST;
+    return -1;
+  }
+
   dInfo("vgId:%d, start to alter vnode hashrange:[%u, %u], dstVgId:%d", req.srcVgId, req.hashBegin, req.hashEnd,
         req.dstVgId);
-
-  SVnodeObj *pVnode = vmAcquireVnode(pMgmt, srcVgId);
+  pVnode = vmAcquireVnode(pMgmt, srcVgId);
   if (pVnode == NULL) {
     dError("vgId:%d, failed to alter hashrange since %s", srcVgId, terrstr());
     terrno = TSDB_CODE_VND_NOT_EXIST;

source/dnode/mnode/impl/src/mndVgroup.c

@@ -1217,6 +1217,7 @@ static int32_t mndAddAlterVnodeHashRangeAction(SMnode *pMnode, STrans *pTrans, i
   action.pCont = pReq;
   action.contLen = contLen;
   action.msgType = TDMT_VND_ALTER_HASHRANGE;
+  action.acceptableCode = TSDB_CODE_VND_ALREADY_EXIST;
 
   if (mndTransAppendRedoAction(pTrans, &action) != 0) {
     taosMemoryFree(pReq);