Merge pull request #18738 from taosdata/fix/TD-20857

enh: speed up drop dnode and avoid snapshot transfer

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

@@ -383,9 +383,9 @@ static int32_t mndProcessStatusReq(SRpcMsg *pReq) {
               pGid->syncCanRead != pVload->syncCanRead) {
             mInfo(
                 "vgId:%d, state changed by status msg, old state:%s restored:%d canRead:%d new state:%s restored:%d "
-                "canRead:%d",
+                "canRead:%d, dnode:%d",
                 pVgroup->vgId, syncStr(pGid->syncState), pGid->syncRestore, pGid->syncCanRead,
-                syncStr(pVload->syncState), pVload->syncRestore, pVload->syncCanRead);
+                syncStr(pVload->syncState), pVload->syncRestore, pVload->syncCanRead, pDnode->id);
             pGid->syncState = pVload->syncState;
             pGid->syncRestore = pVload->syncRestore;
             pGid->syncCanRead = pVload->syncCanRead;

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

@@ -1126,7 +1126,8 @@ int32_t mndSetMoveVgroupInfoToTrans(SMnode *pMnode, STrans *pTrans, SDbObj *pDb,
   }
 
   if (!force) {
-    mInfo("vgId:%d, will add 1 vnode", pVgroup->vgId);
+    if (newVg.replica == 1) {
+      mInfo("vgId:%d, will add 1 vnode, replca:1", pVgroup->vgId);
       if (mndAddVnodeToVgroup(pMnode, pTrans, &newVg, pArray) != 0) return -1;
       for (int32_t i = 0; i < newVg.replica - 1; ++i) {
         if (mndAddAlterVnodeReplicaAction(pMnode, pTrans, pDb, &newVg, newVg.vnodeGid[i].dnodeId) != 0) return -1;
@@ -1134,7 +1135,7 @@ int32_t mndSetMoveVgroupInfoToTrans(SMnode *pMnode, STrans *pTrans, SDbObj *pDb,
       if (mndAddCreateVnodeAction(pMnode, pTrans, pDb, &newVg, &newVg.vnodeGid[newVg.replica - 1]) != 0) return -1;
       if (mndAddAlterVnodeConfirmAction(pMnode, pTrans, pDb, &newVg) != 0) return -1;
 
-    mInfo("vgId:%d, will remove 1 vnode", pVgroup->vgId);
+      mInfo("vgId:%d, will remove 1 vnode, replca:2", pVgroup->vgId);
       newVg.replica--;
       SVnodeGid del = newVg.vnodeGid[vnIndex];
       newVg.vnodeGid[vnIndex] = newVg.vnodeGid[newVg.replica];
@@ -1154,6 +1155,32 @@ int32_t mndSetMoveVgroupInfoToTrans(SMnode *pMnode, STrans *pTrans, SDbObj *pDb,
         if (mndAddAlterVnodeReplicaAction(pMnode, pTrans, pDb, &newVg, newVg.vnodeGid[i].dnodeId) != 0) return -1;
       }
       if (mndAddAlterVnodeConfirmAction(pMnode, pTrans, pDb, &newVg) != 0) return -1;
+    } else {  // new replica == 3
+      mInfo("vgId:%d, will add 1 vnode, replca:3", pVgroup->vgId);
+      if (mndAddVnodeToVgroup(pMnode, pTrans, &newVg, pArray) != 0) return -1;
+      mInfo("vgId:%d, will remove 1 vnode, replca:4", pVgroup->vgId);
+      newVg.replica--;
+      SVnodeGid del = newVg.vnodeGid[vnIndex];
+      newVg.vnodeGid[vnIndex] = newVg.vnodeGid[newVg.replica];
+      memset(&newVg.vnodeGid[newVg.replica], 0, sizeof(SVnodeGid));
+      {
+        SSdbRaw *pRaw = mndVgroupActionEncode(&newVg);
+        if (pRaw == NULL) return -1;
+        if (mndTransAppendRedolog(pTrans, pRaw) != 0) {
+          sdbFreeRaw(pRaw);
+          return -1;
+        }
+        (void)sdbSetRawStatus(pRaw, SDB_STATUS_READY);
+      }
+
+      if (mndAddDropVnodeAction(pMnode, pTrans, pDb, &newVg, &del, true) != 0) return -1;
+      for (int32_t i = 0; i < newVg.replica; ++i) {
+        if (i == vnIndex) continue;
+        if (mndAddAlterVnodeReplicaAction(pMnode, pTrans, pDb, &newVg, newVg.vnodeGid[i].dnodeId) != 0) return -1;
+      }
+      if (mndAddCreateVnodeAction(pMnode, pTrans, pDb, &newVg, &newVg.vnodeGid[vnIndex]) != 0) return -1;
+      if (mndAddAlterVnodeConfirmAction(pMnode, pTrans, pDb, &newVg) != 0) return -1;
+    }
   } else {
     mInfo("vgId:%d, will add 1 vnode and force remove 1 vnode", pVgroup->vgId);
     if (mndAddVnodeToVgroup(pMnode, pTrans, &newVg, pArray) != 0) return -1;