session: add check resource group hint existence (#45296) (#45347)

close #45178

session/session.go

@@ -2184,18 +2184,28 @@ func (s *session) ExecuteStmt(ctx context.Context, stmtNode ast.StmtNode) (sqlex
 	s.setRequestSource(ctx, stmtLabel, stmtNode)
 
 	// Backup the original resource group name since sql hint might change it during optimization
-	originalResourceGroup := s.GetSessionVars().ResourceGroupName
+	originalResourceGroup := sessVars.ResourceGroupName
 
 	// Transform abstract syntax tree to a physical plan(stored in executor.ExecStmt).
 	compiler := executor.Compiler{Ctx: s}
 	stmt, err := compiler.Compile(ctx, stmtNode)
 	// session resource-group might be changed by query hint, ensure restore it back when
 	// the execution finished.
-	if s.GetSessionVars().ResourceGroupName != originalResourceGroup {
-		defer func() {
-			// Restore the resource group for the session
-			s.GetSessionVars().ResourceGroupName = originalResourceGroup
-		}()
+	if sessVars.ResourceGroupName != originalResourceGroup {
+		// if target resource group doesn't exist, fallback to the origin resource group.
+		if _, ok := domain.GetDomain(s).InfoSchema().ResourceGroupByName(model.NewCIStr(sessVars.ResourceGroupName)); !ok {
+			logutil.Logger(ctx).Warn("Unknown resource group from hint", zap.String("name", sessVars.ResourceGroupName))
+			sessVars.ResourceGroupName = originalResourceGroup
+			// if we are in a txn, should also reset the txn resource group.
+			if txn, err := s.Txn(false); err == nil && txn != nil && txn.Valid() {
+				txn.SetOption(kv.ResourceGroupName, originalResourceGroup)
+			}
+		} else {
+			defer func() {
+				// Restore the resource group for the session
+				sessVars.ResourceGroupName = originalResourceGroup
+			}()
+		}
 	}
 	if err != nil {
 		s.rollbackOnError(ctx)