code: func (e *ShowDDLJobQueriesExec) Open(ctx context.Context) error {
  	if err := e.baseExecutor.Open(ctx); err != nil {
  		return err
  	}
  	txn, err := e.ctx.Txn(true)
  	if err != nil {
  		return err
  	}
  	jobs, err := admin.GetDDLJobs(txn)
  	if err != nil {
  		return err
  	}
  	historyJobs, err := admin.GetHistoryDDLJobs(txn, admin.DefNumHistoryJobs)
  	if err != nil {
  		return err
  	}
  
  	e.jobs = append(e.jobs, jobs...)
  	e.jobs = append(e.jobs, historyJobs...)
  
  	return nil
  }
docs: // Open implements the Executor Open interface.