/*

Suppose you have a list of 1,000,000 orders, 

please write code to get all canceled orders among them from oracle/mssql/postgresql (table has around 10 million orders).

*/

​

public class Order

{

   public string OrderId {get;set;}

   public bool Status {get;set;} //cancleled

}

​

public interface IOrderRepository {

    //1000 ids

    Task<IList<string>> GetOrdersAsync(IEnumerable<string> ids);

}

​

public class OrderService : IOrderService 

{

    public readonly IOrderRepository repository;

    //10000

    public async Task<IList<Order>> GetCanncelledOrdersAsync(IEnumerable<string> ids) //guids

    {

    }

}