EntityFramework中使用Include可能带来的问题

这个问题是在处理层级查询上出现的，按照以前的经验当查询A以及A的子集合B[]的时候join一下比分两次查询快，但是当子集合比较多等原因的时候时间不是线性增长而是指数，原因应该是重复数据带来的效率负载增加，比如第一种我的单元测试时间Duration在4-6左右，当增加到3个子集合的时候就在14-22之间了，而Ef中的做法是把每个join结果unicon 起来，看着那么大串的数据不慢才怪，还是乖乖分开了。

 时间如图：

 

测试代码：

    public class ModelTesting
    {
        private EFContext _dbContext;
        public ModelTesting()
        {
            string cnn = System.Configuration.ConfigurationManager.ConnectionStrings[0].ConnectionString;

            _dbContext = new EFContext(cnn);
            
        }
        [Fact]
        public void Test()
        {
            var key = 1000;
            var uid = new Guid("3905858E-A32E-DF11-BA8F-001CF0CD104B");
            var myResume = _dbContext.Set<MyUser>()
                .Single(u => u.UserId == uid);
            myResume.Works.ToList();
            myResume.Resumes.ToList();
            myResume.Projects.ToList();
            myResume.Jobs.ToList();
            myResume=_dbContext.Set<MyUser>()
                .Include("Resumes")
                .Include("Jobs")
                .Include("Projects")
                .Include("Works")
                .Single(u => u.UserId == uid);

        }
    }

    public class EFContext:DbContext
    {
        public EFContext(string cnn):base(cnn)
        {
            this.Configuration.LazyLoadingEnabled = true;
        }

        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            base.OnModelCreating(modelBuilder);
            modelBuilder.Entity<MyResume>();
            modelBuilder.Entity<MyWorkExper>();
            modelBuilder.Entity<MyProject>();
            modelBuilder.Entity<MyUser>();
        }
    }
    [Table("Resume", Schema = "dbo")]
    public class MyResume
    {
        [Key]
        public int Key { get; set; }
        [ForeignKey("Owner")]
        public Guid UserId { get; set; }
        public MyUser Owner { get; set; }
    }

    [Table("WorkExperience", Schema = "Resume")]
    public class MyWorkExper
    {
        [Key]
        public int WorkId { get; set; }
        [ForeignKey("Owner")]
        public Guid UserId { get; set; }
        public MyUser Owner { get; set; }
    }
        [Table("project",Schema = "Resume")]
    public class MyProject
        {
            [Key]
            public int ProjectId { get; set; }
            [ForeignKey("Owner")]
            public Guid UserId { get; set; }
            public MyUser Owner { get; set; }
        }
    [Table("EnterpriseUser", Schema = "Offer")]
    public  class MyUser
    {
        [Key]
        [Column("UserGuid")]
        public Guid UserId { get; set; }
        public virtual ICollection<MyResume> Resumes { get; set; }
        public virtual ICollection<MyProject> Projects { get; set; }
        public virtual ICollection<MyWorkExper> Works { get; set; }
        public virtual ICollection<MyJob> Jobs { get; set; }
    }
    [Table("Offer", Schema = "Offer")]
    public class MyJob
    {
        [Key]
        public long Key
        {
            get;
            set;
        }
        [ForeignKey("Owner")]
        [Required]
        public Guid UserID { get; set; }

        public virtual MyUser Owner { get; set; }
    }