C# 实体框架6异步方法与同步方法的性能_C#_Entity Framework_Asynchronous

C# 实体框架6异步方法与同步方法的性能

c# entity-framework asynchronous

C# 实体框架6异步方法与同步方法的性能,c#,entity-framework,asynchronous,C#,Entity Framework,Asynchronous,我修改了一个Github项目，以测试一些与实体框架相关的查询方式型号： [Table("Player")] public partial class Player { public int Id { get; set; } [Required] [StringLength(200)] public string FirstName { get; set; } [Required] [StringLength(200)] public

我修改了一个Github项目，以测试一些与实体框架相关的查询方式

型号：

[Table("Player")]
public partial class Player
{
    public int Id { get; set; }

    [Required]
    [StringLength(200)]
    public string FirstName { get; set; }

    [Required]
    [StringLength(200)]
    public string LastName { get; set; }

    public DateTime DateOfBirth { get; set; }

    public int TeamId { get; set; }

    public virtual Team Team { get; set; }
}

[Table("Team")]
public partial class Team
{
    public Team()
    {
        Players = new HashSet<Player>();
    }

    public int Id { get; set; }

    [Required]
    [StringLength(200)]
    public string Name { get; set; }

    public DateTime FoundingDate { get; set; }

    public int SportId { get; set; }

    public virtual ICollection<Player> Players { get; set; }

    public virtual Sport Sport { get; set; }
}

[Table("Sport")]
public partial class Sport
{
    public Sport()
    {
        Teams = new HashSet<Team>();
    }

    public int Id { get; set; }

    [StringLength(100)]
    public string Name { get; set; }

    public virtual ICollection<Team> Teams { get; set; }
}

EF“Async”-FirstOrDefaultAsync（）和ToListAsync（）

EF与Select into DTO对象“同步”

context.Players.Select(p => new PlayerDTO()
                {
                    Id = p.Id,
                    FirstName = p.FirstName,
                    DateOfBirth = p.DateOfBirth,
                    LastName = p.LastName,
                    TeamId = p.TeamId

                }).FirstOrDefault(x => x.Id == id);

context.Players.Where(x => x.TeamId == teamId).Select(p => new PlayerDTO()
                {
                    Id = p.Id,
                    FirstName = p.FirstName,
                    DateOfBirth = p.DateOfBirth,
                    LastName = p.LastName,
                    TeamId = p.TeamId
                }).ToList();

context.Teams.Where(x => x.SportId == sportId).Select(t => new TeamDTO()
                    {
                        Id = t.Id,
                        FoundingDate = t.FoundingDate,
                        Name = t.Name,
                        SportId = t.SportId,
                        Players = t.Players.Select(p => new PlayerDTO()
                        {
                            Id = p.Id,
                            FirstName = p.FirstName,
                            DateOfBirth = p.DateOfBirth,
                            LastName = p.LastName,
                            TeamId = p.TeamId
                        }).ToList()
                    }).ToList();

await context.Players.Select(p => new PlayerDTO()
                {
                    Id = p.Id,
                    FirstName = p.FirstName,
                    DateOfBirth = p.DateOfBirth,
                    LastName = p.LastName,
                    TeamId = p.TeamId

                }).FirstOrDefaultAsync(x => x.Id == id);

 await context.Players.Where(x => x.TeamId == teamId).Select(p => new PlayerDTO()
                {
                    Id = p.Id,
                    FirstName = p.FirstName,
                    DateOfBirth = p.DateOfBirth,
                    LastName = p.LastName,
                    TeamId = p.TeamId
                }).ToListAsync();

await context.Teams.Where(x => x.SportId == sportId).Select(t => new TeamDTO()
                {
                    Id = t.Id,
                    FoundingDate = t.FoundingDate,
                    Name = t.Name,
                    SportId = t.SportId,
                    Players = t.Players.Select(p => new PlayerDTO()
                    {
                        Id = p.Id,
                        FirstName = p.FirstName,
                        DateOfBirth = p.DateOfBirth,
                        LastName = p.LastName,
                        TeamId = p.TeamId
                    }).ToList()
                }).ToListAsync();

EF“异步”与Select into DTO对象

context.Players.Select(p => new PlayerDTO() { Id = p.Id, FirstName = p.FirstName, DateOfBirth = p.DateOfBirth, LastName = p.LastName, TeamId = p.TeamId }).FirstOrDefault(x => x.Id == id); context.Players.Where(x => x.TeamId == teamId).Select(p => new PlayerDTO() { Id = p.Id, FirstName = p.FirstName, DateOfBirth = p.DateOfBirth, LastName = p.LastName, TeamId = p.TeamId }).ToList(); context.Teams.Where(x => x.SportId == sportId).Select(t => new TeamDTO() { Id = t.Id, FoundingDate = t.FoundingDate, Name = t.Name, SportId = t.SportId, Players = t.Players.Select(p => new PlayerDTO() { Id = p.Id, FirstName = p.FirstName, DateOfBirth = p.DateOfBirth, LastName = p.LastName, TeamId = p.TeamId }).ToList() }).ToList();

await context.Players.Select(p => new PlayerDTO() { Id = p.Id, FirstName = p.FirstName, DateOfBirth = p.DateOfBirth, LastName = p.LastName, TeamId = p.TeamId }).FirstOrDefaultAsync(x => x.Id == id); await context.Players.Where(x => x.TeamId == teamId).Select(p => new PlayerDTO() { Id = p.Id, FirstName = p.FirstName, DateOfBirth = p.DateOfBirth, LastName = p.LastName, TeamId = p.TeamId }).ToListAsync(); await context.Teams.Where(x => x.SportId == sportId).Select(t => new TeamDTO() { Id = t.Id, FoundingDate = t.FoundingDate, Name = t.Name, SportId = t.SportId, Players = t.Players.Select(p => new PlayerDTO() { Id = p.Id, FirstName = p.FirstName, DateOfBirth = p.DateOfBirth, LastName = p.LastName, TeamId = p.TeamId }).ToList() }).ToListAsync();
我想我的结果很麻烦。主要是因为MS正在大量提升EF的异步部分
我的结果：（以毫秒为单位）
运动项目数量：8个，团队数量：30个，运动员数量：100个

EntityFrameworkAsyncDTO Results Run # Player by ID Players per Team Teams per Sport 0 1,46 3,47 35,88 1 1,04 3 33 2 1,02 3,3 33,75 3 1,03 3 31,75 4 1,1 3,27 31,38 EntityFrameworkAsync Results Run # Player by ID Players per Team Teams per Sport 0 1,17 3,53 57 1 1,01 3 48,62 2 0,99 3,03 47,88 3 1,02 3,07 51 4 1 3,03 48,88 EntityFrameworkDTO Results Run # Player by ID Players per Team Teams per Sport 0 0,02 3 13,25 1 0,01 2,8 13,12 2 0,15 2,97 13,25 3 0,02 2,9 13,25 4 0,05 2,8 13,12 EntityFramework Results Run # Player by ID Players per Team Teams per Sport 0 0,01 2,27 28,38 1 0,01 2,4 28,25 2 0 2,13 28,5 3 0,01 2,17 27,5 4 0,01 2,13 29 ADONET Results Run # Player by ID Players per Team Teams per Sport 0 0 2,03 11,75 1 0 2 12,62 2 0 2 11,38 3 0 2 12,38 4 0 2 11,25
/编辑我已将ADO.NET时间添加到结果列表中作为参考
我的问题是：由于加载时间如此不同，我的查询是否做错了什么
在我运行的真实系统中，我将所有的异步DB调用更改为同步调用，从统计数据中可以看出，系统的DB调用速度提高了约50%。这是一个有100-120个当前用户通过信号机连接的系统，它的分贝很重。
我想详细解释一下

Async速度不快，在普通的“sync”代码的基础上增加了很多开销。但它允许在浪费等待时间的情况下更好地使用资源（例如网络连接的高延迟等）
异步方法意味着更多的IL代码，从而解释了一次性调用的这些差异
如果在方法中进行其他异步调用，则可以获得异步方法的好处

另一篇有趣的文章：
如果您按如下方式运行异步测试，我同意其他贡献者的观点：

var tskPlayers = context.Players.FirstOrDefaultAsync(x => x.Id == id); var tskPlayersNt = context.Players.AsNoTracking().Where(x => x.TeamId == teamId).ToListAsync(); var tskTeamsNt = context.Teams.AsNoTracking().Include(x => x.Players).Where(x => x.SportId == sportId).ToListAsync(); Task.WhenAll(tskPlayers, tskPlayersNt, tskTeamsNt);

您将看到更好的结果。
您希望比较First与FirstAsync，并查找与FindAsync的比较。首先，你会发现你做了很多不同的工作。而且，
Async
并不是“更快”。这会增加很多开销。但它允许在等待网络通信时使用时间。我知道Async/Await有开销，但我不认为通过EF进行的SQL调用会慢2-4倍。我知道Find与First不同。我已经将代码改为使用First而不是FindAsync，在使用大型列（如varbinary（MAX）、varchar（MAX）、nvarchar（MAX）或XML）时，这种情况也会变得更糟。请参阅：测试会多次运行。