c# - MongoClient 的生命周期应该如何工作？

Question

我有一个使用 MongoDB 作为数据库的 ASP.Net MVC 应用程序。网站和数据库位于不同的服务器上。

目前，我有一个看起来像这样的类:

public class Mongo
{
    private IMongoDatabase database;

    public Mongo()
    {
        var client = new MongoClient("mongodb://username:password@ipaddress:port");
        database = client.GetDatabase("MyDatabase");
    }

    public IMongoCollection<ApplicationUser> Users() { return database.GetCollection<ApplicationUser>("Users"); }
}

所以要使用它...(基本上在每个请求中)

Mongo mon = new Mongo();
mon.Users.Find(........); // etc.

这工作正常 - 大多数时候。在奇怪的情况下，事情似乎被锁定并且数据库只是超时，直到我重新启动网站。我在尝试连接到数据库服务器时遇到超时错误。

在此过程中，数据库服务器已确认，我可以从另一个 mongo 客户端连接到 MongoDB，而不会出现问题。

我意识到这没有发生“密切联系”的事情 - 但似乎没有一个甚至可以打电话。所以我想知道这是否与打开太多连接并且没有正确清理有关。

我是否错误地使用了 MongoClient？我应该做些什么来阻止这些超时？

这是我得到的错误的痕迹:

   [SocketException (0x274c): A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond ipaddress:port]
       System.Net.Sockets.Socket.EndConnect(IAsyncResult asyncResult) +6768957
       System.Threading.Tasks.TaskFactory`1.FromAsyncCoreLogic(IAsyncResult iar, Func`2 endFunction, Action`1 endAction, Task`1 promise, Boolean requiresSynchronization) +57
       System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +99
       System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58
       System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd(Task task) +25
       MongoDB.Driver.Core.Connections.<ConnectAsync>d__7.MoveNext() +1542
       System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +99
       System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58
       MongoDB.Driver.Core.Connections.<CreateStreamAsync>d__0.MoveNext() +345
       System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +99
       System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58
       MongoDB.Driver.Core.Connections.<OpenAsyncHelper>d__1.MoveNext() +553

[MongoConnectionException: An exception occurred while opening a connection to the server.]
   MongoDB.Driver.Core.Connections.<OpenAsyncHelper>d__1.MoveNext() +1372
   System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +99
   System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58
   MongoDB.Driver.Core.Servers.<GetChannelAsync>d__0.MoveNext() +548
   System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +99
   System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58
   System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd(Task task) +25
   MongoDB.Driver.Core.Operations.<ExecuteAsync>d__2.MoveNext() +639
   System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +99
   System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58
   MongoDB.Driver.<ExecuteReadOperationAsync>d__0`1.MoveNext() +272
   System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +99
   System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58
   MongoDB.Driver.<ExecuteReadOperation>d__35`1.MoveNext() +396
   System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +99
   System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58
   MongoDB.Driver.<ToListAsync>d__14`1.MoveNext() +294

Answer 1

您正在错误地使用 MongoClient。如 the docs 中所示

It is recommended to store a MongoClient instance in a global place, either as a static variable or in an IoC container with a singleton lifetime.

因此，您应该重新编写代码以创建单例 MongoClient 实例，然后在整个程序中使用它。

原因是 MongoClient 维护了一个开放连接池，可以共享和重用以获得最佳性能。