带有 EF Core 和 Pomelo 的 SocketException (995)

Question

我的应用程序有时会抛出此异常：
MySqlConnector.MySqlException (0x80004005): Connect Timeout expired. All pooled connections are in use.

我从托管服务提供商处发现，我的应用程序的 mysql 中有很多空闲连接。

因此我尝试通过在连接字符串中添加POOLING=FALSE 来禁用池。相反，我得到了以下异常。

 ---> MySqlConnector.MySqlException (0x80004005): The Command Timeout expired before the operation completed.
 ---> System.IO.IOException: Unable to read data from the transport connection: The I/O operation has been aborted because of either a thread exit or an application request..
 ---> System.Net.Sockets.SocketException (995): The I/O operation has been aborted because of either a thread exit or an application request.
   --- End of inner exception stack trace ---
   at System.Net.Sockets.Socket.AwaitableSocketAsyncEventArgs.ThrowException(SocketError error, CancellationToken cancellationToken)
   at System.Net.Sockets.Socket.AwaitableSocketAsyncEventArgs.GetResult(Int16 token)
   at System.Net.Security.SslStream.<FillBufferAsync>g__InternalFillBufferAsync|215_0[TReadAdapter](TReadAdapter adap, ValueTask`1 task, Int32 min, Int32 initial)
   at System.Net.Security.SslStream.ReadAsyncInternal[TReadAdapter](TReadAdapter adapter, Memory`1 buffer)
   at MySqlConnector.Protocol.Serialization.StreamByteHandler.<ReadBytesAsync>g__DoReadBytesAsync|6_2(Memory`1 buffer) in /_/src/MySqlConnector/Protocol/Serialization/StreamByteHandler.cs:line 89
   at MySqlConnector.Protocol.Serialization.StreamByteHandler.<ReadBytesAsync>g__DoReadBytesAsync|6_2(Memory`1 buffer) in /_/src/MySqlConnector/Protocol/Serialization/StreamByteHandler.cs:line 89
   at MySqlConnector.Protocol.Serialization.BufferedByteReader.ReadBytesAsync(IByteHandler byteHandler, ArraySegment`1 buffer, Int32 totalBytesToRead, IOBehavior ioBehavior) in /_/src/MySqlConnector/Protocol/Serialization/BufferedByteReader.cs:line 36
   at MySqlConnector.Protocol.Serialization.ProtocolUtility.<ReadPacketAsync>g__AddContinuation|1_0(ValueTask`1 headerBytes, BufferedByteReader bufferedByteReader, IByteHandler byteHandler, Func`1 getNextSequenceNumber, ProtocolErrorBehavior protocolErrorBehavior, IOBehavior ioBehavior) in /_/src/MySqlConnector/Protocol/Serialization/ProtocolUtility.cs:line 412
   at MySqlConnector.Protocol.Serialization.ProtocolUtility.<DoReadPayloadAsync>g__AddContinuation|5_0(ValueTask`1 readPacketTask, BufferedByteReader bufferedByteReader, IByteHandler byteHandler, Func`1 getNextSequenceNumber, ArraySegmentHolder`1 previousPayloads, ProtocolErrorBehavior protocolErrorBehavior, IOBehavior ioBehavior) in /_/src/MySqlConnector/Protocol/Serialization/ProtocolUtility.cs:line 483
   at MySqlConnector.Core.ServerSession.ReceiveReplyAsyncAwaited(ValueTask`1 task) in /_/src/MySqlConnector/Core/ServerSession.cs:line 890
   at MySqlConnector.Core.ResultSet.ReadResultSetHeaderAsync(IOBehavior ioBehavior) in /_/src/MySqlConnector/Core/ResultSet.cs:line 50
   at MySqlConnector.MySqlDataReader.ActivateResultSet(CancellationToken cancellationToken) in /_/src/MySqlConnector/MySqlDataReader.cs:line 119
   at MySqlConnector.MySqlDataReader.CreateAsync(CommandListPosition commandListPosition, ICommandPayloadCreator payloadCreator, IDictionary`2 cachedProcedures, IMySqlCommand command, CommandBehavior behavior, IOBehavior ioBehavior, CancellationToken cancellationToken) in /_/src/MySqlConnector/MySqlDataReader.cs:line 445
   at MySqlConnector.Core.CommandExecutor.ExecuteReaderAsync(IReadOnlyList`1 commands, ICommandPayloadCreator payloadCreator, CommandBehavior behavior, IOBehavior ioBehavior, CancellationToken cancellationToken) in /_/src/MySqlConnector/Core/CommandExecutor.cs:line 60
   at MySqlConnector.MySqlCommand.ExecuteReaderAsync(CommandBehavior behavior, IOBehavior ioBehavior, CancellationToken cancellationToken) in /_/src/MySqlConnector/MySqlCommand.cs:line 315
   at MySqlConnector.MySqlCommand.ExecuteDbDataReaderAsync(CommandBehavior behavior, CancellationToken cancellationToken) in /_/src/MySqlConnector/MySqlCommand.cs:line 307
   at Microsoft.EntityFrameworkCore.Storage.RelationalCommand.ExecuteReaderAsync(RelationalCommandParameterObject parameterObject, CancellationToken cancellationToken)
   at Microsoft.EntityFrameworkCore.Storage.RelationalCommand.ExecuteReaderAsync(RelationalCommandParameterObject parameterObject, CancellationToken cancellationToken)
   at Microsoft.EntityFrameworkCore.Query.Internal.SingleQueryingEnumerable`1.AsyncEnumerator.InitializeReaderAsync(DbContext _, Boolean result, CancellationToken cancellationToken)
   at Microsoft.EntityFrameworkCore.Storage.ExecutionStrategy.ExecuteImplementationAsync[TState,TResult](Func`4 operation, Func`4 verifySucceeded, TState state, CancellationToken cancellationToken)
   --- End of inner exception stack trace ---
   at Microsoft.EntityFrameworkCore.Storage.ExecutionStrategy.ExecuteImplementationAsync[TState,TResult](Func`4 operation, Func`4 verifySucceeded, TState state, CancellationToken cancellationToken)
   at Microsoft.EntityFrameworkCore.Query.Internal.SingleQueryingEnumerable`1.AsyncEnumerator.MoveNextAsync()
   at Microsoft.EntityFrameworkCore.EntityFrameworkQueryableExtensions.ToListAsync[TSource](IQueryable`1 source, CancellationToken cancellationToken)
   at Microsoft.EntityFrameworkCore.EntityFrameworkQueryableExtensions.ToListAsync[TSource](IQueryable`1 source, CancellationToken cancellationToken)
   at Microsoft.AspNetCore.Identity.EntityFrameworkCore.UserStore`9.GetRolesAsync(TUser user, CancellationToken cancellationToken)
   at Microsoft.AspNetCore.Identity.UserManager`1.GetRolesAsync(TUser user)
   at Microsoft.AspNetCore.Identity.UserClaimsPrincipalFactory`2.GenerateClaimsAsync(TUser user)
   at Microsoft.AspNetCore.Identity.UserClaimsPrincipalFactory`1.CreateAsync(TUser user)
   at Microsoft.AspNetCore.Identity.SignInManager`1.CreateUserPrincipalAsync(TUser user)
   at Microsoft.AspNetCore.Identity.SecurityStampValidator`1.SecurityStampVerified(TUser user, CookieValidatePrincipalContext context)
   at Microsoft.AspNetCore.Identity.SecurityStampValidator`1.ValidateAsync(CookieValidatePrincipalContext context)
   at Microsoft.AspNetCore.Authentication.Cookies.CookieAuthenticationHandler.HandleAuthenticateAsync()
   at Microsoft.AspNetCore.Authentication.AuthenticationHandler`1.AuthenticateAsync()
   at Microsoft.AspNetCore.Authentication.AuthenticationService.AuthenticateAsync(HttpContext context, String scheme)
   at Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.ResponseCompression.ResponseCompressionMiddleware.Invoke(HttpContext context)

我想知道是什么导致了这个异常，以及处理空闲 mysql 连接问题的更好方法是什么。

Answer 1

因此我尝试通过在连接字符串中添加POOLING=FALSE 来禁用池。相反，我得到了以下异常。

您得到---> MySqlConnector.MySqlException (0x80004005): The Command Timeout expired before the operation completed. 异常的原因很可能是最大值。您的 MySQL 实例的连接已经耗尽。

如果您不想重新配置 MySQL 实例，让您的应用运行的最简单方法是禁用连接池（就像您已经做过的那样），然后重新启动服务器（以确保没有来自您的旧代码阻止您连接）。

---

如果你毕竟想使用连接池，你可能还想看看 MySqlConnector 的Connection Pooling Options。

它们包含用于管理连接池的连接数量及其生命周期的选项（默认数量为100，默认生命周期为无限）。

特别要仔细看看MaxPoolSize和ConnectionIdleTimeout。

另外，请确保您的连接字符串不会更改。 MySqlConnector（以及 Pomelo）为每个唯一的连接字符串使用一个专用的连接池。

---

除此之外，在 MySQL 数据库级别，您可以使用 wait_timeout 选项强制在特定超时后关闭连接。

它的默认值通常是28800（8 小时）。

Answer 2

1.Connection Timeout=300（以秒为单位的时间）

2.默认命令超时=300（时间以秒为单位）

像这样使用你的连接：-

"ConnectionStrings": {  
    "DefaultConnection": "server=localhost; port=3306; database=dbname; user=username; password=yourpassword; Persist Security Info=False; Connect Timeout=300;default command timeout=300"  
  } 

或者

"server=yourservername;userid=xxxxx;password=xxxxx;database=xxxxx;Connection Timeout=300;default command timeout=300"

或者你可以定义 Time out on Startup 类如下：-

services.AddDbContext<YourDbContextName>(options =>
                options.UseMySql(
                    Configuration.GetConnectionString("DefaultConnection"), o => o.CommandTimeout(180)));

它将解决您的问题。