之前項目在測試服務器上的一些接口時不時會報出下面的錯誤：（采用Abp框架）
"SocketException: 你的主機中的軟件中止了一個已建立的連接。 STACK TRACE: at MySqlConnector.Protocol.Serialization.SocketByteHandler.WriteBytesAsync(ArraySegment`1 data, IOBehavior ioBehavior) in C:\projects\mysqlconnector\src\MySqlConnector\Protocol\Serialization\SocketByteHandler.cs:line 90 --- End of stack trace from previous location where exception was thrown --- at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at MySqlConnector.Utilities.ValueTaskExtensions.<ContinueWith>d__0`2.MoveNext() in C:\projects\mysqlconnector\src\MySqlConnector\Utilities\ValueTaskExtensions.cs:line 8 --- End of stack trace from previous location where exception was thrown --- at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at MySqlConnector.Core.ServerSession.TryAsyncContinuation(Task`1 task) in C:\projects\mysqlconnector\src\MySqlConnector\Core\ServerSession.cs:line 1225 at System.Threading.Tasks.ContinuationResultTaskFromResultTask`2.InnerInvoke() at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Threading.Tasks.Task.ExecuteWithThreadLocal(Task& currentTaskSlot) --- End of stack trace from previous location where exception was thrown --- at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at MySqlConnector.Core.TextCommandExecutor.<ExecuteReaderAsync>d__1.MoveNext() in C:\projects\mysqlconnector\src\MySqlConnector\Core\TextCommandExecutor.cs:line 36 --- End of stack trace from previous location where exception was thrown --- at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at MySql.Data.MySqlClient.MySqlCommand.<ExecuteNonQueryAsync>d__60.MoveNext() in C:\projects\mysqlconnector\src\MySqlConnector\MySql.Data.MySqlClient\MySqlCommand.cs:line 261 --- End of stack trace from previous location where exception was thrown --- at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at MySql.Data.MySqlClient.MySqlCommand.ExecuteNonQuery() in C:\projects\mysqlconnector\src\MySqlConnector\MySql.Data.MySqlClient\MySqlCommand.cs:line 62 at MySql.Data.MySqlClient.MySqlTransaction.Dispose(Boolean disposing) in C:\projects\mysqlconnector\src\MySqlConnector\MySql.Data.MySqlClient\MySqlTransaction.cs:line 81 at Microsoft.EntityFrameworkCore.Storage.RelationalTransaction.Dispose() at Abp.EntityFrameworkCore.Uow.DbContextEfCoreTransactionStrategy.Dispose(IIocResolver iocResolver) at Abp.EntityFrameworkCore.Uow.EfCoreUnitOfWork.DisposeUow() at Abp.Domain.Uow.UnitOfWorkBase.Dispose() at Abp.AspNetCore.Mvc.Uow.AbpUowActionFilter.<OnActionExecutionAsync>d__4.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.<InvokeNextActionFilterAsync>d__10.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Rethrow(ActionExecutedContext context) at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted) at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.<InvokeInnerFilterAsync>d__13.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.<InvokeNextExceptionFilterAsync>d__24.MoveNext() "
MySql.Data.MySqlClient.MySqlException (0x80004005): Failed to read the result set. ---> System.IO.EndOfStreamException: Expected to read 4 header bytes but only received 0. at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at MySqlConnector.Protocol.Serialization.ProtocolUtility.DoReadPayloadAsync(BufferedByteReader bufferedByteReader, IByteHandler byteHandler, Func`1 getNextSequenceNumber, ArraySegmentHolder`1 previousPayloads, ProtocolErrorBehavior protocolErrorBehavior, IOBehavior ioBehavior) in C:\projects\mysqlconnector\src\MySqlConnector\Protocol\Serialization\ProtocolUtility.cs:line 462 at MySqlConnector.Protocol.Serialization.StandardPayloadHandler.ReadPayloadAsync(ArraySegmentHolder`1 cache, ProtocolErrorBehavior protocolErrorBehavior, IOBehavior ioBehavior) in C:\projects\mysqlconnector\src\MySqlConnector\Protocol\Serialization\StandardPayloadHandler.cs:line 37 at MySqlConnector.Core.ServerSession.ReceiveReplyAsync(IOBehavior ioBehavior, CancellationToken cancellationToken) in C:\projects\mysqlconnector\src\MySqlConnector\Core\ServerSession.cs:line 645 --- End of stack trace from previous location where exception was thrown --- at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at MySqlConnector.Core.ServerSession.TryAsyncContinuation(Task`1 task) in C:\projects\mysqlconnector\src\MySqlConnector\Core\ServerSession.cs:line 1230 at System.Threading.Tasks.ContinuationResultTaskFromResultTask`2.InnerInvoke() at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Threading.Tasks.Task.ExecuteWithThreadLocal(Task& currentTaskSlot) --- End of stack trace from previous location where exception was thrown ---
然后我使用swagger+miniprofiler，查看生成的sql語句
查看Mysql錯誤日志：
Aborted connection 422 to db: '數據庫名稱' user: 'root' host: 'localhost' (Got a packet bigger than 'max_allowed_packet' bytes)
可能因為傳輸的數據過大，而Mysql的max_allowed_packet默認為1024b，導致sql執行不成功。
然后將Mysql配置文件中的max_allowed_packet值改為max_allowed_packet = 4M
重啟Mysql，問題解決。
然而過了一段時間，同樣的報錯又出現了，首先看了下max_allowed_packet的值，果然max_allowed_packet又被修改為了1024b，查看命令如下：
show variables like '%max_allowed_packet%';
然后詢問同事，他們說並沒有動數據庫，上網查了下說是有可能是被攻擊了。
於是我開啟了Mysql的日志，命令如下：
set global general_log=on;
在日志里看到了被修改信息，然后看了下ip~~~
還發現了幾個新增用戶TvT，把它刪掉：
查看Mysql用戶命令如下：
select * from mysql.user
目前解決方法是，加強密碼，限制遠程連接ip：把上圖的% 改為指定ip段xxx.xxx.xxx.%，重啟Mysql。