運行 Scaffold-DbContext 時出現超時錯誤

Question

我們使用數據優先的方法，並使用 Scaffol-Dbcontext 對數據上下文進行逆向工程。

數據庫是 MySQL，我們使用 Pomelo 作為提供者。

它在 283 個數據庫版本上運行良好，但現在命令崩潰並出現錯誤：

命令超時在操作完成之前到期。

這是我使用的命令：

Scaffold-DbContext "server=localhost;userid=user;pwd=pass;port=3306;database=db_name;sslmode=none;" "Pomelo.EntityFrameworkCore.MySql" -d -o "OutputFolder" -v -f -context "ContextName"

這是完整的堆棧跟蹤：

MySql.Data.MySqlClient.MySqlException (0x80004005): The Command Timeout expired before the operation completed. ---> MySql.Data.MySqlClient.MySqlException (0x80004005): The Command Timeout expired before the operation completed.
   at MySqlConnector.Protocol.Serialization.BufferedByteReader.ReadBytesAsync(IByteHandler byteHandler, ArraySegment`1 buffer, Int32 totalBytesToRead, IOBehavior ioBehavior) in C:\projects\mysqlconnector\src\MySqlConnector\Protocol\Serialization\BufferedByteReader.cs:line 36
   at MySqlConnector.Protocol.Serialization.ProtocolUtility.ReadPacketAsync(BufferedByteReader bufferedByteReader, IByteHandler byteHandler, Func`1 getNextSequenceNumber, ProtocolErrorBehavior protocolErrorBehavior, IOBehavior ioBehavior) in C:\projects\mysqlconnector\src\MySqlConnector\Protocol\Serialization\ProtocolUtility.cs:line 406
   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 459
   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 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.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state)
--- End of stack trace from previous location where exception was thrown ---
   at System.Threading.Tasks.Task.ExecuteWithThreadLocal(Task& currentTaskSlot)
--- End of stack trace from previous location where exception was thrown ---
   at MySqlConnector.Core.ResultSet.ReadResultSetHeaderAsync(IOBehavior ioBehavior) in C:\projects\mysqlconnector\src\MySqlConnector\Core\ResultSet.cs:line 42
   at MySql.Data.MySqlClient.MySqlDataReader.ActivateResultSet(ResultSet resultSet) in C:\projects\mysqlconnector\src\MySqlConnector\MySql.Data.MySqlClient\MySqlDataReader.cs:line 74
   at MySql.Data.MySqlClient.MySqlDataReader.ReadFirstResultSetAsync(IOBehavior ioBehavior) in C:\projects\mysqlconnector\src\MySqlConnector\MySql.Data.MySqlClient\MySqlDataReader.cs:line 299
   at MySql.Data.MySqlClient.MySqlDataReader.CreateAsync(MySqlCommand command, CommandBehavior behavior, ResultSetProtocol resultSetProtocol, IOBehavior ioBehavior) in C:\projects\mysqlconnector\src\MySqlConnector\MySql.Data.MySqlClient\MySqlDataReader.cs:line 284
   at MySqlConnector.Core.TextCommandExecutor.ExecuteReaderAsync(String commandText, MySqlParameterCollection parameterCollection, CommandBehavior behavior, IOBehavior ioBehavior, CancellationToken cancellationToken) in C:\projects\mysqlconnector\src\MySqlConnector\Core\TextCommandExecutor.cs:line 37
   at MySql.Data.MySqlClient.MySqlCommand.ExecuteDbDataReader(CommandBehavior behavior) in C:\projects\mysqlconnector\src\MySqlConnector\MySql.Data.MySqlClient\MySqlCommand.cs:line 252
   at Pomelo.EntityFrameworkCore.MySql.Scaffolding.Internal.MySqlDatabaseModelFactory.GetConstraints()
   at Pomelo.EntityFrameworkCore.MySql.Scaffolding.Internal.MySqlDatabaseModelFactory.Create(DbConnection connection, IEnumerable`1 tables, IEnumerable`1 schemas)
   at Pomelo.EntityFrameworkCore.MySql.Scaffolding.Internal.MySqlDatabaseModelFactory.Create(String connectionString, IEnumerable`1 tables, IEnumerable`1 schemas)
   at Microsoft.EntityFrameworkCore.Scaffolding.Internal.ReverseEngineerScaffolder.ScaffoldModel(String connectionString, IEnumerable`1 tables, IEnumerable`1 schemas, String namespace, String language, String contextDir, String contextName, ModelReverseEngineerOptions modelOptions, ModelCodeGenerationOptions codeOptions)
   at Microsoft.EntityFrameworkCore.Design.Internal.DatabaseOperations.ScaffoldContext(String provider, String connectionString, String outputDir, String outputContextDir, String dbContextClassName, IEnumerable`1 schemas, IEnumerable`1 tables, Boolean useDataAnnotations, Boolean overwriteFiles, Boolean useDatabaseNames)
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.ScaffoldContextImpl(String provider, String connectionString, String outputDir, String outputDbContextDir, String dbContextClassName, IEnumerable`1 schemaFilters, IEnumerable`1 tableFilters, Boolean useDataAnnotations, Boolean overwriteFiles, Boolean useDatabaseNames)
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.ScaffoldContext.<>c__DisplayClass0_1.<.ctor>b__0()
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.<>c__DisplayClass3_0`1.<Execute>b__0()
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.Execute(Action action)

相關包版本：

• Microsoft.AspNetCore.All 2.1.4
• Pomelo.EntityFrameworkCore.MySql 2.1.2

需要注意的是，這只發生在我的電腦上（VS Professional 2017 v15.8.5）。 其他同事可以運行相同的命令，並備份我的數據庫，而不會出現任何錯誤。

你能為我指出正確的方向嗎？ 到目前為止，我已經測試過（沒有成功）：

• 更新所有軟件包。
• 更新 Visual Studio
• 刪除 nuget 文件夾並恢復包
• 嘗試了幾個數據庫（有些工作，有些沒有，但不確定它們之間有什么區別）
• 將“Connect timeout=300”屬性添加到連接字符串（同樣的錯誤，但需要 5 分鍾）

Answer 1

下次嘗試添加

1. 連接超時=300（以秒為單位的時間）
2. 默認命令超時=300（以秒為單位的時間）

嘗試以下連接字符串：

dotnet ef dbcontext scaffold "server=simycotest.ddns.net;userid=xxxxx;password=xxxxx;database=xxxxx;Connection Timeout=300;default command timeout=300" "Pomelo.EntityFrameworkCore.MySql" -o .\DbModels -f

有關MySql 中的連接字符串的更多信息

Answer 2

在 .NET 6 中，您不能添加default command timeout ，但可以使用command timeout
我通過運行這篇文章dotnet sqlclient github解決了這個問題

如上面鏈接中所述，您可以將超時值都設置為 0 以完全禁用超時。
我必須這樣做，因為數據庫的表數量超過 1000 個，並且通過模式構建db模式非常復雜。

Answer 3

抱歉，這個答案並沒有像預期的那樣解決問題，但是我需要在星期一工作，所以我走上了懦夫之路：

卸載與 Visual Studio 和 MySQL 相關的所有內容並重新安裝，一切正常。

它還將 Scaffold-DbContext 運行所需的時間從約 3 分鍾減少到約 10 秒。

僅作記錄，我上次的測試證明只導入 1 個具有 5 個以上 FK 約束的表，該過程失敗。 刪除任何 FK 都會使該過程正常工作...

我的直覺告訴我某個地方的某些損壞的包導致了這種情況。