System.InvalidOperationException: Can't replace active reader.

Software versions MySqlConnector version: 2.1.8 Server type (MySQL, MariaDB, Aurora, etc.) and version: Aurora (MySQL 5.7) .NET version: .NET 6 (Optional) ORM NuGet packages and versions: Pomelo 6.0.1

Describe the bug After some usage my application, I start getting pseudo-random exceptions. It doesn’t happen on each call but it happens around 50% of web calls after some time. Restarting the application seems to reset things but they again start to go wrong after a while.

This only happened after the latest update. I changed from version 2.1.6 to 2.1.8. I updated from .NET and EFCore 6.0.2 to 6.0.3. Pomelo remained the same.

Admittingly there are other code changes but nothing big nor that should do this as I don’t use Readers directly. Only with EFCore. I don’t see connection exhaustion or anything looking at metrics in AWS.

I’m not sure if I’m doing something wrong or where to look for to how to solve this problem. Can’t find anything similar. I’m going to downgrade to 2.1.6 to see if the issue reoccurs. I’m hoping to get some pointers about how to figure out what’s going on.

Exception

System.InvalidOperationException: Can't replace active reader.
   at MySqlConnector.MySqlConnection.SetActiveReader(MySqlDataReader dataReader) in /_/src/MySqlConnector/MySqlConnection.cs:line 874
   at MySqlConnector.MySqlDataReader.CreateAsync(CommandListPosition commandListPosition, ICommandPayloadCreator payloadCreator, IDictionary`2 cachedProcedures, IMySqlCommand command, CommandBehavior behavior, Activity activity, IOBehavior ioBehavior, CancellationToken cancellationToken) in /_/src/MySqlConnector/MySqlDataReader.cs:line 460
   at MySqlConnector.Core.CommandExecutor.ExecuteReaderAsync(IReadOnlyList`1 commands, ICommandPayloadCreator payloadCreator, CommandBehavior behavior, Activity activity, IOBehavior ioBehavior, CancellationToken cancellationToken) in /_/src/MySqlConnector/Core/CommandExecutor.cs:line 56
   at MySqlConnector.MySqlCommand.ExecuteReaderAsync(CommandBehavior behavior, IOBehavior ioBehavior, CancellationToken cancellationToken) in /_/src/MySqlConnector/MySqlCommand.cs:line 344
   at MySqlConnector.MySqlCommand.ExecuteDbDataReaderAsync(CommandBehavior behavior, CancellationToken cancellationToken) in /_/src/MySqlConnector/MySqlCommand.cs:line 337
   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(AsyncEnumerator enumerator, CancellationToken cancellationToken)
   at Microsoft.EntityFrameworkCore.Storage.ExecutionStrategy.<>c__DisplayClass33_0`2.<<ExecuteAsync>b__0>d.MoveNext()
--- End of stack trace from previous location ---
   at Microsoft.EntityFrameworkCore.Storage.ExecutionStrategy.ExecuteImplementationAsync[TState,TResult](Func`4 operation, Func`4 verifySucceeded, TState state, CancellationToken cancellationToken)
   at Microsoft.EntityFrameworkCore.Storage.ExecutionStrategy.ExecuteImplementationAsync[TState,TResult](Func`4 operation, Func`4 verifySucceeded, TState state, CancellationToken cancellationToken)
   at Microsoft.EntityFrameworkCore.Storage.ExecutionStrategy.ExecuteAsync[TState,TResult](TState state, Func`4 operation, Func`4 verifySucceeded, CancellationToken cancellationToken)
   at Microsoft.EntityFrameworkCore.Query.Internal.SingleQueryingEnumerable`1.AsyncEnumerator.MoveNextAsync()
   at Microsoft.EntityFrameworkCore.Query.ShapedQueryCompilingExpressionVisitor.SingleOrDefaultAsync[TSource](IAsyncEnumerable`1 asyncEnumerable, CancellationToken cancellationToken)
   at Microsoft.EntityFrameworkCore.Query.ShapedQueryCompilingExpressionVisitor.SingleOrDefaultAsync[TSource](IAsyncEnumerable`1 asyncEnumerable, CancellationToken cancellationToken)