C#•4mo ago

Weirdest problem - catch doesnt work

c#
try
{
    using (var connection = new MySqlConnection("Server=x;Port=3306;Database=x;Uid=x;Pwd=x;Pooling=true"))
    {
        await connection.OpenAsync();
    }
}
catch(Exception ex)
{
    var q2 = "";
}

c#
try
{
    using (var connection = new MySqlConnection("Server=x;Port=3306;Database=x;Uid=x;Pwd=x;Pooling=true"))
    {
        await connection.OpenAsync();
    }
}
catch(Exception ex)
{
    var q2 = "";
}

x is actually my server's info If my server is running, this works ok. But if I reboot my server, this code throws unhandled exception! Basically catch doesnt work!

```System.AggregateException
  HResult=0x80131500
  Message=One or more errors occurred. (Timeout expired.  The timeout period elapsed prior to completion of the operation or the server is not responding.)
  Source=System.Private.CoreLib
  StackTrace:
   at System.Threading.CancellationTokenSource.ExecuteCallbackHandlers(Boolean throwOnFirstException) in /_/src/libraries/System.Private.CoreLib/src/System/Threading/CancellationTokenSource.cs:line 831
   at System.Threading.TimerQueueTimer.Fire(Boolean isThreadPool) in /_/src/libraries/System.Private.CoreLib/src/System/Threading/Timer.cs:line 683
   at System.Threading.TimerQueue.FireNextTimers() in /_/src/libraries/System.Private.CoreLib/src/System/Threading/Timer.cs:line 331
   at System.Threading.ThreadPoolWorkQueue.Dispatch() in /_/src/libraries/System.Private.CoreLib/src/System/Threading/ThreadPoolWorkQueue.cs:line 913
   at System.Threading.PortableThreadPool.WorkerThread.WorkerThreadStart() in /_/src/libraries/System.Private.CoreLib/src/System/Threading/PortableThreadPool.WorkerThread.NonBrowser.cs:line 102

Inner Exception 1:
MySqlException: Timeout expired.  The timeout period elapsed prior to completion of the operation or the server is not responding.

Inner Exception 2:
TimeoutException: The operation has timed out.

```System.AggregateException
  HResult=0x80131500
  Message=One or more errors occurred. (Timeout expired.  The timeout period elapsed prior to completion of the operation or the server is not responding.)
  Source=System.Private.CoreLib
  StackTrace:
   at System.Threading.CancellationTokenSource.ExecuteCallbackHandlers(Boolean throwOnFirstException) in /_/src/libraries/System.Private.CoreLib/src/System/Threading/CancellationTokenSource.cs:line 831
   at System.Threading.TimerQueueTimer.Fire(Boolean isThreadPool) in /_/src/libraries/System.Private.CoreLib/src/System/Threading/Timer.cs:line 683
   at System.Threading.TimerQueue.FireNextTimers() in /_/src/libraries/System.Private.CoreLib/src/System/Threading/Timer.cs:line 331
   at System.Threading.ThreadPoolWorkQueue.Dispatch() in /_/src/libraries/System.Private.CoreLib/src/System/Threading/ThreadPoolWorkQueue.cs:line 913
   at System.Threading.PortableThreadPool.WorkerThread.WorkerThreadStart() in /_/src/libraries/System.Private.CoreLib/src/System/Threading/PortableThreadPool.WorkerThread.NonBrowser.cs:line 102

Inner Exception 1:
MySqlException: Timeout expired.  The timeout period elapsed prior to completion of the operation or the server is not responding.

Inner Exception 2:
TimeoutException: The operation has timed out.

``` How is this possible?

10 Replies

webczat•4mo ago

might be that exception is being thrown from some different context than you expect, like some other thread, not in the async flow?

SoFt•4mo ago

I just have this snip runnig on the main thread, right where the form loads. No other code

webczat•4mo ago

so doesn't correctly propagate but OpenAsync calls into a db provider which can do whatever. the responsible code is the provider.

SoFt•4mo ago

Are you saying there is something wrong with the mysql library? Or that I need to handle it some other way

Pobiega•4mo ago

afaik there are plenty of things wrong with the mysql library, especially the ones not from Pomelo

webczat•4mo ago

there might be something wrong with the mysql library. AggregateException is kinda rare especially in async/await, it is usually seen when doing direct Task manipulation and like... not sure

Jimmacle•4mo ago

do you have the full exception and stack trace? where does it point to?

SoFt•4mo ago

System.AggregateException
  HResult=0x80131500
  Message=One or more errors occurred. (Timeout expired.  The timeout period elapsed prior to completion of the operation or the server is not responding.)
  Source=System.Private.CoreLib
  StackTrace:
   at System.Threading.CancellationTokenSource.ExecuteCallbackHandlers(Boolean throwOnFirstException) in /_/src/libraries/System.Private.CoreLib/src/System/Threading/CancellationTokenSource.cs:line 831
   at System.Threading.TimerQueueTimer.Fire(Boolean isThreadPool) in /_/src/libraries/System.Private.CoreLib/src/System/Threading/Timer.cs:line 683
   at System.Threading.TimerQueue.FireNextTimers() in /_/src/libraries/System.Private.CoreLib/src/System/Threading/Timer.cs:line 331
   at System.Threading.ThreadPoolWorkQueue.Dispatch() in /_/src/libraries/System.Private.CoreLib/src/System/Threading/ThreadPoolWorkQueue.cs:line 913
   at System.Threading.PortableThreadPool.WorkerThread.WorkerThreadStart() in /_/src/libraries/System.Private.CoreLib/src/System/Threading/PortableThreadPool.WorkerThread.NonBrowser.cs:line 102

Inner Exception 1:
MySqlException: Timeout expired.  The timeout period elapsed prior to completion of the operation or the server is not responding.

Inner Exception 2:
TimeoutException: The operation has timed out.

System.AggregateException
  HResult=0x80131500
  Message=One or more errors occurred. (Timeout expired.  The timeout period elapsed prior to completion of the operation or the server is not responding.)
  Source=System.Private.CoreLib
  StackTrace:
   at System.Threading.CancellationTokenSource.ExecuteCallbackHandlers(Boolean throwOnFirstException) in /_/src/libraries/System.Private.CoreLib/src/System/Threading/CancellationTokenSource.cs:line 831
   at System.Threading.TimerQueueTimer.Fire(Boolean isThreadPool) in /_/src/libraries/System.Private.CoreLib/src/System/Threading/Timer.cs:line 683
   at System.Threading.TimerQueue.FireNextTimers() in /_/src/libraries/System.Private.CoreLib/src/System/Threading/Timer.cs:line 331
   at System.Threading.ThreadPoolWorkQueue.Dispatch() in /_/src/libraries/System.Private.CoreLib/src/System/Threading/ThreadPoolWorkQueue.cs:line 913
   at System.Threading.PortableThreadPool.WorkerThread.WorkerThreadStart() in /_/src/libraries/System.Private.CoreLib/src/System/Threading/PortableThreadPool.WorkerThread.NonBrowser.cs:line 102

Inner Exception 1:
MySqlException: Timeout expired.  The timeout period elapsed prior to completion of the operation or the server is not responding.

Inner Exception 2:
TimeoutException: The operation has timed out.

webczat•4mo ago

i don't really know what can cause that. unhandled exception which is thrown from a cancellation callback?

SoFt•4mo ago

I have switched to MySqlConnector and now catch actually works... Thanks for the help

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Weirdest problem - catch doesnt work