STAThread and OracleConnection.OpenAsync

[FJGR65]

(ODP NET 23.6.1 with .NET Framework 4.8) OracleConnection.OpenAsync does not work when we have a WPF (STAThread) application. The application hangs when trying to open the connection asynchronously.

`
OracleConnection cn = new OracleConnection("DATA SOURCE=XXXXXX:1521/XE;PASSWORD=YYYYY;USER ID=ZZZZZ");

  //The application does indeed open the connection, but hangs when trying to return to the main process.
  //await cn.OpenAsync().ConfigureAwait(false); // The application hangs

  //Solution:
  await Task.Run(async () => await cn.OpenAsync().ConfigureAwait(false)).ConfigureAwait(false);

  Thread.Sleep(1000);
  cn.Close();
  cn = null;

`

Viewing the end of trace file:

2024-12-12 12:22:57.943403 TID:5 (PRI) (EXT) (CID1) OracleConnection.OnConnectionOpen()
2024-12-12 12:22:57.949574 TID:5 (PRI) (ENT) (CID1) OracleConnectionImpl.InitializeDBSvcProperties()
2024-12-12 12:22:57.949574 TID:5 (PRI) (CID1) DB Svc AC Properties =>
2024-12-12 12:22:57.949574 TID:5 (PRI) (CID1) Application Continuity (AC/TAC) NOT Enabled on the connection
2024-12-12 12:22:57.960385 TID:5 (PRI) (SVC) (ENT) (CID1) OracleConnectionImpl.InitializeTAF()
2024-12-12 12:22:57.960385 TID:5 (PRI) (SVC) (CID1) TAF disabled through FAILOVER_TYPE=NONE configured on the connection string
2024-12-12 12:22:57.960385 TID:5 (PRI) (SVC) (EXT) (CID1) OracleConnectionImpl.InitializeTAF()
2024-12-12 12:22:57.961997 TID:5 (PRI) (SVC) (ENT) (CID1) OracleTransactionImpl.ctor()
2024-12-12 12:22:57.961997 TID:5 (PRI) (SVC) (EXT) (CID1) OracleTransactionImpl.ctor()
2024-12-12 12:22:57.961997 TID:5 (PRI) (SVC) (ENT) (CID1) OracleConnectionImpl.SetAutoCommit()
2024-12-12 12:22:57.961997 TID:5 (PRI) (SVC) (EXT) (CID1) OracleConnectionImpl.SetAutoCommit()
2024-12-12 12:22:57.966456 TID:5 (PRI) (SVC) (ENT) OracleGlobalizationImpl.GetLocaleSpecificNLSValues() Connecting with session time zone as :Europe/Paris
2024-12-12 12:22:57.972639 TID:5 (PRI) (ENT) (CID1) OracleConnection.OnStateChange()
2024-12-12 12:22:57.972639 TID:5 (PRI) (EXT) (CID1) OracleConnection.OnStateChange()
2024-12-12 12:22:57.972639 TID:5 (PRI) (CP) (CID1) OracleConnection.Open() (GET) (ENDSID=13:54549)
2024-12-12 12:22:57.973770 TID:5 (PUB) (EXT) (CID1) OracleConnection.OpenInternal() (conid=36328474) (state=Open) (sessid=13) (implid=49538252) (pooling=T) (CID1) (aff=n/a) (inst=xe) (affmatch=n/a) (pr.service=xe) (pr.pdb=) (pr.edition=) (sessid=13:54549) (T;F;F;xe;N) (pmid=47542785) (DISP) (service=xe;inst=xe;used=1;idle=0;tot=1)
2024-12-12 12:22:57.973770 TID:5 (PUB) (EXT) (CID1) OracleConnection.OpenAsyncHelper() //Hangs

[alexkeh]

I don't typically work with Windows Forms. Can you share a complete test case with the hanging behavior? The ODP.NET team and I can review it. It probably has something to do with using single-threaded apartments with ODP.NET async.

[FJGR65]

The project is quite complex, since depending on the arguments in the program call, it can work as a console application or as a WPF (Windows Presentation Fundation) application. This project is almost entirely asynchronous, and has been working correctly with Oracle.ManagedDataAccess 21.x correctly, although I know that the methods are not asynchronous. However, when testing with version 23.x it hangs when establishing the connection.

I have tried to make a simple project, but in this simple project the mentioned error does not occur.

I just wanted to point out that when this error occurs, I have found this alternative solution.

[FJGR65]

I have created a simple Windows Forms project where the above occurs.

ConsoleApp3.zip

[alexkeh]

@FJGR65 Can you re-zip your Windows Forms app? I'm getting errors unzipping it.

[FJGR65]

Sorry, I packed it with "7z" with some non-standard parameters. I'll upload it again and hope there won't be any problems unzipping it.

ConsoleApp3.zip

[alexkeh]

@FJGR65 Thanks for the straightforward test case. I was able to reproduce the hang you experienced. I've filed Bug 37395788 for the ODP.NET team to review the test case and diagnose the problem.