title: Oracle Data Provider for .NET: Connection request timed out
body: <p>We have a C# WCF web service hosted on Windows 2008 SP2/IIS 7 accessing an Oracle database. Usually data access works fine but during load testing, it often times out and logs and exception saying:</p>
  
  <pre><code>Error occurred when processing XXXXXXXX Web Service
  Oracle.DataAccess.Client.OracleException Connection request timed out at Oracle.DataAccess.Client.OracleException.HandleErrorHelper(Int32 errCode, OracleConnection conn, IntPtr opsErrCtx, OpoSqlValCtx* pOpoSqlValCtx, Object src, String procedure, Boolean bCheck)
     at Oracle.DataAccess.Client.OracleException.HandleError(Int32 errCode, OracleConnection conn, IntPtr opsErrCtx, Object src)
     at Oracle.DataAccess.Client.OracleConnection.Open()
     at MyWorkspace.WorkForceDataAccess.CheckStaffIdInRSW()
     at MyWorkspace.MyClass.MyFunction(MyDataType MyData)
  </code></pre>
  
  <p>To query the database, we use something like this:</p>
  
  <pre><code>OracleConnection orConn = new OracleConnection();
  orConn.ConnectionString = "user id=xxx; password=xxx; Connection Timeout=600; Max Pool Size=150; data source= (DESCRIPTION =(ADDRESS = (PROTOCOL = TCP)(HOST = MYHOST.MYDOMAIN.com)(PORT = 1771)) (CONNECT_DATA =(SERVER = DEDICATED)(SERVICE_NAME = MYSERVICE.MYDOMAIN.com)))";
  orConn.Open();
  
  using (var cmd = new OracleCommand("MY_UTIL.check_StaffIdInRSW", orConn) { CommandType = CommandType.StoredProcedure })
  {
      cmd.Parameters.Add("P_Staff_Id", OracleDbType.Int32);
      cmd.Parameters["P_Staff_Id"].Direction = ParameterDirection.Input;
      cmd.Parameters["P_Staff_Id"].Value = Convert.ToInt32(MyDataObject.StaffId);
  
      cmd.Parameters.Add("P_retvalue", OracleDbType.Int32);
      cmd.Parameters["P_retvalue"].Direction = ParameterDirection.Output;
  
      cmd.ExecuteNonQuery(); // Execute the function
  
      //obtain result
      returnVal = int.Parse(cmd.Parameters["P_retvalue"].Value.ToString());
  }
  </code></pre>
  
  <p>I am pretty confident that the stored procedure that is being invoked is not taking all the time. It is a pretty simple procedure that quickly checks if the P_Staff_Id exists in the table and returns the result.</p>
  
  <p>Additionally, this occurs only during load testing. During normal operations things are fine but during heavy loads with 1 message per second, this occurs after running smooth for some time.</p>
  
  <p>As a workaround, I have added "Connection Timeout=600; Max Pool Size=150“ to the connection string, but that did not fix the issue.</p>
  
  <p>We have the same application running on a development server and it works fine. We never encountered this problem there.</p>
  
  <p>Any suggestions as to what to try would be appreciated. It looks like I am running out of options.</p>