OracleDataReader के लिए समयबाह्य। विधि पढ़ें

यहाँ वह समाधान है जिसके साथ मैं अंततः गया था। यह OracleDataReader वर्ग के लिए केवल एक विस्तार विधि है। इस विधि में टाइमआउट मान और पैरामीटर के रूप में कॉलबैक फ़ंक्शन है। कॉलबैक फ़ंक्शन आम तौर पर (यदि हमेशा नहीं) OracleCommand.Cancel होगा।

namespace ConsoleApplication1
{
    public static class OracleDataReaderExtensions
    {
        public static bool Read(this OracleDataReader reader, int timeout, Action cancellationAction)
        {
            Task<bool> task = Task<bool>.Factory.StartNew(() => 
                {
                    try
                    {
                        return reader.Read();
                    }
                    catch (OracleException ex)
                    {
                        // When cancellationAction is called below, it will trigger 
                        // an ORA-01013 error in the Read call that is still executing.
                        // This exception can be ignored as we're handling the situation
                        // by throwing a TimeoutException.
                        if (ex.Number == 1013)
                        {
                            return false;
                        }
                        else
                        {
                            throw;
                        }
                    }
                });

            try
            {
                if (!task.Wait(timeout))
                {
                    // call the cancellation callback function (i.e. OracleCommand.Cancel())
                    cancellationAction();

                    // throw an exception to notify calling code that a timeout has occurred
                    throw new TimeoutException("The OracleDataReader.Read operation has timed-out.");
                }
                return task.Result;
            }
            catch (AggregateException ae)
            {
                throw ae.Flatten();
            }
        }
    }
}

इसका उपयोग कैसे किया जा सकता है इसका एक उदाहरण यहां दिया गया है।

namespace ConsoleApplication1
{
    class Program
    {
        static string constring = "User ID=xxxx; Password=xxxx; Data Source=xxxx;";

        static void Main(string[] args)
        {
            using (OracleConnection con = new OracleConnection(constring))
            using (OracleCommand cmd = new OracleCommand())
            {
                cmd.Connection = con;
                con.Open();

                Console.WriteLine("Executing Query...");

                string sql = "<some long running sql>";
                cmd.CommandText = "PROC_A";
                cmd.CommandType = System.Data.CommandType.StoredProcedure;
                cmd.Parameters.Add(new OracleParameter("i_sql", OracleDbType.Varchar2) { Direction = ParameterDirection.Input, Value = sql });
                cmd.Parameters.Add(new OracleParameter("o_cur1", OracleDbType.RefCursor) { Direction = ParameterDirection.Output });

                try
                {
                    // execute command and get reader for ref cursor
                    OracleDataReader reader = cmd.ExecuteReader(CommandBehavior.CloseConnection);

                    // read first record; this is where the ref cursor SQL gets evaluated
                    Console.WriteLine("Reading first record...");
                    if (reader.Read(3000, cmd.Cancel)) { }

                    // read remaining records
                    Console.WriteLine("Reading records 2 to N...");
                    while (reader.Read(3000, cmd.Cancel)) { }
                }
                catch (TimeoutException ex)
                {
                    Console.WriteLine("Exception: {0}", ex.Message);
                }

                Console.WriteLine("Press any key to continue...");
                Console.Read();
            }
        }
    }
}

और यहाँ आउटपुट का एक उदाहरण है।

Executing Query...
Reading first record...
Exception: The OracleDataReader.Read operation has timed-out.
Press any key to continue...