sql - Oracle Request Time Out Exception In C# - Stack Overflow

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I have the following code in C# to connect to the Oracle Local DB in C#

using System;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;
using System.Collections.Generic;
using Oracle.ManagedDataAccess.Client;

namespace FirstApp.BAL {
  public class DBManager: IDisposable {
    private OracleConnection _connection;

    public DBManager() {
      try {
        var connectionString = ConfigurationManager.ConnectionStrings["DBConnection"].ConnectionString;
        _connection = new OracleConnection(connectionString);
        _connection.Open(); // You can add this line to test if the connection is successful when the object is created.
      } catch (Exception ex) {
        // Catch specific Oracle exceptions
        Console.WriteLine($"OracleException: {ex.Message}");
        // Console.WriteLine($"Oracle Error Code: {ex.ErrorCode}");
        Console.WriteLine($"Stack Trace: {ex.StackTrace}");
      }
      //catch (Exception ex)
      //{
      //    // Catch any general exceptions
      //    Console.WriteLine($"General Exception: {ex.Message}");
      //    Console.WriteLine($"Stack Trace: {ex.StackTrace}");
      //}
      // You can get the connection string from your Web.config or App.config file.

    }
    public T ExecuteStoredProcedure < T > (string storedProcedure, SqlParameter[] parameters, Func < IDataReader, T > mapFunction) {
      try {
        _connection.Open();
        OracleCommand command = new OracleCommand(storedProcedure, _connection);
        command.CommandType = CommandType.StoredProcedure;

        if (parameters != null) {
          command.Parameters.AddRange(parameters);
        }

        using(OracleDataReader reader = command.ExecuteReader()) {
          if (reader.HasRows) {
            return mapFunction(reader); // Map the result to an object
          } else {
            return default; // Return default if no result is found
          }
        }
      } catch (Exception ex) {
        // Log error
        throw new ApplicationException("An error occurred while executing the stored procedure.", ex);
      } finally {
        _connection.Close();
      }
    }

    public void Dispose() {
      throw new NotImplementedException();
    }
  }
}

I have also checked services of Oracle all are running and smooth (no listener error) but still finding an exception. Can this error be solved?

But using above information SQL-Developer is connecting with the database. I also tried to increase timeout but in vain What is the solution?

I have the following code in C# to connect to the Oracle Local DB in C#

using System;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;
using System.Collections.Generic;
using Oracle.ManagedDataAccess.Client;

namespace FirstApp.BAL {
  public class DBManager: IDisposable {
    private OracleConnection _connection;

    public DBManager() {
      try {
        var connectionString = ConfigurationManager.ConnectionStrings["DBConnection"].ConnectionString;
        _connection = new OracleConnection(connectionString);
        _connection.Open(); // You can add this line to test if the connection is successful when the object is created.
      } catch (Exception ex) {
        // Catch specific Oracle exceptions
        Console.WriteLine($"OracleException: {ex.Message}");
        // Console.WriteLine($"Oracle Error Code: {ex.ErrorCode}");
        Console.WriteLine($"Stack Trace: {ex.StackTrace}");
      }
      //catch (Exception ex)
      //{
      //    // Catch any general exceptions
      //    Console.WriteLine($"General Exception: {ex.Message}");
      //    Console.WriteLine($"Stack Trace: {ex.StackTrace}");
      //}
      // You can get the connection string from your Web.config or App.config file.

    }
    public T ExecuteStoredProcedure < T > (string storedProcedure, SqlParameter[] parameters, Func < IDataReader, T > mapFunction) {
      try {
        _connection.Open();
        OracleCommand command = new OracleCommand(storedProcedure, _connection);
        command.CommandType = CommandType.StoredProcedure;

        if (parameters != null) {
          command.Parameters.AddRange(parameters);
        }

        using(OracleDataReader reader = command.ExecuteReader()) {
          if (reader.HasRows) {
            return mapFunction(reader); // Map the result to an object
          } else {
            return default; // Return default if no result is found
          }
        }
      } catch (Exception ex) {
        // Log error
        throw new ApplicationException("An error occurred while executing the stored procedure.", ex);
      } finally {
        _connection.Close();
      }
    }

    public void Dispose() {
      throw new NotImplementedException();
    }
  }
}

I have also checked services of Oracle all are running and smooth (no listener error) but still finding an exception. Can this error be solved?

But using above information SQL-Developer is connecting with the database. I also tried to increase timeout but in vain What is the solution?

• sql
• oracle-database
• connection

Share Improve this question Follow edited 2 days ago Dale K 27.1k1515 gold badges5555 silver badges8282 bronze badges asked 2 days ago malik hammadmalik hammad 5 3

• Please don't capitalise the start of every word, just the start of every sentence. – Dale K Commented 2 days ago
• You haven't shown the actual error you get, or said which operation throws it (one of the Open calls?), or what debugging you have done - have you checked the connection string you get from your config actually matches what you use in SQL Developer? 'Local DB' suggests same PC perhaps, but it's not clear - is this running from the same machine/PC as SQL Developer and/or the DB, or a VM running on that machine, or on a different machine on the same LAN, or a different network, etc.? It looks like maybe a network or firewall issue, but it could just be misconfigured. – Alex Poole Commented 2 days ago
• I am Facing timeout exception From ORacle Listener is running Service is also running – malik hammad Commented 2 days ago

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1 Answer 1

Sorted by: Reset to default 0

Based on your description and the provided code, the issue seems to lie in the configuration or the connection process itself rather than with the Oracle database services since SQL Developer can successfully connect. Here are some steps to diagnose and resolve the issue:

---

1. Verify Connection String

Ensure your DBConnection connection string in the configuration file (e.g., App.config or Web.config) is correct. The connection string for Oracle typically looks like:

<connectionStrings>
  <add name="DBConnection" 
       connectionString="User Id=<username>;Password=<password>;Data Source=<datasource>" 
       providerName="Oracle.ManagedDataAccess.Client" />
</connectionStrings>

• Replace <username> and <password> with the correct Oracle credentials.

• Replace <datasource> with the appropriate Oracle Data Source, such as:

  • For EZConnect: hostname:port/service_name
    • Example: localhost:1521/XEPDB1
  • For TNS alias: Use the alias defined in tnsnames.ora.

---

2. Check for Oracle.ManagedDataAccess.Client Setup

Ensure you have the Oracle.ManagedDataAccess NuGet package installed in your project. It can be added using:

dotnet add package Oracle.ManagedDataAccess

Make sure the version of this library is compatible with the Oracle database version.

---

3. Debug Exception Details

Update the catch block in your constructor and log detailed exception information:

catch (OracleException oracleEx)
{
    Console.WriteLine($"OracleException: {oracleEx.Message}");
    Console.WriteLine($"Error Code: {oracleEx.ErrorCode}");
    Console.WriteLine($"Stack Trace: {oracleEx.StackTrace}");
}
catch (Exception ex)
{
    Console.WriteLine($"General Exception: {ex.Message}");
    Console.WriteLine($"Stack Trace: {ex.StackTrace}");
}

This will provide more specific details about why the connection fails.

---

4. Verify Network Configuration

• Check TNS Listener: Use the tnsping command to verify the Oracle listener is reachable.

  tnsping <datasource>
  

  Replace <datasource> with your TNS alias or hostname.

• Firewall: Ensure no firewall rules block the connection on port 1521 (or the port used by Oracle).

---

5. Test Connection Using a Minimal C# Example

Try connecting with a minimal example to isolate the problem:

using Oracle.ManagedDataAccess.Client;

class TestOracleConnection
{
    static void Main(string[] args)
    {
        string connectionString = "User Id=<username>;Password=<password>;Data Source=<datasource>";
        
        try
        {
            using (var connection = new OracleConnection(connectionString))
            {
                connection.Open();
                Console.WriteLine("Connection successful!");
            }
        }
        catch (Exception ex)
        {
            Console.WriteLine($"Error: {ex.Message}");
        }
    }
}

---

6. Check Connection Timeout

If the database connection is slow, increase the Connection Timeout in the connection string:

<add name="DBConnection" 
     connectionString="User Id=<username>;Password=<password>;Data Source=<datasource>;Connection Timeout=60" 
     providerName="Oracle.ManagedDataAccess.Client" />

---

7. Ensure Disposal of Resources

The Dispose method in your DBManager class is not implemented. Ensure proper disposal of resources:

public void Dispose()
{
    if (_connection != null)
    {
        if (_connection.State != ConnectionState.Closed)
        {
            _connection.Close();
        }
        _connection.Dispose();
        _connection = null;
    }
}

---

8. Use Explicit .NET Assembly Version

Sometimes, mismatches in versions can cause issues. Verify the correct version of Oracle.ManagedDataAccess assembly is loaded using:

Console.WriteLine(typeof(OracleConnection).Assembly.FullName);

---

9. Check Logs

Look at the Oracle Database logs for any relevant errors, or enable tracing for your Oracle client to gather more information.

---

If none of the above resolves the issue, please share the exact error message and stack trace for further assistance.

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