How to catch SQLServer timeout exceptions


Question

I need to specifically catch SQL server timeout exceptions so that they can be handled differently. I know I could catch the SqlException and then check if the message string Contains "Timeout" but was wondering if there is a better way to do it?

try
{
    //some code
}
catch (SqlException ex)
{

    if (ex.Message.Contains("Timeout"))
    {
         //handle timeout
    }
    else
    {
         throw;
    }
}
1
110
8/27/2008 7:18:54 AM

Accepted Answer

To check for a timeout, I believe you check the value of ex.Number. If it is -2, then you have a timeout situation.

-2 is the error code for timeout, returned from DBNETLIB, the MDAC driver for SQL Server. This can be seen by downloading Reflector, and looking under System.Data.SqlClient.TdsEnums for TIMEOUT_EXPIRED.

Your code would read:

if (ex.Number == -2)
{
     //handle timeout
}

Code to demonstrate failure:

try
{
    SqlConnection sql = new SqlConnection(@"Network Library=DBMSSOCN;Data Source=YourServer,1433;Initial Catalog=YourDB;Integrated Security=SSPI;");
    sql.Open();

    SqlCommand cmd = sql.CreateCommand();
    cmd.CommandText = "DECLARE @i int WHILE EXISTS (SELECT 1 from sysobjects) BEGIN SELECT @i = 1 END";
    cmd.ExecuteNonQuery(); // This line will timeout.

    cmd.Dispose();
    sql.Close();
}
catch (SqlException ex)
{
    if (ex.Number == -2) {
        Console.WriteLine ("Timeout occurred");
    }
}
149
9/26/2016 4:37:06 PM

here: http://www.tech-archive.net/Archive/DotNet/microsoft.public.dotnet.framework.adonet/2006-10/msg00064.html

You can read also that Thomas Weingartner wrote:

Timeout: SqlException.Number == -2 (This is an ADO.NET error code)
General Network Error: SqlException.Number == 11
Deadlock: SqlException.Number == 1205 (This is an SQL Server error code)

...

We handle the "General Network Error" as a timeout exception too. It only occurs under rare circumstances e.g. when your update/insert/delete query will raise a long running trigger.


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