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;
    }
}

Answer 1

Whats the value for the SqlException.ErrorCode property? Can you work with that?

Seems like this guy is having timeouts, may be worth checking the code for -2146232060.

I would set this up as a static const in your data code.

Answer 2

I searched through our error log files for previous occurrences of ErrorCode -2146232060 and found several instances where it does not relate to a timeout error. The error code also occurs for data conversion errors and deadlock errors.

I noticed that the exception provides another 'Number' field which seems to always be set to '2' for timeout errors. I guess I'll just check both the ErrorCode and Number properties rather than do a Contains("Timeout") on the Message property.

But I can't find any documentation out there about these magic numbers ... if anyone has a link it'd be appreciated.

Answer 3

Are you looking for a ConnectionTimeout or a CommandTimeout, ie are you expecting the connection to fail or the executed command to fail?

Answer 4

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");
}