Solving a timeout error for SQL query

Question

I am getting this error:

Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding.

I know there are already guides out there to help solve this but they are not working for me. What am I missing or where should I add the code to these SQL statements in my C# program:

String sql = project1.Properties.Resources.myQueryData;

SqlDataAdapter sqlClearQuestDefects = new SqlDataAdapter(sql,
    "Data Source=ab;Initial Catalog=ac;User ID=ad; Password =aa");

DataSet lPlanViewData = new DataSet();
sqlClearQuestDefects.Fill(lPlanViewData, "PlanViewData");

I am getting the timeout error at this line:

SqlDataAdapter sqlClearQuestDefects = new SqlDataAdapter(sql, 
    "Data Source=ab;Initial Catalog=ac;User ID=ad; Password =aa");

Answer 1

SqlDataAdapter adp = new SqlDataAdapter();
adp.SelectCommand.CommandTimeout = 0;  // Set the Time out on the Command Object

Answer 2

You're trying to connect to a SQL Server, and it is taking longer than ADO.NET is willing to wait.

Try connecting to the same server, using the same username and password, using SQL Server Management Studio. If you get the same error, there is either something wrong with your connection string, the server you specify is not running, or you can't get to the server across the network from where you are (maybe you're on a public IP address trying to get in to an internal server name). I can't think of a scenario in which you'd enter the exact same server and credentials into SSMS and connect, then do the same in ADO.NET and fail.

If you're on a slow network, you can try increasing the timeout value. However, if a connection is going to happen at all, it should happen pretty quickly.

Take a look at both your SQL Native Client settings, and the SQL Server settings on the server. There is a section for allowed protocols; SQL can connect using a variety of protocols. Usually, you want TCP/IP for a server on the network, and Named Pipes for a server running on your own computer.

EDIT FROM YOUR COMMENT: Oh, that's normal; happens all the time. From time to time on a TCP network, packets "collide", or are "lost" in transmission. It's a known weakness of packet-switching technologies, which is managed by the TCP protocol itself in most cases. One case in which it isn't easily detected is when the initial request for a connection is lost in the shuffle. In that case, the server doesn't know there was a request, and the client didn't know their request wasn't received. So, all the client can do is give up.

To make your program more robust, all you have to do is expect a failure or two, and simply re-try your request. Here's a basic algorithm to do that:

SqlDataAdapter sqlClearQuestDefects;

short retries = 0;
while(true)
{
    try
    {
       sqlClearQuestDefects = new SqlDataAdapter(sql, "Data Source=ab;Initial Catalog=ac;User ID=ad; Password =aa");
         break;
    }
    catch(Exception)
    {
       retries++;
         //will try a total of three times before giving up
       if(retries >2) throw;    
    }
}

Answer 3

Since the exact command to increase connection time out wasn't mentioned in the other answers (of yet)- if you do determine a need to increase your connection time out, you would do so in your connection string as follows:

 Data Source=ab;Initial Catalog=ac;User ID=ad; Password =aa; Connection Timeout=120

Where 120 = 120 seconds. Default is 20 or 30 as I recall.