Question

I have an issue on a codebit with an ASP.NET Webforms 4 application.
I am using SQL server 2008 R2, IIS 7, the website is running on Windows Server 2008 R2 in separate Application pool (integrated mode, .NET4, with support for 32bit assemblies).

The following code is posing problems:

Dim sqlCmd = New SqlClient.SqlCommand
With sqlCmd
    Using sqlConnectionToUse As SqlClient.SqlConnection = GetActiveConnexion(pstrConnectString), _
        vAdaptor As New SqlClient.SqlDataAdapter

            .Connection = sqlConnectionToUse

            .CommandText = pstrSQL 'function parameter

            vAdaptor.SelectCommand = sqlCmd
            'query1: SELECT somecolumn FROM table WHERE somecolumn '' ==> opens a new connection in SQL Server
            'query2: SELECT someothercolumn FROM anothertable WHERE someothercolumn 23 ==> uses my WebSite process active connection
            vAdaptor.Fill(vDataSet)
    End Using
End With

UPDATE: the GetActiveConnexion() method simply does the following code in my case:

Return New SqlClient.SqlConnection("my connection string obtained from the web.config file")

When I run the query2, everything goes smoothly, the ASP.NET application uses the openned connection of the application pool and I get my results in the dataset.

However, whenever I run the query1, a NEW connection is openned in SQL server (I can see it show up in the SSMS’s Activity Monitor) and this one remains openned. The problem is that If I run this query1 100 times, I reach the connection pool’s limit and very bad things happens. I still gets the results in the dataset, can use them etc…
The new connection is created on the call of vAdaptator.Fill().

Any idea on what’s wrong ?

Thanks a lot for your time.
(PS: sorry for the bad english).

Here is the code in C# for those who prefer:

object sqlCmd = new SqlClient.SqlCommand();
using (SqlClient.SqlConnection sqlConnectionToUse = GetActiveConnexion(pstrConnectString)) {
    using (SqlClient.SqlDataAdapter vAdaptor = new SqlClient.SqlDataAdapter()) {

        sqlCmd.Connection = sqlConnectionToUse;

        sqlCmd.CommandText = pstrSQL; //function parameter

        vAdaptor.SelectCommand = sqlCmd;
        //query1: SELECT F10_ID FROM FIN_MONTANT_TT_F10 WHERE F10_ID_TT_F19 = '' ==> opens a new connection in SQL Server
        //query2: SELECT A48_ID FROM ADH_EPARTICIPANT_ADMIN_A48 WHERE A48_ID=23 ==> uses my WebSite process active connection
        vAdaptor.Fill(vDataSet);
    }
}

Answer 1

Your SqlCommand instance should be wrapped in a using block as it’s Disposable. It’s probably the source of your problems.

using (SqlClient.SqlConnection sqlConnectionToUse = GetActiveConnexion(pstrConnectString)) 
{
    using (SqlCommand sqlCmd = sqlConnectionToUse.CreateCommand())
    {
        using (SqlClient.SqlDataAdapter vAdaptor = new SqlClient.SqlDataAdapter()) 
        {
            ...
        }
    }
}

Or VB

Using sqlConnectionToUse As SqlClient.SqlConnection = GetActiveConnexion(pstrConnectString)
    Using sqlCmd As SqlCommand = sqlConnectionToUse.CreateCommand()
        Using vAdaptor As New SqlClient.SqlDataAdapter()
                ...
        End Using
    End Using
End Using