Как можно ускорить работу данной програмы с базой?

var yml =
    from y in DC.tblCompetitorYMLs
    select y;
 
SqlConnection conn =
    new SqlConnection(
    ConfigurationManager.
    ConnectionStrings["StockPriceCorrectionCompetitorsBased.Properties.Settings.zoneConnectionString"].
    ConnectionString);
 
int cnt = 0;
SqlDataAdapter sda = new SqlDataAdapter("", conn);
conn.Open();
 
foreach (var yml_entry in yml)
{
    if (yml_entry.ISBN == null)
    {
        continue;
    }
    string[] isbn_collection =
        yml_entry.ISBN.ToUpper().Replace("-", "").Split(',');
    sda.SelectCommand.CommandText = string.Format(@"
        SELECT c.cat_id FROM catalog c
        INNER JOIN tblBookIsbn i ON c.cat_id = i.cat_id
        WHERE REPLACE(UPPER(bi_Name), '-', '') in ('{0}');",
        string.Join("','", isbn_collection));
    DataTable dt = new DataTable();
    sda.Fill(dt);
    foreach (DataRow r in dt.Rows)
    {
        tblCompetitorPrice cp = new tblCompetitorPrice();
        cp.competitor_id = competitor_id;
        cp.competitor_item_id = Convert.ToInt32(yml_entry.id);
        cp.price = Convert.ToDecimal(yml_entry.price);
        cp.cat_id = Convert.ToInt32(r["cat_id"]);
        DC.tblCompetitorPrices.InsertOnSubmit(cp);
    }
    if (cnt++ % 1024 == 0)
    {
        logger.Trace("Обработано " + cnt);
    }
}
conn.Close();
DC.SubmitChanges();