Linq compiled query and performance issue

Question

I am having some performance issue of linq compiled query.

using (var txn = new TransactionScope(TransactionScopeOption.Required, new TransactionOptions { IsolationLevel = System.Transactions.IsolationLevel.ReadUncommitted }))
        {
            DateTime dealcheck = new DateTime(1753, 2, 2);

            Func<DealDataClassesDataContext, string, IQueryable<DealsDetails>> DD =
            CompiledQuery.Compile<DealDataClassesDataContext, string, IQueryable<DealsDetails>>

    ((DealDataClassesDataContext nw, string sCity) =>

        from D in nw.Deals

        where D.Address == City && (D.DealTime >= DateTime.Now || D.DealTime == dealcheck) && PriceMax >= D.DealPrice && D.DealPrice >= PriceMin && DisCountMax >= D.SavingsRate && D.SavingsRate >= DiscountMin && (D.DealTime >= DateTime.Now.AddDays(TimeMin) && D.DealTime <= DateTime.Now.AddDays(TimeMax) || D.DealTime == dealcheck)

        select new DealsDetails(
                          lst,
                          D.DealId,
                          D.DealHeadline,
                          D.DealCategory,
                          D.BuyPrice,
                          D.DealPrice,
                          D.SavingsRate,
                          D.SavingAmount,
                          D.RelatedWebsite,
                          D.Address,
                          string.Empty,
                          D.DealImage,
                          string.Empty,
                          string.Empty,
                          D.Time, D.CurrentTime, D.DealTime,
                         D.Location, string.Empty, string.Empty, D.Latitude, D.Longitude, D.Islocal, D.VendorMail, D.MerchantInfo, D.Review, D.HowItWork, D.DealUrl
                          ));

            string jString = "";

            //int a = q(DealDbContext1, "London").Count();

            using (DealDataClassesDataContext db = new DealDataClassesDataContext())
            {
                IQueryable<DealsDetails> DDD = DD.Invoke(DealDbContext, "London");

                if (lstSite.Count > 0 && lstSite[0] != "AllDeals")
                {
                    DDD = DDD.Where(D => D.RelatedWebsite.Split(',').Where(x => lstSite.Contains(x)).Any()); //.Where(row => row.Category.ToList().Where(x => lst.Contains(x)).Any()).ToList();
                }
                if (lst.Count > 0)
                {
                    DDD = DDD.Where(D => D.Categories.Split(',').Where(x => lst.Contains(x)).Any()); //.Where(row => row.Category.ToList().Where(x => lst.Contains(x)).Any()).ToList();
                }
                if (sortby == "Time" && orderby == "Asc")
                {
                    DDD = (from d in DDD orderby d.Time ascending select d).Skip((Page - 1) * PageSize).Take(PageSize);
                }
                else if (sortby == "Time" && orderby == "Desc")
                {
                    DDD = (from d in DDD orderby d.Time descending select d).Skip((Page - 1) * PageSize).Take(PageSize);
                }
                else if (sortby == "Price" && orderby == "Asc")
                {
                    DDD = (from d in DDD orderby d.DealPrice ascending select d).Skip((Page - 1) * PageSize).Take(PageSize);
                }
                else if (sortby == "Price" && orderby == "Desc")
                {
                    DDD = (from d in DDD orderby d.DealPrice descending select d).Skip((Page - 1) * PageSize).Take(PageSize);
                }
                else if (sortby == "Percent" && orderby == "Asc")
                {
                    DDD = (from d in DDD orderby d.SavingsRate ascending select d).Skip((Page - 1) * PageSize).Take(PageSize);
                }
                else if (sortby == "Percent" && orderby == "Desc")
                {
                    DDD = (from d in DDD orderby d.SavingsRate descending select d).Skip((Page - 1) * PageSize).Take(PageSize);
                }
                else
                {
                    DDD = DDD.Skip((Page - 1) * PageSize).Take(PageSize);
                }

                string Currency = "$";
                foreach (DealsDetails item in DDD)
                {
                    //Creating Html String Here
                }

                return jString;

I have attached My whole code here please check what is the issue with this it's taking too long time to respond arround 20 sec.

Mainly the foreach loop takng more then 17 sec.

Please let me know how do I compile this query.

Thanks in Advance.

Answer 1

In addition to pre-compiling your query, you should pre-generate the local query views