Question

In my DB there is View “RqstLst”
I create EF Model from DB. Now I have entity RqstLst.

There is two variant of the same query

public void MyMethod()
{
     context = new WaterMEntities();
     var query = context.RqstLst;
     dgRqstLst.ItemsSource = query;  //dgRqstLst - DataGrid in WPF
}

and

public void MyMethod()
{
    dgRqstLst.ItemsSource = this.GetRqstLst();
}
private IEnumerable<RqstLst> GetRqstLst()
{
        context = new WaterMEntities();
        string nativeSQLQuery = "SELECT  * " +
                                    "FROM dbo.RqstLst ";
        ObjectResult<RqstLst> requestes =
            context.ExecuteStoreQuery<RqstLst>(nativeSQLQuery);
        return requestes;
}

execution time for first variant(LINQ to Entities) is 19 sec, for second, less then 1 sec.
I look it in sql server profiler. What i do wrong in first variant?

Answer 1

One big difference is that ExecuteStoreQuery doesn’t attach the returned objects to the context (at least not the overload you are using) but your first query does (which costs time).

Try to define the same tracking behaviour in your first query like you have in the second query (= NoTracking):

context = new WaterMEntities();
context.RqstLst.MergeOption = MergeOption.NoTracking; // in System.Data.Objects
var query = context.RqstLst;
dgRqstLst.ItemsSource = query;