How to optimize XPO performance

Hello Sergey,

Thank you for contacting us. Would you please describe the issue in greater detail? The method you mentioned was implemented this way on purpose, and we need to know the problem in every detail to suggest an appropriate solution.

So, describe what task you wish to accomplish using the methods of your application demonstrated in the screenshot. Why do you want to accelerate the performance of these methods? Are you researching ways to optimize your code or did your users face a performance issue related to these methods?

Hello Uriah,
We have method which processes big data. This method takes approximately 2 hours, so we want to accelerate the performance of these methods. We are researching ways to optimize our code. We profiled our method, and saw, that DevExpress.Xpo.XpBaseCollection.FilterList  takes 70% of all time. Method DevExpress.Xpo.XpoBaseCollection.FilterList create function for filtering list, and then call created function for each element from list.
But method DevExpress.Xpo.XpoBaseCollection.FilterList creates function also if list is empty. Creating function takes 90% of time of DevExpress.Xpo.XpoBaseCollection.FilterList work.
We attached a simple solution, which can demonstrate bad performance when we iterate list without elements.

C#
internal class A : XPObject  
{  
      private B _b;  
      public A(Session session) : base(session)  
      {  

      }  

      [Association("a-b"), NoForeignKey]  
      public B B  
      {  
            get { return _b; }  
            set { SetPropertyValue("B", ref _b, value); }  
      }  
}  

internal class B : XPObject  
{  
      public B(Session session) : base(session)  
      {  

      }  

      [Association("a-b"), Delayed, NoForeignKey]  
      public XPCollection<A> As { get { return GetCollection<A>("As"); } }  
}  

static void Main(string[] args)  
{  
      XpoDefault.DataLayer =  
                   XpoDefault.GetDataLayer(  
                          @"Data Source=.;Initial Catalog=perf;Integrated Security=True;Connect Timeout=15;Encrypt=False;TrustServerCertificate=False",  
                          AutoCreateOption.DatabaseAndSchema);  

      using (var uow = new UnitOfWork())  
      {  
            for (int i = 0; i < 100000; i++)  
            {  
                   var b = new B(uow);  
                   b.Oid = i;  
                   b.Save();  

                   if (i%10000 == 0)  
                   {  
                          Console.WriteLine(i);  
                   }  
            }  

            uow.CommitChanges();  
      }  

      using (var uow = new UnitOfWork())  
      {  
            var coll = new XPQuery<B>(uow).ToList();  

            uow.PreFetch(coll, "As");  

            //start profiling  
            foreach (var item in coll)  
            {  
                   //FilterList takes 92% of time  
                   foreach (var a in item.As)  
                          Console.WriteLine(a.Oid);  
            }  
            //end profiling  
      }  
}  

Hello Sergey,

Thank you for the example. We can optimize the prefetch operation for the collection members of associations, and this improvement will indirectly improve the situation you described. However, this improvement will be added in version 15.1.8. We could not find the capability to add the corresponding changes to earlier versions. If you are fine with upgrading to version 15.1.8, I can provide you the link to the intermediate build for testing.

Hello Uriah,
Thanks for answer. We can update to version 15.1.8. Waiting fo the link…

Hello Sergey,

The intermediate build will be prepared in a few days. I will post a comment with the download link when it is ready.

Hello Sergey,

Use this link to download the intermediate build containing required changes: DevExpressComponents-15.1.7.15288.exe. As usual, we greatly appreciate your feedback.