How to load values faster from my database

Question

public static IEnumerable<Student> GetStudents()
{
    List<Student> students = (List<Student>)HttpContext.Current.Cache.Get("GetAllStudentWithImg");

    if (students!= null)
    {
        return students ;
    }

    students = new List<Student>();

    using (PrincipalContext context = GetPrincipalContext())
    {
        using (UserPrincipal uprinc = new UserPrincipal(context))
        {
            using (PrincipalSearcher psearcher = new PrincipalSearcher(uprinc))
            {
                students = psearcher.FindAll()
                                    .Select(x => new Student((DirectoryEntry)x.GetUnderlyingObject()))
                                    .ToList(); 
            }
        }
    }

    HttpContext.Current.Cache.Add("GetAllStudentWithImg", students, null, 
                                  DateTime.UtcNow.AddMinutes(60), 
                                  System.Web.Caching.Cache.NoSlidingExpiration,
                                  System.Web.Caching.CacheItemPriority.Normal, null);

    return students;
}

I created this function to get values from my database and it work but it load slowly, the pictures are not that many or big, so its not the content, I wonder if someone want to help me with improving my code?

suggestion,, have two calls to load basic data and image related data.. — Kavindu Dodanduwa, May 07 '16 at 07:28
That's not loading from a *database* - this code is searching **Active Directory**..... question is: ***why*** do you need to get the underlying object? That's a rather expensive call - can you do without that call? — marc_s, May 07 '16 at 08:07
@Lal: `PrincipalContext`, `PrincipalUser` - those are classes in .NET to access and work with **Active Directory** .... — marc_s, May 07 '16 at 14:31
@marc_s Thanks :) , i thought they were just Student, Principal, School classes etc. — lal, May 10 '16 at 07:56

score 1 · Accepted Answer · edited May 07 '16 at 14:31

1

I do not see all your code, the code where you query to the database is not displayed, but I think the problem is here:

psearcher.FindAll().Select( ....

FindAll() returns all records in the database table, after this you select what you need in your collection.

The better performance solution is: to query to the database only what you need.

then do not FIND ALL data, but find only what you need

edited May 07 '16 at 14:31

marc_s

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answered May 07 '16 at 07:24

danilonet

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Actually, he's not filtering at all. In this case he's just using Select to transform the results, not actually to select them. – Paul May 07 '16 at 09:24
Thansk.. that was the one i was looking after, my biggest problem was the photos. – GhostReccon May 10 '16 at 09:14

score 1 · Answer 2 · edited May 23 '17 at 12:23

1

Check this, comparision between findall and where: C# FindAll VS Where Speed.

Beside that, why don't you use inheritance between these PrincipalContext,UserPrincipal and PrincipalSearcher?

edited May 23 '17 at 12:23

Community

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answered May 07 '16 at 10:20

Berkay Yaylacı

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score 0 · Answer 3 · answered May 07 '16 at 15:35

0

FindAll() is not a Linq method. It's List(Of T) method and as such, it does not have Deffered execution as opposed to Where() which is Linq and supports deferred execution.

answered May 07 '16 at 15:35

Mukesh Adhvaryu

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How to load values faster from my database

3 Answers3