Hi All,
I have been evaluating the performance of NHibernate and ADO.NET. I
have created a test application which has an Employee table with
75,000 records. When I try to get data using NHibernate it is very
slow compare to ADO.NET, it’s about 290% (approx.) slower.
The average performance of NHibernate to bind 75,000 records is 2535
milliseconds .
The average performance of ADO.net to bind 75,000 records is 867
milliseconds.
I can understand that NHibernate is a Wrapper to ADO.NET but you
cannot pay the price of 300% for retrieval
We tried the optimization tips for NHibernate from Internet. Here are
some
1) Use of Stateless Session
2) Use of Named Query
3) Session Flushing
4) Using Stored Procedure
5) Using Recompiled option
As per my experience time is getting consumed when building the
objects in memory .Also the query which is getting fired from
NHibernate and SQL in Profiler has differences. Does not make any
difference if executed again and again .
Query Executed in SQL Manually :
Select ID, Name, DateOfJoin, DateOfBirth, DepartmentID, Status from
Employee : Duration 516
Query Executed in SQL by NHibernate :
Select this._ID as ID2_0_, this_.Name as Name2_0_, this_.DateOfJoin as
DateOfJoin2_0_, this_.DateOfBirth as DateOfBirth2_0_,
this_.DepartmentID as DepartmentID2_0_, this_.Status as Status2_0_
from dbo.Employee this_: Duration 1538
Kindly suggest any other mechanism for increasing the performance.
What should be the ideal performance difference when using ORM?
Please find the code below….
//Employee Class
public class Employee
{
public virtual int ID { get; set; }
public virtual string Name { get; set; }
public virtual DateTime DateOfJoin { get; set; }
public virtual DateTime DateOfBirth { get; set; }
public virtual string DepartmentID { get; set; }
public virtual string Status { get; set; }
}
//NHibernate Mapping
public EmployeeMap()
{
Table("Employee");
Id(p => p.ID).GeneratedBy.Increment();
Map(p => p. Name);
Map(p => p. DateOfJoin);
Map(p => p. DateOfBirth);
Map(p => p. DepartmentID);
Map(p => p. Status);
}
//Building Session Factory
public static ISessionFactory SessionFactory
{
get
{
if (_sessionFactory == null)
{
_sessionFactory = Fluently.Configure()
.Database(MsSqlConfiguration.MsSql2008.ConnectionString(c
=> c.FromConnectionStringWithKey("Connection")))
.Mappings(m =>
m.FluentMappings.AddFromAssemblyOf<Employee>())
.BuildSessionFactory();
}
return _sessionFactory;
}
}
//Fetching data using CreateQuey
using (IStatelessSession session =
SessionManager.SessionFactory.OpenStatelessSession())
{
IList<Employee> lstEmployee = session.CreateCriteria<
Employee >().List<Employee>();
return lstEmployees.ToList<Employee>();
}
//Fetching data using Create Query
using (IStatelessSession session =
SessionManager.SessionFactory.OpenStatelessSession())
{
IList<Employee> lstEmployee =
session.CreateQuery("from Employee ").
List<Employee>();
return lstEmployees.ToList<Employee>();
}
//Fetching Data using ADO.net
DataTable dtEmployees = /*Data is fetched from ADO.net using SQL
Query*/;
List<Employee> lstEmployee = new List<Employee>();
foreach (DataRow dr in dtEmployees.AsEnumerable())
{
Employee employee = new Employee
{
ID = dr.Field<int>("ID"),
Name = dr.Field<decimal>("Name"),
DateOfJoin = dr.Field<int>("DateOfJoin"),
DateOfBirth = dr.Field<int>("DateOfBirth"),
DepartmentID = dr.Field<int>("DepartmentID"),
Status = dr.Field<DateTime>("Status"),
};
lstEmployee.Add(Employee);
}
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