Is NHibernate faster than a classic ODBC Driver?

Question

I am working on an application with a kinda simple data model (4 tables including two small, having around 10 rows, and two bigger, having hundreds of rows). I'm working with C# and currently use an OdbcDriver for my Data Access Layer. I was wondering if there is any difference in terms of performance between this driver or NHibernate? The application works but I'd like to know if installing NHibernate instead of a classic OdbcDriver would make it faster? If so, is the difference really worth installing NHibernate? (according to the fact that I have never used such technology)

Thanks!

Answer 1

Short answer: no, NHibernate will actually slow your performance in most cases.

Longer answer: NHibernate uses the basic ADO.NET drivers, including OdbcConnection (if there's nothing better), to perform the actual SQL queries. On top of that, it is using no small amount of reflection to digest queries into SQL, and to turn SQL results into lists of objects. This extra layer, as flexible and powerful as it is, is going to perform more slowly than a hard-coded "firehose" solution based on a DataReader.

Where NHibernate may get you the APPEARANCE of faster performance is in "lazy-loading". Say you have a list of People, who each have a list of PhoneNumbers. You are retrieving People from the database, just to get their names. A naive DataReader-based implementation may involve calling a stored procedure for the People that includes a join to their PhoneNumbers, which you don't need in this case. Instead, NHibernate will retrieve only People, and set a "proxy" into the reference to the list of PhoneNumbers; when the list needs to be evaluated, the proxy object will perform another call. If the phone number is never needed, the proxy is never evaluated, saving you the trouble of pulling phone numbers you don't need.

Answer 2

NHibernate isn't about making it faster and it'll alwasy be slower than just using the database primatives like you are (it uses them "under the hood").

In my opinion NHibernate about making a reusable entity layer that can be applied to different applications or at the very least reused in multiple areas in one medium to large application. Therefore moving your application to NHibernate would be a waste of time (it sounds very small).

You might get better performance by using a specific datbase driver for your database engine.