I have created a prototype of a custom ORM tool using aspect oriented programming (PostSHarp) and achieving persistence ignorance (before compile-time). Now I tried to find out how much overhead does it introduce compared to using pure DataReader and ADO.NET. I made a test case – insert, read, delete data (about 1000 records) in MS SQL Server 2008 and MySQL Community Edition. I run this test multiple times using pure ADO.NET and my custom tool.
I expected that results will depend on many factors – memory, swapping, CPU, other processes so I ran tests for many times (20-40). But the results were really unexpected. They just differed too much between those cases. If there were just some extreme values, I could ignore them (maybe swapping ocurred or smth. like that) but they were so different that I am sure I cannot trust this kind of testing. Almost half of times my ORM showed 10% better performance than pure ADO.NET, other times it was -10%.
Is there any way I can make those tests reliable? I do not have a powerful computer with lots of memory, but maybe I somehow can make MS SQL and MySQL or ADO.NET to be as consistent as possible during those tests? And how about count of records – which is more reliable, using small amount of records and running more times or other way?
Have you seen ORMBattle.NET? See FAQ there, there are some ideas related to measuring performance overhead introduced by a particular ORM tool. Test suite is open source.
Concerning your results:
peak possible performance here, since in general, RDBMS must do much more than ORM in this case.
P.S. I’m one of ORMBattle.NET authors, so if you’re interested in details / possible contributions, you can contact me directly (or join ORMBattle.NET Google Groups).