Can using Modules or Shared/Static references to the BLL/DAL improve the performance of an ASP.NET website?
I am working of a site that consists of two projects, one the website, the other a VB.NET class library which acts as a combination of DAL and BLL.
The library is used to communicate with databases and sometimes transform/validate the data going into/coming from the DBs.
Currently each page on the site that needs db access (vast majority) will create an instance of the relevant class in the library to access specific tables.
As I understand it this leads to a class from the library being instantiated and garbage collected for each request, with the possibility of multiple concurrent instances if multiple users view the same page.
If I converted the classes to modules (shared/static class) would performance increase and memory be saved as only one instance of each module exists at a time and a new instance is not having to be created for each request?
(if so, does anyone know if having TableAdapters as global variables in the modules would cause problems due to threading?)
Alternatively would making the references to the Library class it the ASP.NET page have the same effect? (except I would have to re-write a lot less)
I’m no expert, but think that the absence of examples of this static class / session object model in books and online is indicative of it being a bad idea.
I inherited a Linq-To-Sql application where the db contexts were static, and after n requests the whole thing just fell apart. The standard model for L2Sql is the Unit-of-Work pattern (define a task or set of tasks – do them and close). Let the framework worry about connection pooling and efficient GC.
Are you just trying to be efficient or do you have performance issues? If the latter it’s usually more effective to look at caching or improving query efficiency (use stored procedures, root out queries in loops) than looking at object instantiation.
Statics don’t play well with unit tests either (another reason why they have dropped out of fashion).