Dynamic Memory managment

Question

Hi, In our application static class variables are created when application is invoked by a user and these variables are accessed throughout the application, once the user shutdown application dose it get cleared from the memory by GC Note: Application refers to Web application developed using asp.net and c#.net.

Kailash Chandra Behera · Answer

Hi Karthik, Static methods are not objects that are subject to garbage collection, so they have no lifetime issues for you to deal with. For each static field there is one copy per-appdomain - each appdomain can have a different value. The static variable itself is not garbage collected - it is just a memory location that contains a reference to an object. Static fields are considered to be GC roots, so any references in them will not be garbage collected as long as the field contains that reference. If you change the field to point to a new reference or set the field value to null then the object whose reference was stored there becomes eligible for collection. Static class constructors will run once for each appdomain they get loaded in. Per your example, the method AddItem() is not an object that can get garbage collected, it is a method. Each time you call AddItem a new Collection object will be allocated and its reference assigned to the field coll. Any previous reference stored in that field will be eligible for garbage collection, but the current reference will not be GCd. Kindly mark as answer, if it helps you Regards, Kailash

Vulpes · Answer

You really need advice on a question such as that from someone who has experience of building such a large site which, as someone who's mainly a desktop developer, I don't have. I'd repost the question to a new thread.

Karthik Puppala · Answer

Hi Vulpes, As per our application build so far it is required to hold the large amount of data on server side and need to wait for end user approval to transfer data to data base, not only this as well as to bind the data to gridview on page change or filtering data displayed on grid i need to hold the data Please let me know what can improve site performance, and reduce the number of data base hits per user. Note: Our application is very huge and my self involved in development of this application since past 4 year's and thousands of end users are using this application on this date. Please suggest.

Vulpes · Answer

Well, I certainly wouldn't use view state or any other client-side state management options for storing anything other than a small amount of data. Static variables are a server-side state management option and will persist for as long as the web application runs. In fact using static variables is akin to using Application state and I think I read somewhere that MS actually recommend that you use the former as they are quicker to access than Application state. However, again, Application state is not usually recommended for storing large amounts of data. Do you actually need to store the DataSet on the server or could you just retrieve information from the database as and when needed?

Karthik Puppala · Answer

As the application is web application and end user's instead of signing out application, they might close the web browser, what happens then to the memory claimed by the static variables. weather the static variables are initialized at page level, dose they get destroyed when page is not in use(like view state) My idea behind this to use static variables instead of view state's to hold huge amount of data like DataSet in ADO.net Please suggest.

Vulpes · Answer

When a process ends, the memory and any other resources it was using are reclaimed by the operating system. Consequently, any static fields which still refer to objects when a .NET application ends will automatically have their memory reclaimed.