whether ASP.Net Profile Provider's GetPropertyValue() is per request method or per session method?

Question

I like to know, when will the GetPropertyValue() Method called?

I have written a proxy pattern for sql profile provider and i tried using the profile properties in my application.

I tried both authenticated and anonymous user mode, when ever the profile property values are accessed, profileProvider GetPropertyValue() method is called and it is hitting the DB to fetch the values.

I like to know, when will the profile values presist in the context?

For each & every request, I m seeing the profileProvider is called to fetch the values. If so, then what is use of having Profile in HttpContext.Current?