Hi guys. I'm rereading CLR via C# right now and have some thoughts about garbage collection routine. In book, after zero generation is filled, garbage collection starts and moves all "not garbage" references to the first generation. The same happens when the first generation is filled. But what happens when second generation is filled? There are no other generations to move references. Is CLR simply makes the second generation bigger?
P.s. Thank you for answers and sorry for my English.
Yes, it will expand the size of Generation 2 if it can. If there is no more space available you will get an OutOfMemoryException.
The different generations of garbage collection are not about having a particular size but about how old the garbage is. None of the generations have size limitations that I know of.
From my understanding, there is only one heap (ironically, it's usually depicted as a stack). Objects are promoted to generation 1 not when generation 0 fills, but when they survive a collection. In brief, references are not "moved," the location used to identify where the generation ends is moved.
When the heap gets close to being full, a few things occur:
Objects that survive collection are then moved to generation 0 (if this is their first collection cycle) or generation 2 (if they have survived more than one collection). This is done for efficiency sake, to ensure that we don't constantly try to collect long-lived objects.
You don't run out of space in generation specific ways. See this article for a good explanation.