[DGD] Clones and very large arrays

[Robert Forshaw]

>From: Bart van Leeuwen <bart at wotf.org>
>Hmm, you obviously never had 'rogue' clones out there, ie, somethign ended
>up making a zilion clones of an object due to some bug..

Perhaps that's why lightweight objects were mentioned...

>
>Basicly, when you run a persistent mud, keepign track of which objects are
>loaded, and which clones they have is the only possible way to not end up
>with lots and lots of junk that will never be needed again, or at least
>gives you a way to find and remove such junk.
>
>Then, it is quite nice to be able to do something like
>query_clones(obj)->function(args);

Hmm! That looks like you're trying to call a function in an array. ; ) But I 
know what you mean.

> > I didn't understand that, the example you gave is rather ambigious and 
>seems
> > to be suggesting that I store an array of clones referenced by a clone!
> > Surely I want it referenced by a master?
>
>The basic issue is this:
>You store an array of 20000 clones in the master, which means that when
>the master gets swapped out, DGD has to swap out that entire array as
>well.

Sounds like quite a significant performance problem. However, storing the 
array in an object daemon as so:

clone[a_master_object] = ({ some_clones })

Eliminates this swapping problem, doesn't it? And this is how I was doing it 
to begin with! That just leaves me with the array size issue. I'd still like 
to hear whether the idea of making arrays of clones within arrays would 
solve this problem (or even make matters worse), since I've never seen that 
done or seen it suggested before. It would certainly prevent the array size 
limit from being hit as easily (32767 x 32767 = 1073676289), that's a few 
billion or so.


>That said.. in ancient lpmuds, such a linked list was used for example for
>keeping track of pieces of equipment that a player was 'wearing'.

The good old days sucked did they not? : )

>This
>solution caused many bugs due to chains being broken and replacing it by
>an array or mapping (in the player object) makes quite a difference in
>reliability.
>
>Basicly, the problem with chains is that they have a tendency to break and
>that you are kinda lost when they do.

Chain breakage should never happen though if you implement the linked list 
properly?

>
>That is why I am using arrays instead of a linked list (besides the fact
>that an array allows me to call a function in all clones easily)
>
>Trying to increase max array size to sizeof(long)/2 doesn't sound like a
>good plan to me however.. I am not sure (and Felix pls correct me if I am
>wrong) but it might well be that there are places where an array might be
>indexed using an int instead of a long. Makign the max size bigger then
>32767 might result in some subtle and interesting bugs due to that.

I'd like to hear from Felix whether it is possible then. I imagine though 
that even if it were possible, super-big arrays would create a performance 
hit when trying to manipulate it, like in my previous example, deleting an 
element containing particular data.

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