RE: Overhead and Best Practices

Mark Proctor wrote:
> So even after the work with WeakIdentityMap it will still be 
> orders of magnitudes slower than if we coded natively in C# - 
> or just orders of magnitudes slower than Java?

The difference between C# and Java is only on the order of a factor of
two (probably much less), but IKVM exception handling will remain orders
of magnitude slower (in most cases).

> The dynamic Class Loading and GC is worrying. In Drools 3.0 
> we can add and remove rules; each rule dynamically compiles 
> code. I'm not entirely sure what unloading the entire app 
> domain means.

An AppDomain is essentially a lightweight process (of which you can have
multiple inside a real process). They are completely isolated from each
other (they communicate via remoting (which is something like RMI)).

> In Drools a package has one or more rules, each 
> package has its own dynamic ClassLoader; when a rule is 
> removed or updated we drop and reload the ClassLoader. If we 
> can't hack that to work, we might have to look at a native 
> port after all :(

Note that this code unloading thing is a .NET limitation (although .NET
2.0 can unload methods that are dynamically generated, it cannot unload
dynamically generated classes), so you will also have to deal with this
if you do a native port.

Regards,
Jeroen


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