[infinispan-dev] distributed execution - invoking commands on self

[Vladimir Blagojevic]

Hi,

I discovered a problem with distributed framework in cases where 
Callables submitted for distributed execution contain mutable instance 
fields. Just before Callable is dispersed across cluster it gets invoked 
locally where instance fields of a submitted Callable can be possibly 
mutated; Callable is in turn sent to remote nodes with mutated values 
instead of "original" field values as submitted by user. For example, 
consider pi approximation example from wiki [1]. If CircleTest Callable 
declared insideCircleCount as an instance field instead of local field 
of call method we would ultimately get a wrong final result.

Therefore we need to ensure that each Infinispan node gets an unmodified 
instance of Callable for execution. I was looking at the possibility to 
send command to self thus causing creation of a marshaled copy of a 
Callable, pretty much like any other remote node receives it. However, I 
was unable to invoke a command on self. Any way to do this? How about 
invoking marshaling locally to create a Callable copy without going 
through rpc invocation layer? I though about skipping master/self node 
altogether but that's an easy way out;-)

Got suggestions, ideas?

Regards,
Vladimir


[1] http://community.jboss.org/wiki/InfinispanDistributedExecutionFramework