[rules-users] Determining the active nodeinstance for a process

[Kris Verlaenen]

Quoting Garrett Conaty <garrett at conaty.net>:

> Question on JPAProcessInstanceManager.getProcessInstances.  I see
> that  
> it returns an empty array, which I suppose makes sense otherwise it 
> would load every process instance from the db?
Yes, in that case it doesn't make sense to fetch all instances from db
(performance wise that could be very bad, so you shouldn't do this), so
returning an empty set there.

> What is the recommended strategy for keeping track of active
> processes  
> that need to be loaded into a WorkingMemory for example on
> application  
> startup?  An enhancement perhaps with different named queries through
> JPA or ?
In theory, you shouldn't worry about loading process instances, the
engine should worry for you.  Whenever you send a trigger, it will
determine which instances need to be loaded.

> It would seem that to perform some kind of reporting based on the  
> active nodes, that using the WorkingMemoryDbLogger would be the best 
> (and most inexpensive) choice.  Querying them dynamically has the  
> potential to load them from the db on each query.
If you can do it using the db logger, do it ! If you can't do it, first
consider extending the db logger ;) As that should be the preferred way,
as it doesn't impact runtime performance and shields you from internal
details.

Kris

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