Quoting Marc Dzaebel <mdzaebel(a)web.de>:
Hi Kris,
thanks for your thorough and quite helpful explanation!
Kris Verlaenen wrote:
>
> ... concrete plans in adding separate persistence of process
instance
> variables in the database. I expect this to be added to trunk in a
few
> weeks time.
>
So it could be in in Drools 5.0? I think the different strategies
for
process variables are exactly what we'll need. I'm glad to hear that
standard use cases will be supported soon.
Probably not, Drools 5.0 is feature complete and should be released any
time now. But we're planning to do much more smaller, incremental
releases now, so Drools 5.1 shouldn't be too long.
Kris Verlaenen wrote:
>
> Another strategy ... is not querying on the runtime database but
getting
> the information from the history logs ... Notice that a history log
is not
> only about completed process instances, but about currently
executing ones
> as well. The advantage of this approach is that queries on the
history
> log won't ever
> impact your running sessions and you can define what data to store
> yourself
> (and how), optimized to your use case.
>
This is a quite innovative idea and it sounds logical to reuse
historical
data and gain the aibility to save and query your data appropriately.
It
might slow down db access as you'll have to select the lastest
version of an
instance in advance (might be achieved by a simple flag). May be the
combination of out-of-the-box process/variable persistence and
customized
historical persistence promisses the most benefit. However, we should
work
out patterns/examples of how to persist searchable processes.
Agreed, it does not work for all use cases of course. Not sure what you
mean by "select the latest version of an instance" though, as there is
always only one version of a specific process instance (even in the
history log). Note that the model of the history information is
different from the runtime model, and contains all the nodes that were
triggered (and possibly completed). So new data gets added to this
process instance log every time something new happens, there's no
different versions there.
Kris
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