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From Gyula Fóra <gyf...@apache.org>
Subject Re: Clear irrelevant state values
Date Mon, 25 Apr 2016 09:36:36 GMT

(a) I think your understanding is correct, one consideration might be that
if you are always sending the state to the sink, it might make sense to
build it there directly using a RichSinkFunction.

(b) There is no built-in support for this at the moment. What you can do
yourself is to generate removal markers for the patients automatically. We
could probably add this feature later which might be easier to implement
for some state backends. For instance in RocksDB we could use a
time-to-live database to remove states after a given period.


Sowmya Vallabhajosyula <sowmya.v@zemosolabs.com> ezt írta (időpont: 2016.
ápr. 25., H, 11:22):

> Hi,
> Scenario: Health care where a list of patient events are flowing in. We
> would like to keep a Value / List state holding all events and updating the
> state based on a set of business rules. For e.g. if 4 vitals exceed range
> in 24 hours, state is sirs. If the patient is in sirs state and a source of
> infection is reported now, update state to sepsis. Attached flow for your
> reference.
> Considering the example of RideSource, if I use a RichFlatMapFunction to
> maintain this state (please let me know if this doesn't make sense),
> (a) out.collect will return the current patient state to a sink so at the
> end of every event, we know the state of the patient at this instance. Is
> my understanding right?
> (b) Let's say after x days, these events that we recorded are not valid
> anymore. How do we clear the state?
> --
> Thanks and Regards,
> Sowmya Vallabhajosyula

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