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From Welly Tambunan <if05...@gmail.com>
Subject Re: Keep Model in Operator instance up to date
Date Wed, 19 Aug 2015 07:49:58 GMT
Hi Gyula,

Thanks.

However update1 and update2 have a different type. Based on my
understanding, i don't think we can use union. How can we handle this one ?

We like to create our event strongly type to get the domain language
captured.


Cheers

On Wed, Aug 19, 2015 at 2:37 PM, Gyula Fóra <gyula.fora@gmail.com> wrote:

> Hey,
>
> One input of your co-flatmap would be model updates and the other input
> would be events to check against the model if I understand correctly.
>
> This means that if your model updates come from more than one stream you
> need to union them into a single stream before connecting them with the
> event stream and applying the coatmap.
>
> DataStream updates1 = ....
> DataStream updates2 = ....
> DataStream events = ....
>
> events.connect(updates1.union(updates2).broadcast()).flatMap(...)
>
> Does this answer your question?
>
> Gyula
>
>
> On Wednesday, August 19, 2015, Welly Tambunan <if05041@gmail.com> wrote:
>
>> Hi Gyula,
>>
>> Thanks for your response.
>>
>> However the model can received multiple event for update. How can we do
>> that with co-flatmap as i can see the connect API only received single
>> datastream ?
>>
>>
>> > ... while external model updates would be tricky to keep consistent.
>> Is that still the case if the Operator treat the external model as
>> read-only ? We create another stream that will update the external model
>> separately.
>>
>> Cheers
>>
>> On Wed, Aug 19, 2015 at 2:05 PM, Gyula Fóra <gyfora@apache.org> wrote:
>>
>>> Hey!
>>>
>>> I think it is safe to say that the best approach in this case is
>>> creating a co-flatmap that will receive updates on one input. The events
>>> should probably be broadcasted in this case so you can check in parallel.
>>>
>>> This approach can be used effectively with Flink's checkpoint mechanism,
>>> while external model updates would be tricky to keep consistent.
>>>
>>> Cheers,
>>> Gyula
>>>
>>>
>>>
>>>
>>> On Wed, Aug 19, 2015 at 8:44 AM Welly Tambunan <if05041@gmail.com>
>>> wrote:
>>>
>>>> Hi All,
>>>>
>>>> We have a streaming computation that required to validate the data
>>>> stream against the model provided by the user.
>>>>
>>>> Right now what I have done is to load the model into flink operator and
>>>> then validate against it. However the model can be updated and changed
>>>> frequently. Fortunately we always publish this event to RabbitMQ.
>>>>
>>>> I think we can
>>>>
>>>>
>>>>    1. Create RabbitMq listener for model changed event from inside the
>>>>    operator, then update the model if event arrived.
>>>>
>>>>    But i think this will create race condition if not handle correctly
>>>>    and it seems odd to keep this
>>>>
>>>>    2. We can move the model into external in external memory cache
>>>>    storage and keep the model up to date using flink. So the operator will
>>>>    retrieve that from memory cache
>>>>
>>>>    3. Create two stream and using co operator for managing the shared
>>>>    state.
>>>>
>>>>
>>>> What is your suggestion on keeping the state up to date from external
>>>> event ? Is there some kind of best practice for maintaining model up to
>>>> date on streaming operator ?
>>>>
>>>> Thanks a lot
>>>>
>>>>
>>>> Cheers
>>>>
>>>>
>>>> --
>>>> Welly Tambunan
>>>> Triplelands
>>>>
>>>> http://weltam.wordpress.com
>>>> http://www.triplelands.com <http://www.triplelands.com/blog/>
>>>>
>>>
>>
>>
>> --
>> Welly Tambunan
>> Triplelands
>>
>> http://weltam.wordpress.com
>> http://www.triplelands.com <http://www.triplelands.com/blog/>
>>
>


-- 
Welly Tambunan
Triplelands

http://weltam.wordpress.com
http://www.triplelands.com <http://www.triplelands.com/blog/>

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