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From Ufuk Celebi <...@apache.org>
Subject Re: Future of Queryable State Feature
Date Mon, 20 Mar 2017 14:49:32 GMT
On Mon, Mar 20, 2017 at 3:25 PM, Aljoscha Krettek <aljoscha@apache.org> wrote:
> I think adding this could be as simple as adding a makeWindowContentsQueryable(String)
call to WindowedStream. In there, we create the StateDescriptor for keeping the window contents
so we can call setQueryable() on the StateDescriptor and set the name under which it should
be accessible. If you want you can create an issue and change this. I can help you if you
have any questions.


I would only allow this for incrementally aggregating windows in the
first version (reduce, fold, etc.). Does this make sense for your use
case Joe? Otherwise, the state might grow quite large and for session
windows identifying the session is quite tricky. We only need to watch
out for the fast path implementation (using
AbstractAlignedProcessingTimeWindowOperator) that cannot be queried.

If you would like to work on this, I would also be happy to work with
you and create the initial JIRA writing down things that we should
watch out for.

– Ufuk

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