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From Aljoscha Krettek <aljos...@apache.org>
Subject Re: Does Flink support joining multiple streams based on event time window now?
Date Tue, 19 Apr 2016 09:32:48 GMT
Hi,
right now, there is no built-in support for n-ary joins. I am working on
this, however.

For now you can simulate n-ary joins by using a tagged union and doing the
join yourself in a WindowFunction. I created a small example that
demonstrates this:
https://gist.github.com/aljoscha/a2a213d90c7c1bc67e71fabaa82fba4a

I hope this helps, and please let us know if you want to know more.

Cheers,
Aljoscha

On Tue, 19 Apr 2016 at 02:11 Yifei Li <lee891031@gmail.com> wrote:

> Hi,
>
> I am new to Flink and I've read some documentation and think Flink may fit
> my scenario.
>
> Here is my scenario:
>
> 1. Assume I have 3 streams: S1(id, name, email, action, date), S2(id,
> name, email, level, date), S3(id, name, position, date).
>
> *2. S2 always delays(hours to days, not determined..) *
>
> 3. Based on the event time, I want to join S1, S2 and S3 every 5 minutes.
> The join is like a SQL join:
>     select S1.name, S3.position from S1, S2, S3 where S1.id = S2.id and
> S1.id = S3.id and S1.action = 'download' and S2.level = 5
>
>
>
> Can I use Flink for my scenario? Is yes, can anyone point me to some
> working examples(I found some examples but they are outdated), or tell me
> some workaround to solve this problem? If no, can anyone tell me the
> reasons?
>
> Thanks,
>
> Yifei
>
>
>
>
>
>

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