forwarding to the new mailing list ... ---------- Forwarded message ---------- From: Fabian Hueske <[email protected]> Date: Wed, Jun 18, 2014 at 11:20 AM Subject: Re: [stratosphere-users] FlatJoin implementation To: "[email protected]" < [email protected]>
Hi Asterios, this mailing list is no longer used. All mails (user + dev) should go to the [email protected] mailing list. To the topic: This feature has been requested by quite a few people. So I think it makes sense to provide this interface (plus joinFilter). The same applies to Cross which is less often used though... A less confusing workaround could be to use join.project() an flatMap. Cheers, Fabian 2014-06-18 11:10 GMT+02:00 Asterios Katsifodimos <[email protected]>: Hi, > > I've noticed that the join implementation supports a collector in the > sense that it can become a "flat" join. > > The result is that we have to implement something like this that is kind > of ugly: > public static final class VertexComponentIDProjectorWithFilter extends > JoinFunction<Tuple2<Long, Long>, Tuple2<Long, Long>, Tuple2<Long, Long>>{ > @Override > public void join(Tuple2<Long, Long> first, Tuple2<Long, Long> second, > Collector<Tuple2<Long, Long>> out) throws Exception { > if(first.f1 < second.f1){ > out.collect(new Tuple2<Long,Long>(first.f0, first.f1)); > } > else{ > out.collect(second); > } > } > > @Override > public Tuple2<Long, Long> join(Tuple2<Long, Long> first, > Tuple2<Long, Long> second) throws Exception { > return null; > } > } > > > A first comment on the above code is that the developer has to provide a > null-returning, non-collector default join function. This makes code ugly > and introduces a confusion: which of the two is going to be actually > executed? Shouldn't there be a "Flatjoin" operator that would be > "semantically correct"? Or would it complicate developer's life? > > Cheers, > Asterios > > -- > You received this message because you are subscribed to the Google Groups > "stratosphere-users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > Visit this group at http://groups.google.com/group/stratosphere-users. > To view this discussion on the web visit > https://groups.google.com/d/msgid/stratosphere-users/7b905c5a-7ec6-4e9d-a284-5b6ae3b0b977%40googlegroups.com > <https://groups.google.com/d/msgid/stratosphere-users/7b905c5a-7ec6-4e9d-a284-5b6ae3b0b977%40googlegroups.com?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "stratosphere-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. Visit this group at http://groups.google.com/group/stratosphere-users. To view this discussion on the web visit https://groups.google.com/d/msgid/stratosphere-users/CAAdrtT2t7iKUbDxswFND9VJKv0sF%3Da1C6s_0Whojo4Bmtv94Vg%40mail.gmail.com <https://groups.google.com/d/msgid/stratosphere-users/CAAdrtT2t7iKUbDxswFND9VJKv0sF%3Da1C6s_0Whojo4Bmtv94Vg%40mail.gmail.com?utm_medium=email&utm_source=footer> . For more options, visit https://groups.google.com/d/optout.
