flink-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Robert Metzger <rmetz...@apache.org>
Subject Fwd: [stratosphere-dev] Grouping by a tuple
Date Wed, 11 Jun 2014 22:25:06 GMT
Hi Slava,

I'm forwarding your message to our new mailing list at Apache:
dev@flink.incubator.apache.org
You can subscribe to the list by sending an (empty) email to:
dev-subscribe@flink.incubator.apache.org.
We are planning to shut down the stratosphere-dev@googlegroups soon.

Regarding your question: When using the Tuples, you don't need to specify a
keySelector. It is sufficient to specify the ID(s) of the keys:
http://stratosphere-javadocs.github.io/eu/stratosphere/api/java/DataSet.html#groupBy(int..
.)
So you should be able to do a ".groupBy(0,3,4)"

Robert

---------- Forwarded message ----------
From: Vyacheslav Zholudev <vyacheslav.zholudev@gmail.com>
Date: Thu, Jun 12, 2014 at 12:17 AM
Subject: [stratosphere-dev] Grouping by a tuple
To: stratosphere-dev@googlegroups.com


Hi,

Being used to the Hive grouping like "GROUP BY userId, productId, year" I'm
wondering what's the best way to do it in Stratosphere? The groupBy's
KeySelector implies that a Comparable object is returned, however, the
obvious choice like TupleN is not comparable. In primitive cases I would
prefer to avoid introducing comparable extra entities for grouping tuples
of "primitive" types. Would it make sense to introduce "ComparableTupleN<T1
extends Comparable<? extends T1>, ..., Tn extends Comparable<? extends
Tn>>"?

Or am I missing the obvious way in a Stratosphere way?

Thanks,
Vyacheslav

-- 
You received this message because you are subscribed to the Google Groups
"stratosphere-dev" group.
To unsubscribe from this group and stop receiving emails from it, send an
email to stratosphere-dev+unsubscribe@googlegroups.com.
Visit this group at http://groups.google.com/group/stratosphere-dev.
For more options, visit https://groups.google.com/d/optout.

Mime
  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message