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Posted to dev@flink.apache.org by Timo Walther <tw...@apache.org> on 2015/02/04 14:38:43 UTC
Sorting of fields
Hey,
is it correct that we currently do not support sorting without any
grouping? I had this question by 2 users in the last weeks and now I
also need this functionality.
Is it possible to sort e.g. a word count result Tuple2<String, Integer>
by count?
Regards,
Timo
Re: Sorting of fields
Posted by Stephan Ewen <se...@apache.org>.
Based on this, we should also be able to implement a global top-k, which
has come up as a frequent requirement.
On Wed, Feb 4, 2015 at 2:55 PM, Fabian Hueske <fh...@gmail.com> wrote:
> I just merged support for local output sorting yesterday :-)
> This allows to sort the data before it is given to the OutputFormat.
>
> It is done like this:
> myData.write(myOF).sortLocalOutput(1, Order.ASCENDING);
>
> See the programming guide for details (only in master, not online).
>
> Full sorting can be done with a DOP=1 data sink.
> Full parallel sorting is not supported yet (requires range partitioning and
> data stats for good partitioning bins).
>
> Best, Fabian
>
> 2015-02-04 14:38 GMT+01:00 Timo Walther <tw...@apache.org>:
>
> > Hey,
> >
> > is it correct that we currently do not support sorting without any
> > grouping? I had this question by 2 users in the last weeks and now I also
> > need this functionality.
> >
> >
> > Is it possible to sort e.g. a word count result Tuple2<String, Integer>
> by
> > count?
> >
> >
> > Regards,
> > Timo
> >
>
Re: Sorting of fields
Posted by Fabian Hueske <fh...@gmail.com>.
I just merged support for local output sorting yesterday :-)
This allows to sort the data before it is given to the OutputFormat.
It is done like this:
myData.write(myOF).sortLocalOutput(1, Order.ASCENDING);
See the programming guide for details (only in master, not online).
Full sorting can be done with a DOP=1 data sink.
Full parallel sorting is not supported yet (requires range partitioning and
data stats for good partitioning bins).
Best, Fabian
2015-02-04 14:38 GMT+01:00 Timo Walther <tw...@apache.org>:
> Hey,
>
> is it correct that we currently do not support sorting without any
> grouping? I had this question by 2 users in the last weeks and now I also
> need this functionality.
>
>
> Is it possible to sort e.g. a word count result Tuple2<String, Integer> by
> count?
>
>
> Regards,
> Timo
>
Re: Sorting of fields
Posted by Timo Walther <tw...@apache.org>.
Ok, I found an earlier discussion about it. Sorry for the mail.
However, I think this is a very important feature and I should be added
soon.
On 04.02.2015 14:38, Timo Walther wrote:
> Hey,
>
> is it correct that we currently do not support sorting without any
> grouping? I had this question by 2 users in the last weeks and now I
> also need this functionality.
>
>
> Is it possible to sort e.g. a word count result Tuple2<String,
> Integer> by count?
>
>
> Regards,
> Timo
>