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From Fabian Hueske <fhue...@gmail.com>
Subject Re: Changed the behavior of "DataSet.print()"
Date Thu, 28 May 2015 12:13:09 GMT
I would avoid to call it printXYZ, since print()'s behavior changed to
eager execution.

2015-05-28 14:10 GMT+02:00 Robert Metzger <rmetzger@apache.org>:

> Okay, you are right, local is actually confusing.
> I'm against introducing "worker" as a term in the API. Its still called
> "TaskManager". Maybe "printOnTaskManager()" ?
>
> On Thu, May 28, 2015 at 2:06 PM, Fabian Hueske <fhueske@gmail.com> wrote:
>
> > +1 for both.
> >
> > printLocal() might not be the best name, because "local" is not well
> > defined and could also be understood as the local machine of the user.
> > How about naming the method completely different (writeToWorkerStdOut()?)
> > to make sure users are not confused with eager and lazy execution?
> >
> >
> > 2015-05-28 13:44 GMT+02:00 Robert Metzger <rmetzger@apache.org>:
> >
> > > Hi Sebastian,
> > >
> > > thank you for the feedback. I agree that both variants have a right to
> > > exist.
> > >
> > > I would vote for adding another method to the DataSet called
> > "printLocal()"
> > > that has the old behavior.
> > >
> > > On Thu, May 28, 2015 at 1:01 PM, Kruse, Sebastian <
> > Sebastian.Kruse@hpi.de>
> > > wrote:
> > >
> > > > Hi everyone,
> > > >
> > > > I am a bit worried about that recent change of the print() method. I
> > can
> > > > understand the rationale that obtaining the stdout from all the
> > > > taskmanagers is cumbersome (although, for local debugging the old
> > print()
> > > > was fine).
> > > > However, a major problem, I see with the new print(), is, that now
> you
> > > can
> > > > only have one print() per plan, as the plan is directly executed as
> > soon
> > > as
> > > > print() is invoked. If you regard print() as a debugging means, this
> > is a
> > > > severe restriction.
> > > > I see use cases for both print() implementations, but I would at
> least
> > > > provide some kind of backwards compatibility, be at a parameter or a
> > > > legacyPrint() method or anything else. As I assume print() to be very
> > > > frequently used, a lot of existing programs would benefit from this
> and
> > > > might otherwise not be directly portable to newer Flink versions.
> What
> > do
> > > > you think?
> > > >
> > > > Cheers,
> > > > Sebastian
> > > >
> > > > -----Original Message-----
> > > > From: Robert Metzger [mailto:rmetzger@apache.org]
> > > > Sent: Dienstag, 26. Mai 2015 11:12
> > > > To: dev@flink.apache.org
> > > > Subject: Re: Changed the behavior of "DataSet.print()"
> > > >
> > > > I've filed a JIRA to update the documentation:
> > > > https://issues.apache.org/jira/browse/FLINK-2092
> > > >
> > > > On Fri, May 22, 2015 at 11:08 AM, Stephan Ewen <sewen@apache.org>
> > wrote:
> > > >
> > > > > Hi all!
> > > > >
> > > > > Me merged a patch yesterday that changed the API behavior of the
> > > > > "DataSet.print()" function.
> > > > >
> > > > > "print()" now prints to stdout on the client process, rather than
> the
> > > > > TaskManager process, as before. This is much nicer for debugging
> and
> > > > > exploring data sets.
> > > > >
> > > > > One implication of this is that print() is now an eager method (
> like
> > > > > collect() or count() ). That means that calling "print()"
> immediately
> > > > > triggers the execution, and no "env.execute()" is required any
> more.
> > > > >
> > > > > Greetings,
> > > > > Stephan
> > > > >
> > > > >
> > > >
> > >
> >
>

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