Have you tried to use a custom accumulator that just appends to a list?
2015-06-29 12:59 GMT+02:00 Andra Lungu <lungu.an...@gmail.com>:
> Hey Fabian,
>
> I am aware of the way open, preSuperstep(), postSuperstep() etc can help me
> within an interation, unfortunately I am writing my own method here. I
> could try to briefly describe it:
>
> public static final class PropagateNeighborValues implements
> NeighborsFunctionWithVertexValue(...) {
> @Override
> public void iterateNeighbors(Iterable..., Collector...) {
> while(iterator.hasNext) neighbors++;
> // and I would need something like
> appendToFile(myAwesomeFile, neighbors);
> }
> }
>
> Open() and synchronised are definitely not doing the trick for me right
> now.
> Any other way !? :(
>
> On Mon, Jun 29, 2015 at 11:36 AM, Fabian Hueske <fhue...@gmail.com> wrote:
>
> > You can measure the time of each iteration in the open() methods
> operators
> > within an iteration. open() will be called before each iteration.
> > The times can be collected by either printing to std out (you need to
> > collect the files then...) or by implementing a list accumulator. Each
> time
> > should include the iteration# und parallel task id.
> > After the execution, the acculuator will be available in the execution
> > result.
> >
> > Accumulators can of course also be used to collect number of messages,
> etc.
> >
> > Best, Fabian
> >
> > 2015-06-29 9:55 GMT+02:00 Flavio Pompermaier <pomperma...@okkam.it>:
> >
> > > Why don't you use Flink dataset output functions (like writeAsText,
> > > writeAsCsv, etc..)?
> > > Or if they are not sufficient you can implement/override your own
> > > InputFormat.
> > >
> > > From what is my experience static variables are evil in distributed
> > > environments..
> > > Moreover, one of the main strengths of Flink are its input/output APIs
> > so I
> > > would avoid to write to a file in that way.
> > >
> > > Of course, dataset.append() will be a very convenient API to add
> (IMHO).
> > >
> > > Best,
> > > Flavio
> > >
> > >
> > > On Sat, Jun 27, 2015 at 4:19 PM, Andra Lungu <lungu.an...@gmail.com>
> > > wrote:
> > >
> > > > Hey guys,
> > > >
> > > > Me again :) So now that my wonderful job finishes, I would like to
> > > monitor
> > > > it a bit (i.e. build some charts on the number of messages per
> vertex,
> > > > compute the total amount of time elapsed per computation per vertex,
> > > etc).
> > > >
> > > > The main computational-intensive operation is a coGroup. There,
> within
> > > the
> > > > iteration I count the number of "messages" sent and then I do simple:
> > > >
> > > > Files.append(messages, messagesTempFile, Charsets.UTF_8);
> > > >
> > > > The problem is that with this approach, I get a deadlock (yes!! Now
> > that
> > > I
> > > > know the code itself works I am positive that the deadlock comes from
> > the
> > > > append -this regarding my previous mail-). It is normal if you come
> to
> > > > think of it 200 something threads are trying to write to the same
> > file...
> > > >
> > > > A possible workaround is this one:
> > > >
> > > > public class Singleton {
> > > > private static final Singleton inst= new Singleton();
> > > >
> > > > private Singleton() {
> > > > super();
> > > > }
> > > >
> > > > public synchronized void writeToFile(String str) {
> > > > // Do whatever
> > > > }
> > > >
> > > > public Singleton getInstance() {
> > > > return inst;
> > > > }
> > > > }
> > > >
> > > > Singleton.getInstance().writeToFile("Hello!!");
> > > >
> > > > However, I am not sure how well Flink plays with synchronised....
> > > >
> > > > Is there a smarter way to do it?
> > > >
> > > > Thanks!
> > > >
> > > > Andra
> > > >
> > >
> >
>
