That sounds great to me, maybe just a mention in the wiki that the two functionalities are tied together will help the idea click for people. Either way this will be a big help I think.
On Thu, Feb 21, 2013 at 3:24 PM, Maja Kabiljo <majakabi...@fb.com> wrote: > Eli, that's an interesting idea, we could have some class which user > extends and which is there only for aggregator registration. Sometimes we > want to register some aggregators later on during the computation, so we > need to keep allowing registration from masterCompute too. > > But I think for users the biggest problem is to realize that they have > to extend and set MasterCompute/this new class in order to use aggregators. > Currently, if user tries to aggregate a value to unregistered aggregator he > will get an exception, but if he tries to get the value of unregistered > aggregator he will just get null. So maybe adding a warning message in that > case, together with a wiki page, might be enough? What do you think? > > From: Eli Reisman <apache.mail...@gmail.com> > Reply-To: "user@giraph.apache.org" <user@giraph.apache.org> > Date: Thursday, February 21, 2013 10:25 AM > > To: "user@giraph.apache.org" <user@giraph.apache.org> > Subject: Re: InputFormat for the example SimpleMasterComputeVertex > > Thanks for the explanation, that makes sense. I would love to see a wiki > page at some point, you have so much knowledge of this piece of Giraph from > all your dev work on it and have also the additional bonus of experience > running big cluster jobs using these features so you have a lot of insight > to share. > > Would there be any point to a future JIRA to break out the aggregator > registration from the master compute stuff, at least from the user's view? > Or is it not that confusing once you've used them a bit? > > > On Thu, Feb 14, 2013 at 4:52 PM, Maja Kabiljo <majakabi...@fb.com> wrote: > >> Progressable exception can be caused by many different reasons (it's >> totally unrelated to aggregators), and when looking at which exception it's >> caused by users should get better sense about what's going on. >> What you are suggesting about providing default master compute is not >> doable, since the part which needs to be done there is aggregator >> registration. We can't know what kind of aggregators (names and types) an >> application needs. >> I remember I was talking about writing a short tutorial for aggregators >> long time ago, sorry for not doing that, will try to get to it soon. >> >> From: Eli Reisman <apache.mail...@gmail.com> >> Reply-To: "user@giraph.apache.org" <user@giraph.apache.org> >> Date: Thursday, February 14, 2013 2:23 PM >> >> To: "user@giraph.apache.org" <user@giraph.apache.org> >> Subject: Re: InputFormat for the example SimpleMasterComputeVertex >> >> Other folks on the list are also having this problem with the >> progressable utile exception & job failures. I don't know much about master >> compute usage but if it is needed to make the aggregators work, maybe we >> should have a default dummy class that just handles aggregators if no other >> master compute is specified? Or a wiki page? The progressable error message >> does not lead us to this conclusion directly. >> >> On Wed, Feb 13, 2013 at 3:04 AM, Maria Stylianou <mars...@gmail.com>wrote: >> >>> Hey, >>> >>> I am trying to run the example SimpleMasterComputeVertex, but no >>> matter which Input Format and graph I give, it doesn't work. Each worker >>> gives the error: >>> >>> Caused by: java.lang.*NullPointerException* >>> at >>> org.apache.giraph.examples.*SimpleMasterComputeVertex.compute*(SimpleMasterComputeVertex.java:*42*) >>> >>> This line 42 is the first line of the compute() >>> public void compute(Iterable<DoubleWritable> messages){ >>> >>> So I guess, the initialization is not done correctly, because the >>> input file does not have the correct format. >>> >>> Any help would be appreciated, >>> Thanks! >>> Maria >>> -- >>> Maria Stylianou >>> Intern at Telefonica, Barcelona, Spain >>> Master Student of European Master in Distributed >>> Computing<http://www.kth.se/en/studies/programmes/master/em/emdc> >>> Universitat Politècnica de Catalunya - BarcelonaTech, Barcelona, Spain >>> KTH Royal Institute of Technology, Stockholm, Sweden >>> >>> >> >