According to my understanding, I think the Pregel is in same layer with MR, not a MR based language processor.
I think the 'Collective Communication' of BSP seems the core of the problem. For example, this BFS problem (http://blog.udanax.org/2009/02/breadth-first-search-mapreduce.html) can be solved at once w/o MR iterations. On Fri, Jun 26, 2009 at 3:17 PM, Owen O'Malley<omal...@apache.org> wrote: > > On Jun 25, 2009, at 9:42 PM, Mark Kerzner wrote: > >> my guess, as good as anybody's, is that Pregel is to large graphs is what >> Hadoop is to large datasets. > > I think it is much more likely a language that allows you to easily define > fixed point algorithms. I would imagine a distributed version of something > similar to Michal Young's GenSet. > http://portal.acm.org/citation.cfm?doid=586094.586108 > > I've been trying to figure out how to justify working on a project like that > for a couple of years, but haven't yet. (I have a background in program > static analysis, so I've implemented similar stuff.) > >> In other words, Pregel is the next natural step >> for massively scalable computations after Hadoop. > > I wonder if it uses map/reduce as a base or not. It would be easier to use > map/reduce, but a direct implementation would be more performant. In either > case, it is a new hammer. From what I see, it likely won't replace > map/reduce, pig, or hive; but rather support a different class of > applications much more directly than you can under map/reduce. > > -- Owen > > -- Best Regards, Edward J. Yoon @ NHN, corp. edwardy...@apache.org http://blog.udanax.org
