Hi, Sorry for starting a new thread. I'm facing the same problem as Ian, see the quoted mail below. We used 0.15.0 on our lab cluster before. Recently we are considering upgrading to 0.20.x, and notice the significant changes in MapReduce APIs.
To be frankly, *I think the new set of API is a step backward*. First, most of our old MR codes break, a lot of warnings on deprecated classes like JobConf, but no obvious advantage is brought by the new API. Second, the new APIs favor abstract classes over interfaces, see the changes in Mapper, Reducer and OutputCollector. Lots of our unit test cases are designed based on mock classes that implements OutputCollector, new API just break them all without a better solution for testing (MRUnit is not ready now, and it is not convenient for complex test cases) . I tried to subclass Context, but it was definitely not a nice experience. Maybe this is just my case, want to hear from other users about the APIs. Sincerely, Xiance Si On Fri, Jun 5, 2009 at 11:21 PM, Ian Soboroff <[email protected]> wrote: > > I just started playing with 0.20.0. I see that the mapred package is > deprecated in favor of the mapreduce package. Is there any > migration documentation for the new API (i.e., something more touristy > than Javadoc)? All the website docs and Wiki examples are on the old API. > > Sorry if this is on the mailing list... I searched a bit but came up > dry... > > In the same vein, it would be nice if release notes could have some > narrative to go along with the random assortment of JIRA issue numbers. > Especially when major API migration is in the works. > > Ian >
