Ken - Riak contains its own implementation of a MapReduce API. This API is written in Erlang and C and shares no code with Hadoop. We have, on occasion, described our API as "Hadoop like" to help people understand the differences between our implementation and others. For example:
* CouchDB's MapReduce incrementally builds a BTree thru the execution of views. Riak doesn't cache or store MapReduce results. Each job executes "from scratch" and returns results to caller. It is up to the caller to cache or store these results if needed. * Hadoop MapReduce jobs use HDFS or HDFS-adapted resources. Riak MapReduce jobs use data stored in a Riak cluster. * Riak MapReduce jobs take advantage of their execution environment. Map functions exploit data locality. This means map functions are sent to the node hosting the required data rather than streaming the data to a central coordinating node. The most recent version of Riak also includes improvements which has significantly boosted the efficiency of mapping over entire buckets of data. * Riak supports writing MapReduce functions in two languages: Erlang and Javascript. Erlang is the absolute fastest, in terms of raw speed, but Javascript runs a close second and is easier for most people to use. Depending on what your jobs are doing and which language, Erlang or Javascript, there are a few tunable parameters we can tweak to improve performance. More information about what your job is doing, how your cluster is set up, and the kinds of performance you're seeing would help us debug the situation. --Kevin On Sep 7, 2010, at 10:52 PM, Ken Matsumoto wrote: > Hi all, > > Is there difference between "MapReduce in Hadoop" and "MapReduce in RIAK"? > I tested these performances and there were difference even in the same > machine, same data. > I'd like to know the difference like: > > - Version? Which is newer or branched? > - Does RIAK build in on source level or binary? > - Number of performance tuning parameters? > - What else? > > Regards, > > Ken. > > -- > Ken Matsumoto > VP / Research & Development > Nomura Research Institute America, Inc. > NRI Pacific > 1400 Fashion Island Blvd., Suite 1010 > San Mateo, CA 94404, U.S.A. > > PLEASE READ：This e-mail is confidential and intended for the named recipient > only. If you are not an intended recipient, please notify the sender and > delete this e-mail. > > > _______________________________________________ > riak-users mailing list > [email protected] > http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com _______________________________________________ riak-users mailing list [email protected] http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com
