I'm thoroughly confused about which API is the recent one, which is the old one and which method I should be using to write MapReduce applications.
I'm under the impression that MRv2 is primarily driven by the org.apache.hadoop.mapreduce.* packages and MRv1 is primarily driven by the org.apache.hadoop.mapred.* packages. I've been led to believe that MRv2 applications extend MapReduceBase and implement Mapper, Reducer etc. and conversely the MRv1 applications extend Mapper, Reducer directly. However I can not find a canonical statement to back any of this up. What's more I keep finding conflicting statements about these, such as "'Hadoop - the definitive guide' gives example in MRv2 format" but then I look at the examples and they use org.apache.hadoop.mapreduce.* packages, but extend Mapper and extend Reducer, not MapReduceBase... Can someone either point me at a canonical resource or just confirm / deny my assumptions? Kind regards -- [image: cid:1CBF4038-3F0F-4FC2-A1FF-6DC81B8B6F94] First Option Software Ltd Signal House Jacklyns Lane Alresford SO24 9JJ Tel: +44 (0)1962 738232 Mob: +44 (0)7710 160458 Fax: +44 (0)1962 600112 Web: www.b <http://www.fosolutions.co.uk/>espokesoftware.com<http://bespokesoftware.com/> -- ____________________________________________________ This is confidential, non-binding and not company endorsed - see full terms at www.fosolutions.co.uk/emailpolicy.html First Option Software Ltd Registered No. 06340261 Signal House, Jacklyns Lane, Alresford, Hampshire, SO24 9JJ, U.K. ____________________________________________________