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Alejandro Abdelnur commented on MAPREDUCE-5108: ----------------------------------------------- Steve, AFAIK Pig uses the mapreduce API, the work done for binary compatibility only covers the mapred API. > Review support for Binary Compatibility for MR applications via YARN > -------------------------------------------------------------------- > > Key: MAPREDUCE-5108 > URL: https://issues.apache.org/jira/browse/MAPREDUCE-5108 > Project: Hadoop Map/Reduce > Issue Type: Improvement > Affects Versions: 2.0.3-alpha > Reporter: Arun C Murthy > Assignee: Zhijie Shen > Priority: Blocker > Fix For: 2.0.5-beta > > Attachments: Binary Backward Compatibility.pdf, > mr1_mr2_api_diff.tar.gz > > > As we get ready to ship out a beta/stable version of hadoop-2, it makes sense > to spend time reviewing support for existing MR applications (hadoop-1) to > migrate seamlessly. > We've done various pieces of work over time, let's track progress and > document things clearly. [~zjshen] has done a bunch of testing and results > look very promising so far. > The aim is to support applications using org.apache.hadoop.mapred.* api in a > binary compatible manner in hadoop-2 - thus, users can just take existing MR > applications jars, point them at YARN clusters and things just work. > Clearly, we might have some corner cases (haven't seen many so far), > including semantics (not just apis); however the intent is to, at least, > document them throughly if not actually fix them as feasible. > Also, it's clear that we will *not* be able to support > org.apache.hadoop.mapreduce api in a *binary compatible* manner due to the > interface changes we made in hadoop-0.21 (sigh), and hence, users using the > _new_ apis will have to re-compile (i.e. source compatible only). > Net, given that vast majority of users use the org.apache.hadoop.mapred api, > it's a very reasonable way to ease migration to hadoop-2. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators For more information on JIRA, see: http://www.atlassian.com/software/jira