[ https://issues.apache.org/jira/browse/MAPREDUCE-4549?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13565633#comment-13565633 ]
Robert Joseph Evans commented on MAPREDUCE-4549: ------------------------------------------------ Do we want it on trunk? For example if I pass in -libjar a/foo.jar -libjar b/foo.jar in 1.0 everything will work and both foo.jar files will be on the classpath (I don't know why you would do this, but it is possible). Under YARN only one of them will even be shipped in the distributed cache, so there is no way at all for both of them to be on the classpath. With this patch it will output a warning message when a conflict occurs so people can try and fix the issue, but eventually we want to have the upper parts of the stack fix it, or we need to do what I was looking at doing initially and try to keep the colliding files separate by adding in support of sub directories in the distributed cache and using UUIDs. > Distributed cache conflicts breaks backwards compatability > ---------------------------------------------------------- > > Key: MAPREDUCE-4549 > URL: https://issues.apache.org/jira/browse/MAPREDUCE-4549 > Project: Hadoop Map/Reduce > Issue Type: Bug > Components: mrv2 > Affects Versions: 0.23.3, 2.0.2-alpha > Reporter: Robert Joseph Evans > Assignee: Robert Joseph Evans > Priority: Critical > Fix For: 2.0.3-alpha, 0.23.5 > > Attachments: MAPREDUCE-4549-trunk.patch, MR-4549-branch-0.23.txt > > > I recently put in MAPREDUCE-4503 which went a bit too far, and broke > backwards compatibility with 1.0 in distribtued cache entries. instead of > changing the behavior of the distributed cache to more closely match 1.0 > behavior I want to just change the exception to a warning message informing > the users that it will become an error in 2.0 -- 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