MR2: Map tasks rewrite data once even if output fits in sort buffer -------------------------------------------------------------------
Key: MAPREDUCE-3252 URL: https://issues.apache.org/jira/browse/MAPREDUCE-3252 Project: Hadoop Map/Reduce Issue Type: Bug Components: mrv2, task Affects Versions: 0.23.0 Reporter: Todd Lipcon Assignee: Todd Lipcon Priority: Critical I found that, even if the output of a map task fits entirely in its sort buffer, it was rewriting the output entirely rather than just renaming the first spill into place. This is due to RawLocalFileSystem.rename() falling back to a copy if renameTo() fails. The first rename attempt was failing because no one has called mkdir for the output directory yet. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa For more information on JIRA, see: http://www.atlassian.com/software/jira