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Steve Loughran commented on HADOOP-13169: ----------------------------------------- this is a good find. # Have you run the hadoop-amazon and hadoop-azure distcp tests with this? # Concurrency. You've marked {{statusList}} as a concurrent list, implying there's concurrent use. But in {{writeToFileListing}} the list is shuffled,used and then clear()-d in an unsynced block. Is there anything to stop elements being added to the list between that shuffle/use and the clear() operation? as that would lose entries in the distcp > Randomize file list in SimpleCopyListing > ---------------------------------------- > > Key: HADOOP-13169 > URL: https://issues.apache.org/jira/browse/HADOOP-13169 > Project: Hadoop Common > Issue Type: Improvement > Components: tools/distcp > Reporter: Rajesh Balamohan > Priority: Minor > Attachments: HADOOP-13169-branch-2-001.patch, > HADOOP-13169-branch-2-002.patch, HADOOP-13169-branch-2-003.patch > > > When copying files to S3, based on file listing some mappers can get into S3 > partition hotspots. This would be more visible, when data is copied from hive > warehouse with lots of partitions (e.g date partitions). In such cases, some > of the tasks would tend to be a lot more slower than others. It would be good > to randomize the file paths which are written out in SimpleCopyListing to > avoid this issue. -- This message was sent by Atlassian JIRA (v6.3.4#6332) --------------------------------------------------------------------- To unsubscribe, e-mail: common-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: common-issues-h...@hadoop.apache.org