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From "Steve Loughran (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HADOOP-13600) S3a rename() to copy files in a directory in parallel
Date Fri, 12 Jan 2018 23:26:02 GMT

    [ https://issues.apache.org/jira/browse/HADOOP-13600?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16324725#comment-16324725

Steve Loughran commented on HADOOP-13600:

Not looked at this for a while, I'll try and take a look in detail, especially now the committer
is merged in.

One thing I've realised is our copy operation isn't doing what we do elsewhere; shuffle the
list of files so there's more scattering of workload across shards in the bucket, so less
risk of throttling.

* from the list, grab the first batch to copy (say, same amount as we can delete in a single
* pick out the first few largest files to start copying first
* shuffle the rest of the batch

This is what I've done in [cloudup|https://github.com/steveloughran/cloudup/blob/master/src/main/java/org/apache/hadoop/tools/cloudup/Cloudup.java]
and I believe it makes for a fast upload

> S3a rename() to copy files in a directory in parallel
> -----------------------------------------------------
>                 Key: HADOOP-13600
>                 URL: https://issues.apache.org/jira/browse/HADOOP-13600
>             Project: Hadoop Common
>          Issue Type: Sub-task
>          Components: fs/s3
>    Affects Versions: 2.7.3
>            Reporter: Steve Loughran
>            Assignee: Sahil Takiar
>         Attachments: HADOOP-13600.001.patch
> Currently a directory rename does a one-by-one copy, making the request O(files * data).
If the copy operations were launched in parallel, the duration of the copy may be reducable
to the duration of the longest copy. For a directory with many files, this will be significant

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