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https://issues.apache.org/jira/browse/MAPREDUCE-6823?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Steve Loughran updated MAPREDUCE-6823:
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Attachment: HADOOP-13786-HADOOP-13345-001.patch
This is the initial HADOOP-13786 001 PoC patch, to give the MR bit of the code
some testing too. It adds a new factory for FileOutputFormatter to use when
creating committers; the default one returns {{FileOutputCommitter}} instances
as normal; a special S3a one in {{hadoop-aws}} to handle S3a specific
operations.
Now, the other way to do this (given the need to keep the s3a code in the s3a
module) would be to allow a notion of a new algorithm, one which relayed to an
implementation of an interface. That would hand a problem not addressed here:
how to address subclasses of {{FileOutputFormat}} with custom subclasses of
{{FileOutputCommitter}}, and make it easier to add committers for other
non-FS-destinations, namely the other object stores.
However, it would be a more significant change to {{FileOutputCommitter}}; I
could go that way, but it'd need support before I started.
> FileOutputFormat to support configurable FileOutputCommitter factory
> --------------------------------------------------------------------
>
> Key: MAPREDUCE-6823
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-6823
> Project: Hadoop Map/Reduce
> Issue Type: Bug
> Components: mrv2
> Affects Versions: 3.0.0-alpha2
> Environment: Targeting S3 as the output of work
> Reporter: Steve Loughran
> Assignee: Steve Loughran
> Attachments: HADOOP-13786-HADOOP-13345-001.patch
>
>
> In HADOOP-13786 I'm adding a custom subclass for FileOutputFormat, one which
> can talk direct to the S3A Filesystem for more efficient operations, better
> failure modes, and, most critically, as part of HADOOP-13345, atomic commit
> of output. The normal committer relies on directory rename() being atomic for
> this; for S3 we don't have that luxury.
> To support a custom committer, we need to be able to tell FileOutputFormat
> (and implicitly, all subclasses which don't have their own custom committer),
> to use our new {{S3AOutputCommitter}}.
> I propose:
> # {{FileOutputFormat}} takes a factory to create committers.
> # The factory to take a URI and {{TaskAttemptContext}} and return a committer
> # the default implementation always returns a {{FileOutputCommitter}}
> # A configuration option allows a new factory to be named
> # An {{S3AOutputCommitterFactory}} to return a {{FileOutputCommitter}} or
> new {{S3AOutputCommitter}} depending upon the URI of the destination.
> Note that MRv1 already supports configurable committers; this is only the V2
> API
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