[
https://issues.apache.org/jira/browse/HADOOP-16085?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16820236#comment-16820236
]
Sean Mackrory commented on HADOOP-16085:
----------------------------------------
Left some feedback in-line on the pull-request (and for HADOOP-16221 too). Some
more general thoughts:
* Have been discussing with [[email protected]] whether or not the FileStatus
-> S3AFileStatus and schema changes should be separated out from the
enforcement. I think the best argument for that is that it's a smaller change
to get older clients to notify newer clients of changes whereas only the newer
ones will enforce. The other factor mentioned is the desire for keeping S3Guard
relatively storage-agnostic, but I honestly just don't see how we can do that
and still have a robust solution. S3 is popular enough to warrant a custom
solution that really does fix all the holes. Personally, I think we should just
keep this change together.
* I don't suppose there's an interface we can rely on to provide getETag() and
getVersionId(), is there? This is where Go's duck-typing would be nice so we
could eliminate 2 (or more) or the args to every constructor call. Not a big
deal. I have a small to do list of other little things to look into but as
you'll see on the PR, the overwhelming majority of my feedback is pretty
mechanical. I think overall this is looking like a good solid patch.
> S3Guard: use object version or etags to protect against inconsistent read
> after replace/overwrite
> -------------------------------------------------------------------------------------------------
>
> Key: HADOOP-16085
> URL: https://issues.apache.org/jira/browse/HADOOP-16085
> Project: Hadoop Common
> Issue Type: Sub-task
> Components: fs/s3
> Affects Versions: 3.2.0
> Reporter: Ben Roling
> Assignee: Ben Roling
> Priority: Major
> Attachments: HADOOP-16085-003.patch, HADOOP-16085_002.patch,
> HADOOP-16085_3.2.0_001.patch
>
>
> Currently S3Guard doesn't track S3 object versions. If a file is written in
> S3A with S3Guard and then subsequently overwritten, there is no protection
> against the next reader seeing the old version of the file instead of the new
> one.
> It seems like the S3Guard metadata could track the S3 object version. When a
> file is created or updated, the object version could be written to the
> S3Guard metadata. When a file is read, the read out of S3 could be performed
> by object version, ensuring the correct version is retrieved.
> I don't have a lot of direct experience with this yet, but this is my
> impression from looking through the code. My organization is looking to
> shift some datasets stored in HDFS over to S3 and is concerned about this
> potential issue as there are some cases in our codebase that would do an
> overwrite.
> I imagine this idea may have been considered before but I couldn't quite
> track down any JIRAs discussing it. If there is one, feel free to close this
> with a reference to it.
> Am I understanding things correctly? Is this idea feasible? Any feedback
> that could be provided would be appreciated. We may consider crafting a
> patch.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
