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https://issues.apache.org/jira/browse/HADOOP-12444?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15135090#comment-15135090
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Steve Loughran commented on HADOOP-12444:
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Thanks for the patch on EOF
FWIW, you'd have caught this problem on running the S3a contract tests —and
been able to turn it off by editing the contract-test options.xml. Some other
filesystems (real posix ones) don't faill on a seek past the end, but only on
the read (they have to allow for a write). Anyway, what you have done at least
makes it consistent with HDFS.
However, I do have a strict policy regarding testing here, namely you have to
have run it yourself against at least one AWS instance. And I have to insistt
on that for everyone to avoid being seen as relaxing the criteria for some
patches
https://wiki.apache.org/hadoop/HowToContribute#Submitting_patches_against_object_stores_such_as_Amazon_S3.2C_OpenStack_Swift_and_Microsoft_Azure
Have you done it yet, and if so which one?
thanks
> Consider implementing lazy seek in S3AInputStream
> -------------------------------------------------
>
> Key: HADOOP-12444
> URL: https://issues.apache.org/jira/browse/HADOOP-12444
> Project: Hadoop Common
> Issue Type: Sub-task
> Components: fs/s3
> Affects Versions: 2.7.1
> Reporter: Rajesh Balamohan
> Assignee: Rajesh Balamohan
> Attachments: HADOOP-12444.1.patch, HADOOP-12444.2.patch,
> HADOOP-12444.WIP.patch
>
>
> - Currently, "read(long position, byte[] buffer, int offset, int length)" is
> not implemented in S3AInputStream (unlike DFSInputStream). So,
> "readFully(long position, byte[] buffer, int offset, int length)" in
> S3AInputStream goes through the default implementation of seek(), read(),
> seek() in FSInputStream.
> - However, seek() in S3AInputStream involves re-opening of connection to S3
> everytime
> (https://github.com/apache/hadoop/blob/trunk/hadoop-tools/hadoop-aws/src/main/java/org/apache/hadoop/fs/s3a/S3AInputStream.java#L115).
>
> - It would be good to consider having a lazy seek implementation to reduce
> connection overheads to S3. (e.g Presto implements lazy seek.
> https://github.com/facebook/presto/blob/master/presto-hive/src/main/java/com/facebook/presto/hive/PrestoS3FileSystem.java#L623)
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