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https://issues.apache.org/jira/browse/ARROW-9935?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17192481#comment-17192481
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Weston Pace commented on ARROW-9935:
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I tried that out and Arrow's own S3 implementation does not run into this
issue. This would only affect the s3fs implementation. Either way, this is
not a big problem for me since I have the workaround and I might switch to the
builtin implementation anyways if the performance is significantly different.
> [Python] New filesystem API unable to read empty S3 folders
> -----------------------------------------------------------
>
> Key: ARROW-9935
> URL: https://issues.apache.org/jira/browse/ARROW-9935
> Project: Apache Arrow
> Issue Type: Bug
> Components: Python
> Affects Versions: 1.0.0
> Reporter: Weston Pace
> Priority: Minor
> Attachments: arrow_9935.py
>
>
> When an empty "folder" is created in S3 using the online bucket explorer tool
> on the management console then it creates a special empty file with the same
> name as the folder.
> (Some more details here:
> [https://docs.aws.amazon.com/AmazonS3/latest/user-guide/using-folders.html)]
> If parquet files are later loaded into one of these directories (with or
> without partitioning subdirectories) then this dataset cannot be read by the
> new dataset API. The underlying s3fs `find` method returns a "file" object
> with size 0 that pyarrow then attempts to read. Since this file doesn't
> truly exist a FileNotFoundError is thrown.
> Would it be safe to simply ignore all files with size 0?
> As a workaround I can wrap s3fs' find method and strip out these objects with
> size 0 myself.
> I've attached a script showing the issue and a workaround. It uses a public
> bucket that I'll leave up for a few months.
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