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https://issues.apache.org/jira/browse/NIFI-1484?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15135970#comment-15135970
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Mark Payne commented on NIFI-1484:
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Joe,
An important concern that you have to consider here though is that 'right now'
- 1 millisecond is very ambiguous. 'Right now' on the local system may not be
the same time stamp as 'Right Now' on the system that the file system lives on.
For example, if 'now' on the local system is 5000 and you do a listing of
everything with a time stamp < 5000 using ListSFTP, then what if another file
comes in using a times ramp of 4950 (because that's 'now' on the remote
system)? You'd miss it. Even with ListFile, this may be possible since the file
system may be network mounted.
> ListFile holds unbounded list of files with matching time stamps
> ----------------------------------------------------------------
>
> Key: NIFI-1484
> URL: https://issues.apache.org/jira/browse/NIFI-1484
> Project: Apache NiFi
> Issue Type: Bug
> Components: Core UI, Extensions
> Affects Versions: 0.4.0, 0.5.0
> Reporter: Joseph Witt
>
> ListFile appears to hold an unbounded set of filenames that match the last
> timestamp. While this is understandable to handle the edge case of new data
> arriving at the same time it presents two problems. First we hold all of
> this information in state management which could put considerable pressure on
> both the local and remote stores but we also have it in memory before we
> persist it.
> Also, the entire state listing appears to show up in the UI without
> pagination or any limit on number of entries. This seems like a problem for
> the client-side as well. The server side should probably restrict this.
> Finally, it seems like the need for saving filenames seen at a given
> timestamp is only necessary if we're assuming the listing we do is 'as-of'
> RIGHT NOW. What is instead we did the listing based on a last modified time
> of 'RIGHTNOW'-1 millisecond or something like that? Then we should not have
> to worry at all about keeping a listing of names for the timestamp.
> The reason I think this is important is that it is not at all uncommon for a
> directory with large quantities of files to have data at the same time due to
> a copy operation not preserving original file attributes.
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