[
https://issues.apache.org/jira/browse/HADOOP-10987?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14143334#comment-14143334
]
Kihwal Lee commented on HADOOP-10987:
-------------------------------------
I will take option #1. I am making the protected method public. The protected
version of {{listLocatedStatus()}} exists for {{FilterFileSystem}}
implementations like {{ChecksumFileSystem}}, which will needs a composite
filter for applying both user-defined filter and its internal filter after this
change. Then users directly calling {{listLocatedStatus(Path, PathFilter)}} and
hitting a symlink to {{ChecksumFileSystem}} will get the correct result. The
new {{listStatusIterator()}} method should be made similar in order to properly
support it in {{ChecksumFileSystem}}. This approach will also make it easier
to covert FsShell to use RemoteIterator-based listing.
> Provide an iterator-based listing API for FileSystem
> ----------------------------------------------------
>
> Key: HADOOP-10987
> URL: https://issues.apache.org/jira/browse/HADOOP-10987
> Project: Hadoop Common
> Issue Type: Improvement
> Reporter: Kihwal Lee
> Assignee: Kihwal Lee
> Attachments: HADOOP-10987.patch
>
>
> Iterator based listing methods already exist in {{FileContext}} for both
> simple listing and listing with locations. However, {{FileSystem}} lacks the
> former. From what I understand, it wasn't added to {{FileSystem}} because it
> was believed to be phased out soon. Since {{FileSystem}} is very well alive
> today and new features are getting added frequently, I propose adding an
> iterator based {{listStatus}} method. As for the name of the new method, we
> can use the same name used in {{FileContext}} : {{listStatusIterator()}}.
> It will be particularly useful when listing giant directories. Without this,
> the client has to build up a huge data structure and hold it in memory. We've
> seen client JVMs running out of memory because of this.
> Once this change is made, we can modify FsShell, etc. in followup jiras.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
