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https://issues.apache.org/jira/browse/HADOOP-8490?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13291229#comment-13291229
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Daryn Sharp commented on HADOOP-8490:
-------------------------------------
The cache partitioning would be extremely useful when you _do want_ the fs
instance cached, but don't want it to collide with other cached instances. Ex.
you want to be able to close all the filesystems that have been acquired after
an operation. It's not a one-off thing in the NM. It would also be nice for
the FsShell to get a partition in the cache to avoid closing a caller's
filesystems.
One problem is when code does a {{FileSystem.get(...)}} in many places and
expects to get the same fs instance. Using {{newInstance}}, which I
originally thought of, does not address that case w/o modifying all the code
(which isn't always feasible) to pass around and use that fs instance. Code
that does {{Path#getFileSystem(...)}} won't necessarily know up front which
unique instances to obtain and then converting the code to pass around and use
the list of unique instances would be extremely painful. Basically the user is
forced to maintain their own cache of filesystems...
bq. Adding conf as a key to current FileSystem cache may break many existing
applications.
How so? The cache key is invisible/private?
> Add Configuration to FileSystem cache key
> -----------------------------------------
>
> Key: HADOOP-8490
> URL: https://issues.apache.org/jira/browse/HADOOP-8490
> Project: Hadoop Common
> Issue Type: Bug
> Components: fs
> Affects Versions: 0.23.0, 0.24.0, 2.0.0-alpha
> Reporter: Daryn Sharp
> Assignee: Daryn Sharp
>
> The {{FileSystem#get(URI, Configuration}} does not take the given
> {{Configuration}} into consideration before returning an existing fs instance
> from the cache with a possibly different conf.
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