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https://issues.apache.org/jira/browse/VFS-640?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16139746#comment-16139746
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L commented on VFS-640:
-----------------------
Well, if it is called recursively for layered filesystems, it is *different*
provider, I guess.
And as for the original case: it was an SFTP provider where the server had a
lot of files (like more than 2000) in the root directory for the user.
> Synchronized AbstractOriginatingFileProvider.getFileSystem is too broad
> -----------------------------------------------------------------------
>
> Key: VFS-640
> URL: https://issues.apache.org/jira/browse/VFS-640
> Project: Commons VFS
> Issue Type: Bug
> Affects Versions: 2.0, 2.1
> Reporter: L
> Attachments: ParallelConnTest.java, patch_VFS640.diff
>
>
> Currently (rev. 1802455) this method looks like this:
> {code:java}
> protected synchronized FileSystem getFileSystem(final FileName rootName,
> final FileSystemOptions fileSystemOptions)
> throws FileSystemException
> {
> FileSystem fs = findFileSystem(rootName, fileSystemOptions);
> if (fs == null)
> {
> // Need to create the file system, and cache it
> fs = doCreateFileSystem(rootName, fileSystemOptions);
> addFileSystem(rootName, fs);
> }
> return fs;
> }
> {code}
> Given that there is a single instance of a provider per scheme, a very slow
> server that is being accessed first time will block *all* other threads
> trying to access some other resources via the same provider.
> We have a server that takes sometimes 20-30 seconds in doCreateFileSystem. We
> do not mind the thread trying to access this method taking that long, but
> because of that "synchronized" we end up having multiple threads accessing
> unrelated servers for the same scheme blocked.
> PS. Actually, it is not only AbstractOriginatingFileProvider. The same
> "provider-scoped" lock is present in AbstractLayeredFileProvider,
> TemporaryFileProvider, and UrlFileProvider
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