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https://issues.apache.org/jira/browse/SSHD-812?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16429849#comment-16429849
]
Goldstein Lyor commented on SSHD-812:
-------------------------------------
{quote}
I don't really see the benefit of having multiple threads reading the input
stream.
It's more the process methods which should be called in an executor.
{quote}
What if there are multiple threads, but only one of them reads a command from
the input stream, and while it processes the response, another can read the
next command and so on... ? We would effectively be calling {{process}}
asynchronously
{quote}
the subsystem would have to use multiple channels for a single handle
{quote}
What if reading/writing/accessing a file handle is synchronized ?
In other words:
{code:java|title=Skeleton thread run() loop}
synchronized (in) {
Buffer cmd = readCommand(in);
}
Buffer reply = process(cmd);
synchronized (out) {
writeReply(out, reply);
}
{code}
{code:java|title=read/write access}
Buffer doRead(String handle) {
Handle h;
synchronized (handlesMap) {
h = handlesMap.get(handle);
}
Buffer data;
synchronized (h) {
data = readFromHandle(h);
}
return data;
}
{code}
> support asynchronization mode for sftp subsystem
> ------------------------------------------------
>
> Key: SSHD-812
> URL: https://issues.apache.org/jira/browse/SSHD-812
> Project: MINA SSHD
> Issue Type: New Feature
> Affects Versions: 1.7.0
> Environment: java1.8, linux
> Reporter: Zhenliang Su
> Assignee: Goldstein Lyor
> Priority: Minor
> Labels: asynchronous, sftp
> Attachments: Main.java, doRead.png
>
>
> I used SSHD as a middleman between client and target sftp server.
> I found that, when filezilla client directly connect to the target sftp
> server, it transfers fast. When filezilla client connect to the middleman, it
> transfers slow.
> I analyzed the source code of
> org.apache.sshd.server.subsystem.sftp.SftpSubsystem#doRead, and I found it
> behaves like block mode, and client's other SSH_FXP_READ request blocked in
> the same thread.
>
> my middleman code:
> [^Main.java]
>
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