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RSE: ftp quit after each transfer [message #24068] Wed, 25 June 2008 09:08 Go to next message
Eclipse User
Originally posted by: tatsudoshi.criion.net

Hello,

I would like to ask if the ftp cmd QUIT means the client closes the
connection after each single transfer?

If that is the case, why is this so? I mean isn't there a risk of
getting the client a timeout for to many connection open and close cmds?

Also I would imagine this being a bit slower that keeping the connection
open and using a queue like a regular ftp client.
Re: RSE: ftp quit after each transfer [message #24385 is a reply to message #24068] Tue, 01 July 2008 16:59 Go to previous messageGo to next message
Martin Oberhuber is currently offline Martin Oberhuber
Messages: 983
Registered: July 2009
Senior Member
Hello tatsudoshi,

The problem with having a single FTP connection (plus queue of
downloads) is, that while a download is going on, that connection is
unusable for commands like LIST() or getFile() -- which would
essentially lead to the whole Eclipse IDE becoming unresponsive.

Therefore, we always create a new, additional FTP connection for each
download - and close it down immediately when the download completes.

Note, that the "main" connection which we use for LIST() and getFile()
is always kept open, so RSE remains responsive; only for downloads and
uploads we fork new connections.

I agree, that we could reach some performance improvement by "pooling"
the download connections as well, such that we have e.g. 1 "control"
connection for LIST and getFile() always open, plus 3 "pooled"
connections for downloads and uploads which we also keep open in a
pooled fashion. Most FTP clients work that way, but it needs additional
work to get it implemented.

For SSH connections, we already have a request open for such connection
pooling: https://bugs.eclipse.org/bugs/show_bug.cgi?id=230831#c24
If we manage to implement the connection pooling logic "generic", we
might be able to re-use it for FTP.

Help on that effort is very welcome, so if you're interested in helping
out with a patch, please let us know! We'll help you where we can.


Cheers,
--
Martin Oberhuber, Senior Member of Technical Staff, Wind River
Target Management Project Lead, DSDP PMC Member
http://www.eclipse.org/dsdp/tm

tatsudoshi wrote:
> Hello,
>
> I would like to ask if the ftp cmd QUIT means the client closes the
> connection after each single transfer?
>
> If that is the case, why is this so? I mean isn't there a risk of
> getting the client a timeout for to many connection open and close cmds?
>
> Also I would imagine this being a bit slower that keeping the connection
> open and using a queue like a regular ftp client.
Re: RSE: ftp quit after each transfer [message #24508 is a reply to message #24385] Tue, 01 July 2008 17:50 Go to previous message
Eclipse User
Originally posted by: tatsudoshi.criion.net

Thanks for the answer. I can see the problem. I would very much like to
help but I have no experience with ftp or net code at all so I may not
of much help in the first place. Also I have not made Java code since I
graduated so it would take some time for me to get productive. But if
you think I can do any good please let me know.
Re: RSE: ftp quit after each transfer [message #575618 is a reply to message #24068] Tue, 01 July 2008 16:59 Go to previous message
Martin Oberhuber is currently offline Martin Oberhuber
Messages: 983
Registered: July 2009
Senior Member
Hello tatsudoshi,

The problem with having a single FTP connection (plus queue of
downloads) is, that while a download is going on, that connection is
unusable for commands like LIST() or getFile() -- which would
essentially lead to the whole Eclipse IDE becoming unresponsive.

Therefore, we always create a new, additional FTP connection for each
download - and close it down immediately when the download completes.

Note, that the "main" connection which we use for LIST() and getFile()
is always kept open, so RSE remains responsive; only for downloads and
uploads we fork new connections.

I agree, that we could reach some performance improvement by "pooling"
the download connections as well, such that we have e.g. 1 "control"
connection for LIST and getFile() always open, plus 3 "pooled"
connections for downloads and uploads which we also keep open in a
pooled fashion. Most FTP clients work that way, but it needs additional
work to get it implemented.

For SSH connections, we already have a request open for such connection
pooling: https://bugs.eclipse.org/bugs/show_bug.cgi?id=230831#c24
If we manage to implement the connection pooling logic "generic", we
might be able to re-use it for FTP.

Help on that effort is very welcome, so if you're interested in helping
out with a patch, please let us know! We'll help you where we can.


Cheers,
--
Martin Oberhuber, Senior Member of Technical Staff, Wind River
Target Management Project Lead, DSDP PMC Member
http://www.eclipse.org/dsdp/tm

tatsudoshi wrote:
> Hello,
>
> I would like to ask if the ftp cmd QUIT means the client closes the
> connection after each single transfer?
>
> If that is the case, why is this so? I mean isn't there a risk of
> getting the client a timeout for to many connection open and close cmds?
>
> Also I would imagine this being a bit slower that keeping the connection
> open and using a queue like a regular ftp client.
Re: RSE: ftp quit after each transfer [message #575720 is a reply to message #24385] Tue, 01 July 2008 17:50 Go to previous message
Eclipse User
Originally posted by: tatsudoshi.criion.net

Thanks for the answer. I can see the problem. I would very much like to
help but I have no experience with ftp or net code at all so I may not
of much help in the first place. Also I have not made Java code since I
graduated so it would take some time for me to get productive. But if
you think I can do any good please let me know.
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