How do I use CFTHREAD in combination with CFFILE Upload

Question

I've been reading how CFTHREAD is supposed to release the
client so that long-lasting operations like a CFFILE upload can
continue to do their business while the client does something else.
How does this work exactly? I can't find any concrete
references. For example, I have a regular file upload form. A user
uploads a large file, say 100Mb, and I want to use CFTHREAD (or
something) to handle the upload process, which I know may take
hours depending on the connection, and immediately return the page
for the client saying "Your file is being processed. Please check
back later."
I tried wrapping some CFFILE code with CFTHREAD, but when I
ran it the page just sat there working while the file was being
uploaded, so I did not witness any change whatsoever in how its
being handled. What am I missing?
<cfthread action="run" name="uploadVideo">
<cffile
action="upload"
destination = "/var/www/video1/assetsIN"
nameconflict="overwrite"
filefield="video" />
</cfthread>
Thanks for any help.
UPDATE: I asked Ben Forta this in an email yesterday and here
was his response:
What you are doing is correct. The actual file processing
(getting the uploaded file) will not happen in a separate thread.
Were you expecting a separate thread for the upload itself? CF
can’t do that for you s CF does not have the file until it is
uploaded. Actually, CF is not even called until the form is
submitted (which includes the file being uploaded). It sounds like
you want the browser to do an upload in the background. This may be
doable using JavaScript and Ajax type controls. Or maybe using
browser tabs or something. -Ben

Answer 1

With file uploads the time consumption is between the client
PC and the web
server, not the web server and the CF server (which are
usually on the same
machine). All <cffile action="upload"> does is copy the
uploaded file from
the web server's temp upload dir to [wherever you tell it to
go]: it's a
local process, and should be fairly quick; certainly compared
to the
process of getting it to the web server in the first place.
Even if the data transmission was between the client PC and
the CF server,
you can't expect <cfthread> to somehow increase the
bandwitdh and speed up
the file upload between the two machines.
<cfthread> could come into its own if you had some file
processing to
perform on the file *after* it's uploaded: unzipping it,
doing some image
manipulation, parsing a CSV file into a DB, that sort of
thing. Not for
the initial upload.
Adam