Thanks Bill
So, uploading a large file will have no more impact on memory than
uploading a smaller file. Do I have that right?
Nick Didkovsky
Bill Barker wrote:
"Nick Didkovsky" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
Hello
After posting this question to the Commons mailing list, I have been
advised to "ask the tomcat folks."
I am using Commons FileUpload 1.1 to manage HTTP POST uploads with Tomcat
running as a JkMount'ed service of Apache
I am trying to analyze the strain on memory when many large files are
being uploaded from different clients simultaneously
I have two questions:
1) Before a POST'ed file upload reaches FileUpload, is all or part of it
already cached somewhere on the server's drive space or memory, or does
it arrive from the network directly to FileUpload for parsing? The latter
would be desirable, as each uploaded file would get written directly to
the temp directory as it arrives over the network, with no additional
overhead. I do see my temp file growing steadily as the upload proceeds.
Is this the only place on the server where resources are being allocated
for this file upload? Can someone verify/amend/ provide more details?
Assuming that you are using Httpd 2.x, and that I understand the Httpd API
enough :), then it will get read in ~8kb chunks and passed to Tomcat the
same way. This is all transparent to the InputStream that FileUpload sees.
Of course, Httpd has to read it from the network in order to pass it to
Tomcat, but for most cases doing 8kb in memory at a time shouldn't hurt
much.
2) I tried uploading a file whose size exceeds the max file size I set in
my test JSP page. The JSP handles the upload with FileUpload, and writes
a log file of activity with time-stamps. Checking the log, I see that my
page throws the SizeLimitExceededException almost immediately after the
client's POST reaches the server. Yet the client browser sits there and
waits for roughly the amount of time a full upload would take, and only
then does the browser display the SizeLimitExceededException. The wait is
longer for larger files. Can someone explain exactly what is happening
during this time interval between the exception being thrown on the
server and the exception appearing on the client? Is the file actually
being uploaded somewhere to the server after the
SizeLimitExceededException is thrown? If so, where is the upload going
and whose memory or disk resources are being utilized? Note that
FileUpload's temp directory does not show any temp file growing when this
exception is thrown. Yet there does seem to be some network activity
between the client and the server, but I am baffled as to what it could
be and what its implications might be.
Presumably, you are catching the Exception instead of just allowing it to be
thrown out of your JSP (or, wrapping it in a ServletException or otherwise
:). If your JSP handles this case by doing:
<% reponse.sendError(HttpServletResponse.SC_REQUEST_ENTITY_TOO_LARGE);
return; %>
then Httpd *should* just close the connection to the client, allowing for a
fast recycle.
Thank-you
Nick Didkovsky
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