Uploading file behaviour in Mongrel

rubyonrails-talk
1

Hi

Please could someone clarify how Mongrel behaves when uploading files? I have an application with Apache which proxies to about 5 mongrels. Files are uploaded to the system from mobile PDAs using GPRS, and the files are about 1 - 3 MB (so uploads take several minutes). Will this mean that a Mongrel will be tied up serving the upload for the duration of the upload? I know Rails is single threaded, but I thought Mongrel wasn't. I expect (perhaps wrongly) that Mongrel creates a new thread that handles the upload, streams it to a TempFile (or something like it), then when it is ready, passes the request on to Rails, which deals with it. That is what the trace from the server looks like, as the upload actions take a few milliseconds to complete. Or is it that for the duration of the upload, that Mongrel will be blocked and won't service requests until the upload is complete?

Thanks very much for anybody's help.

2

You are correct in your assumption that mongrel will write to a tempfile and invoke rails when the upload has completely finished.

Best regards

Peter De Berdt

3

Hi Peter

Thanks. Does that mean that a Mongrel will spawn a new thread to deal with the file upload and still be able to service other requests in the meantime?

Cheers

4

I was at Railscon Europe and the guy from Twitter said that Mongrel was single thread. Their config is set to only send one job at a time to each mongrel using some of the newer Apache load balancing stuff. So, tempfile or not, it may be a bit of a wait. He recommended passing off long-running jobs to a daemon not sure how you'd do this for file upload though.

5

I was at Railscon Europe and the guy from Twitter said that Mongrel was single thread. Their config is set to only send one job at a time to each mongrel using some of the newer Apache load balancing stuff. So, tempfile or not, it may be a bit of a wait. He recommended passing off long-running jobs to a daemon not sure how you'd do this for file upload though.

mongrel is single threaded from the point of view of serving rails requests, which was all that was discussed at that session. Other than that it is multithreaded (http://mongrel.rubyforge.org/faq.html) and uploading a file won't block a mongrel instance (you can even show an upload progress page - see http://mongrel.rubyforge.org/docs/upload_progress.html Fred