| Summary: | Support sendfile with NIO and SSL | ||
|---|---|---|---|
| Product: | Tomcat 6 | Reporter: | M McClain <mmcclain> |
| Component: | Catalina | Assignee: | Tomcat Developers Mailing List <dev> |
| Status: | RESOLVED FIXED | ||
| Severity: | enhancement | ||
| Priority: | P2 | ||
| Version: | 6.0.16 | ||
| Target Milestone: | default | ||
| Hardware: | PC | ||
| OS: | All | ||
| Attachments: | Patch for Tomcat 6.0.16 | ||
Hi Mr McClain, the benefit of sendfile is that you can transfer data from one channel to another without reading the data into the java heap. this is not possible with SSL, since you have to do the encryption in memory, so the effort is wasted, and doing it this way, you will be wasting poller CPU cycles on SSL encryption, potentially slowing down the system's reaction time to IO events. so the transferTo is supposed to read from the one buffer to another without reading data into memory (the java heap), this effort doesn't work with NIO ssl. what would have to be done here, is that we moved the send file to a separate thread, but it still wouldn't be a true send file. Filip I understand what you're saying about doing too much in the poller thread. I was trying to accomplish handling hundreds of clients that could simultaneously download a 200 MB file without tying up a separate thread per client on blocking I/O. And I hoped the NIO mechanism would additionally use less RAM. Unfortunately, from the servlet layer we only have access to an OutputStream. Changing this to an enhancement since there isn't anything broken here. Patches along the lines of Filip's suggestion welcome. Proposal for inclusion and performance improvement is added here http://svn.apache.org/viewvc?rev=720724&view=rev http://svn.apache.org/viewvc?rev=720728&view=rev The important thing is to never call a blocking method within the poller Proposal for inclusion in 6.0.x branch has been created. This has been fixed in 6.0.x and will be included in 6.0.19 onwards. |
Created attachment 22092 [details] Patch for Tomcat 6.0.16 We upgraded to Tomcat 6.0 to take advantage of NIO. We have a couple servlets which use SSL for secure download of very large files and needed it to scale. Disappointed that the sendfile functionality didn't work with NIO when using SSL, I dug in until I got something to work. I'm attaching a patch. The part that I'm least comfortable was the change to SecureNioChannel because I didn't know why the check was there to begin with.