# Keep-alive connection cause download hangs in Nginx after 0.7.67 **URL:** \ **Category:** NGINX\ **Created:** [January 27, 2011, 4:50pm UTC](https://www.ruby-forum.com/t/keep-alive-connection-cause-download-hangs-in-nginx-after-0-7-67/202362 "2011-01-27T16:50:26Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![dubstep](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/cdc98d/32.png) [@dubstep](https://www.ruby-forum.com/u/dubstep)\ **Post date:** [January 27, 2011, 4:50pm UTC](https://www.ruby-forum.com/t/keep-alive-connection-cause-download-hangs-in-nginx-after-0-7-67/202362/1 "2011-01-27T16:50:26Z")
Hello, I am running into this download hanging issue. We are using nginx as a download server with SSL and secure download module enabled. When using nginx-0.7.67, it works well. But when we try to upgrade to nginx-0.8.54, there is a download hanging issue. We figured out it is related to keep-alive header or reusing TCP connection. When we download a small file and it finished, then in a few seconds, in same browser, if trying to download again, the download hangs. Nginx doesn’t print out any log message. If we turn off keep-alive in either browser or nginx server in 0.8.54 by setting keepalive\_timeout 0;, then it works well. Our environment is: Solaris 10, nginx 0.7.67/0.8.54, secure download module, SSL. The other difference between 0.7.67 and 0.8.54 is in the error.log message. In 0.7.67, when download finished, it always print out message as below: 2011/01/27 15:27:31 [info] 12616#0: \*1 client xxx.xxx.xxx.xxx closed keepalive connection But in 0.8.54, it never prints out this message. We have same config file for both 0.7.67 and 0.8.54. I think setting keepalive\_timeout to 0 is just a workaround and it may have performance impact. Trying to find out if there is better solution for this. Thanks for any suggestions. Posted at Nginx Forum: > **[keep-alive connection cause download hangs in Nginx after 0.7.67](https://forum.nginx.org/read.php?2,170139,170139#msg-170139)** > > Hello, I am running into this download hanging issue. We are using nginx as a download server with SSL and secure download module enabled. When using nginx-0.7.67, it works well. But when we try to upgrade to nginx-0.8.54, there is a download hanging... ---
**Author:** ![WilliamOMS](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/w/839c29/32.png) [@WilliamOMS](https://www.ruby-forum.com/u/WilliamOMS)\ **Post date:** [January 27, 2011, 6:29pm UTC](https://www.ruby-forum.com/t/keep-alive-connection-cause-download-hangs-in-nginx-after-0-7-67/202362/2 "2011-01-27T18:29:15Z")
Hello! On Thu, Jan 27, 2011 at 10:48:40AM -0500, WilliamOMS wrote: > Our environment is: Solaris 10, nginx 0.7.67/0.8.54, secure download > I think setting keepalive\_timeout to 0 is just a workaround and it may > have performance impact. Trying to find out if there is better solution > for this. > > Thanks for any suggestions. Are you able to reproduce the problem without 3rd party modules? If yes - please provide more information (nginx -V output, config, debug log), see [GitHub - nginxinc/nginx-wiki: ARCHIVED -- Source for the now archived NGINX Wiki section of https://www.nginx.com · GitHub](http://wiki.nginx.org/Debugging) for details. Maxim D. ---
**Author:** ![WilliamOMS](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/w/839c29/32.png) [@WilliamOMS](https://www.ruby-forum.com/u/WilliamOMS)\ **Post date:** [January 27, 2011, 8:26pm UTC](https://www.ruby-forum.com/t/keep-alive-connection-cause-download-hangs-in-nginx-after-0-7-67/202362/3 "2011-01-27T20:26:44Z")
Hi Maxim, I can not reproduce this problem without secure download module. I will send email to author for help. Thanks Posted at Nginx Forum: > **[Re: keep-alive connection cause download hangs in Nginx after 0.7.67](https://forum.nginx.org/read.php?2,170139,170219#msg-170219)** > > Hello, I am running into this download hanging issue. We are using nginx as a download server with SSL and secure download module enabled. When using nginx-0.7.67, it works well. But when we try to upgrade to nginx-0.8.54, there is a download hanging... ---
**Author:** ![WilliamOMS](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/w/839c29/32.png) [@WilliamOMS](https://www.ruby-forum.com/u/WilliamOMS)\ **Post date:** [June 24, 2011, 4:40pm UTC](https://www.ruby-forum.com/t/keep-alive-connection-cause-download-hangs-in-nginx-after-0-7-67/202362/4 "2011-06-24T16:40:35Z")
Greetings, I had the exact same issues you are describing. I use nginx to reverse proxy to an application server backend running Windows+Apache+PHP. If keepalive\_timeout was non-zero, PDF downloads would hang on our website. If we set it to zero, everything worked perfectly. However, we run all our sites on SSL exclusively; The overhead of doing SSL Negotiation for every single HTTP request was hurting performance significantly. I noticed that the length of “hang” of the download was directly proportional to the value of keepalive\_timeout. If the keepalive was set to 60, it would take 60 seconds before the download appeared to “finish”. If it was 75, it appeared to the client that the download took 75 seconds. When inspecting the headers for the PDF response, I realized the issue. “Content-Encoding: gzip”. Why is this an issue? Because when the “Content-Length” header is computed on the backend in PHP, it is computing the length BEFORE it was gzipped. So, there is a difference between the “Content-Length” and the size of what is actually sent to the client. The actual amount of data sent to the client was gzipped, and SMALLER than the “Content-Length” header. In my case, PHP had zlib.output\_compression set to “On”, which compressed and altered the size of the PDF, making it smaller. Therefore, the client was waiting for data that wasn’t there. The client received all the data, but didn’t know it. It was waiting for the additional bytes. When the connection timed out (keepalive\_timeout), it finally “finished” successfully (although the client already had 100% of the data). When keepalive\_timeout was 0, nginx would close the connection immediately because nginx knew the request was complete- regardless of what Content-Length says- thus signalling the client to stop waiting for additional data. I would suggest making sure the data sent to the client is actually equal to what the “Content-Length” header says. Your application code could be inadvertently compressing it (like PHP was doing for me) or your backend webserver could be doing it (like Apache). I turned zlib compression Off in php.ini on my application server, let nginx do gzip for HTML data (nothing is modifying the PDFs anymore), and it completely resolved the issue. My keepalive\_timeout is set to 60 and performance has improved dramatically since we eliminated countless SSL Negotiation steps. Hope this helps! Posted at Nginx Forum: > **[Re: keep-alive connection cause download hangs in Nginx after 0.7.67](https://forum.nginx.org/read.php?2,170139,209671#msg-209671)** > > Hello, I am running into this download hanging issue. We are using nginx as a download server with SSL and secure download module enabled. When using nginx-0.7.67, it works well. But when we try to upgrade to nginx-0.8.54, there is a download hanging... ---
**Author:** ![WilliamOMS](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/w/839c29/32.png) [@WilliamOMS](https://www.ruby-forum.com/u/WilliamOMS)\ **Post date:** [January 27, 2011, 8:41pm UTC](https://www.ruby-forum.com/t/keep-alive-connection-cause-download-hangs-in-nginx-after-0-7-67/202362/5 "2011-01-27T20:41:11Z")
Am 27.01.2011 um 20:25 schrieb WilliamOMS: > Hi Maxim, > > I can not reproduce this problem without secure download module. I > will > send email to author for help. We have a similar problem in a configuration not involving NGINX at all (it’s a complex configuration with Load-Balancers, commercial firewalls and a “WAF” appliances…) I would be _highly_ interested in explanations of this phenomenon. So, if you get any leads, would you mind sharing? Thanks in advance.