# Nginx proxy overhead with / out keep alive requests

**URL:** <https://www.ruby-forum.com/t/nginx-proxy-overhead-with-out-keep-alive-requests/220542>\
**Category:** NGINX\
**Created:** [June 12, 2012, 10:31pm UTC](https://www.ruby-forum.com/t/nginx-proxy-overhead-with-out-keep-alive-requests/220542 "2012-06-12T22:31:10Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![aris](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/258eb7/32.png) [@aris](https://www.ruby-forum.com/u/aris)\
**Post date:** [June 12, 2012, 10:31pm UTC](https://www.ruby-forum.com/t/nginx-proxy-overhead-with-out-keep-alive-requests/220542/1 "2012-06-12T22:31:10Z")

</div>

I have a test setup to measure the nginx overhead when plugged in front  
of a Jboss tomcat server.  
In tomcat I have deployed a test.jsp and use ab to measure the  
performance with the following scenarios

With out keep alive ab option  
ab → (ab -n 5000 -c 5  
[http://jboss.tomcat.url/test.jsp](http://jboss.tomcat.url/test.jsp))  
ab → → (ab -n 5000 -c 5  
[http://nginx.proxy.url/test.jsp](http://nginx.proxy.url/test.jsp))

With keep alive ab option (-k)  
ab → (ab -n 5000 -c 5 -k  
[http://jboss.tomcat.url/test.jsp](http://jboss.tomcat.url/test.jsp))  
ab → → (ab -n 5000 -c 5 -k  
[http://nginx.proxy.url/test.jsp](http://nginx.proxy.url/test.jsp))

The performance numbers WITHOUT keep alive is almost same BUT WITH keep  
alive option the performance numbers are very different and nginx takes  
about 5 secs more than the page accessed directly via tomcat. Tomcat  
takes only 0.503430 on an average

Why should there be so much of deviation with Keep alive? Is there  
anything I am missing?

-------------Tomcat per result using ab keep alive (ab -n 5000 -c 5 -k  
[http://jboss.tomcat.url/test.jsp](http://jboss.tomcat.url/test.jsp))-----------------------

Server Software: Apache-Coyote/1.1  
Server Hostname: jboss.tomcat.host  
Server Port: 9080

Document Path: /test.jsp  
Document Length: 301 bytes

Concurrency Level: 5  
Time taken for tests: 0.503430 seconds  
Complete requests: 5000  
Failed requests: 0  
Write errors: 0  
Keep-Alive requests: 4952  
Total transferred: 2944760 bytes  
HTML transferred: 1505000 bytes  
Requests per second: 9931.87 [#/sec] (mean)  
Time per request: 0.503 [ms] (mean)  
Time per request: 0.101 [ms] (mean, across all concurrent  
requests)  
Transfer rate: 5710.82 [Kbytes/sec] received

-------------Nginx perf result using ab keep alive (ab -n 5000 -c 5 -k  
[http://nginx.proxy.url/test.jsp](http://nginx.proxy.url/test.jsp)) --------------------------

Server Software: nginx  
Server Hostname: nginx.proxy.url  
Server Port: 80

Document Path: /test.jsp  
Document Length: 301 bytes

Concurrency Level: 5  
Time taken for tests: 5.440499 seconds  
Complete requests: 5000  
Failed requests: 0  
Write errors: 0  
Keep-Alive requests: 4952  
Total transferred: 2654760 bytes  
HTML transferred: 1505000 bytes  
Requests per second: 919.03 [#/sec] (mean)  
Time per request: 5.440 [ms] (mean)  
Time per request: 1.088 [ms] (mean, across all concurrent  
requests)  
Transfer rate: 476.43 [Kbytes/sec] received

-------------Tomcat per result WITHOUT ab keep alive (ab -n 5000 -c 5  
[http://jboss.tomcat.url/test.jsp](http://jboss.tomcat.url/test.jsp))-----------------------

Server Software: Apache-Coyote/1.1  
Server Hostname: jboss.tomcat.host  
Server Port: 9080

Document Path: /test.jsp  
Document Length: 301 bytes

Concurrency Level: 5  
Time taken for tests: 4.658429 seconds  
Complete requests: 5000  
Failed requests: 0  
Write errors: 0  
Total transferred: 2920000 bytes  
HTML transferred: 1505000 bytes  
Requests per second: 1073.32 [#/sec] (mean)  
Time per request: 4.658 [ms] (mean)  
Time per request: 0.932 [ms] (mean, across all concurrent  
requests)  
Transfer rate: 612.01 [Kbytes/sec] received

-------------Nginx perf result WITHOUT ab keep alive (ab -n 5000 -c 5  
[http://nginx.proxy.url/test.jsp](http://nginx.proxy.url/test.jsp)) --------------------------

Server Software: nginx  
Server Hostname: nginx.proxy.url  
Server Port: 80

Document Path: /test.jsp  
Document Length: 301 bytes

Concurrency Level: 5  
Time taken for tests: 4.916966 seconds  
Complete requests: 5000  
Failed requests: 0  
Write errors: 0  
Total transferred: 2630000 bytes  
HTML transferred: 1505000 bytes  
Requests per second: 1016.89 [#/sec] (mean)  
Time per request: 4.917 [ms] (mean)  
Time per request: 0.983 [ms] (mean, across all concurrent  
requests)  
Transfer rate: 522.27 [Kbytes/sec] received

=========Configuration=================

Tomcat maxKeepAlive connector is set to 100

Nginx keepalive\_requests 100;  
worker\_processes 4;  
worker\_connections 4098;  
use epoll;  
multi\_accept on;

Posted at Nginx Forum:

> **[Nginx proxy overhead with / out keep alive requests](https://forum.nginx.org/read.php?2,227472,227472#msg-227472)**
>
> I have a test setup to measure the nginx overhead when plugged in front of a Jboss tomcat server. In tomcat I have deployed a test.jsp and use ab to measure the performance with the following scenarios With out keep alive ab option ab --\>...

---

<div class="post-metadata">

**Author:** ![paphillon](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/67e7ee/32.png) [@paphillon](https://www.ruby-forum.com/u/paphillon)\
**Post date:** [June 13, 2012, 12:14pm UTC](https://www.ruby-forum.com/t/nginx-proxy-overhead-with-out-keep-alive-requests/220542/2 "2012-06-13T12:14:21Z")

</div>

Hello!

On Tue, Jun 12, 2012 at 04:30:51PM -0400, paphillon wrote:

> Why should there be so much of deviation with Keep alive? Is there  
> anything I am missing?

Unless you’ve configured keepalive to upstreams (see  
[Module ngx\_http\_upstream\_module](http://nginx.org/r/keepalive)) nginx will not use keepalive  
connections to tomcat. And the expected result is: nginx is in  
par with tomcat used directly without keepalive.

Nnumbers extracted from your data for clarity:

tomcat + keepalive: 9931.87 r/s  
tomcat w/o keepalive: 1073.32 r/s  
nginx + keepalive: 919.03 r/s  
nginx w/o keepalvie: 1016.89 r/s

All nginx numbers are about tomcat’s one without keepalive, as  
expected (see above).

The limiting factor is clearly tomcat’s connection establishment  
cost, which drops performance from 10k r/s to 1k r/s. You may  
want to configure upstream keepalive to cope with it if it’s really  
matters in you case (i.e. if real requests are as fast as test one  
you’ve used; usually real request processing takes much more than  
connection establishment). See the link above for details.

Maxim D.

---

<div class="post-metadata">

**Author:** ![paphillon](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/67e7ee/32.png) [@paphillon](https://www.ruby-forum.com/u/paphillon)\
**Post date:** [June 13, 2012, 7:53pm UTC](https://www.ruby-forum.com/t/nginx-proxy-overhead-with-out-keep-alive-requests/220542/3 "2012-06-13T19:53:08Z")

</div>

Hi Maxim,

Thanks for the insight! I had a hunch on the keepalive setting from  
nginx to tomcat, but did not really find anything in the document about  
that. I will give it a try and let you know the results. I am not sure  
if I will be able to use this keepalive in production as it requires  
upstream config and differs from the way we have architect Nginx  
configuration.

I am using nginx as a dynamic proxy which routes the clients calls  
(primarily web service calls) to different servers depending on the key  
the client passes via cookie or http headers. The url’s are in a map in  
the below form

```
 map $http_void $header_based_url{
    default "no_http_header";
    key1 server_instance_1_url;
    key2 server_instance_2_url;
    ......
}

```

location /xxx {  
proxy\_pass $header\_based\_url;  
}  
And to make it more simple to add / maintain the server url’s, the URL’s  
are stored in a flat file

I am not sure how I can use the keepalive over here other than the  
upstream or how do I make this upstream config compatible.

Regards

Posted at Nginx Forum:

> **[Re: Nginx proxy overhead with / out keep alive requests](https://forum.nginx.org/read.php?2,227472,227503#msg-227503)**
>
> I have a test setup to measure the nginx overhead when plugged in front of a Jboss tomcat server. In tomcat I have deployed a test.jsp and use ab to measure the performance with the following scenarios With out keep alive ab option ab --\>...

---

<div class="post-metadata">

**Author:** ![paphillon](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/67e7ee/32.png) [@paphillon](https://www.ruby-forum.com/u/paphillon)\
**Post date:** [June 13, 2012, 10:50pm UTC](https://www.ruby-forum.com/t/nginx-proxy-overhead-with-out-keep-alive-requests/220542/4 "2012-06-13T22:50:44Z")

</div>

upstream with keepalive has the results almost comparable with tomcat,  
so yes keepalive between nginx and tomcat really does the trick. 🙂

Unfortunately we cannot use the upstream as explained in my previous  
post, unless upstream can offer something like below

```
map $http_void $header_based_url{

   default "no_http_header";
   #These Key => URL's are currently stored in a flat file
   key1 server_instance_1_url_host;
   key2 server_instance_2_url_host;
    ......
 }

upstream http_backend {

  server $header_based_url_host;

  keepalive 100;

}

location /xxx {
   proxy_pass http_backend;
}

```

Posted at Nginx Forum:

> **[Re: Nginx proxy overhead with / out keep alive requests](https://forum.nginx.org/read.php?2,227472,227506#msg-227506)**
>
> I have a test setup to measure the nginx overhead when plugged in front of a Jboss tomcat server. In tomcat I have deployed a test.jsp and use ab to measure the performance with the following scenarios With out keep alive ab option ab --\>...