Hello all,

I am very impressed of limesurveys features. But on my server I get a very poor performance testing with ab -n100 -c10. Especially compared to the results of a small php-testsite on the same system:

Limesurvey (Home-URL /)

Requests per second: 4.20 [#/sec] (mean)
Time per request: 2379.019 [ms] (mean)
Time per request: 237.902 [ms] (mean, across all concurrent requests)
Transfer rate: 41.07 [Kbytes/sec] received

PHP-Testsite with some MySQL-Queries:

Requests per second: 174.85 [#/sec] (mean)
Time per request: 57.191 [ms] (mean)
Time per request: 5.719 [ms] (mean, across all concurrent requests)
Transfer rate: 1828.60 [Kbytes/sec] received

I am using nginx, php-fpm, php-apc + limesurvey (latest trunk from github, master-branch). Do you have any ideas why limesurvey is so slow?

Thanks in advance!, Jonas.

What is the home URL? A survey? The Survey List Page?

Take a look at the session folder for php.

Limesurvey creates very big session files.
In tests I had 2MB per Session when hitting the first page.

jelo wrote:

On a specific survey or in survey admin part ?

Denis

I focused on activated surveys. If it would be the admin session I wouldn't mind.

The problem is that if many user hit the first page of a survey link posted somewhere you can easily run out of space on dedicated mounted session/tmp partitions.

I am not sure, if the design could be changed, that a session file can be created when the user is reaching the second page. The first page could be used optional to ask for allowing setting cookies etc. The whole compliance law stuff which differ from country to country and industry to industry.

The performance issues occurre in every part of the application:
- at the first page (overview of all surveys)
- at the admin-area
- at surveys

I guess the translation module slows limesurvey massively down:

ab -n500 -c100

Using English translation as default:
Requests per second: 31.89 [#/sec] (mean)

Using German translation as default:
Requests per second: 5.71 [#/sec] (mean)

Profiling the code with XDebug shows that the translation consumes most of the CPU-Time.

Is there any way to speed up the translation?

Thank you for your help, Jonas.

What is you aim of the whole test? For what kind of survey / purpose do you plan to use Limesurvey.

What hardware specs are used? How many GB RAM? Virtualization? Which stack?
You benchmark can be bad or fantastic. Perhaps you expect to much.
How many "Complete requests" vs. "Failed requests" are in your benchmark results?

A "ab -n500 -c100" test brings e.g a VPS XEN with 1-2GB RAM down to its knees in seconds.