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Performance Tests

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2 years 9 months ago #106845 by Erwinx2
Hello,

I want to make some performance tests with LimeSurvey.
I am able to procceed a survey automatically, but the values of the inputs of a survey page doesnt show up in the db or the survey statistic page in the admin. There is only an IP recoreded

Is there any funny JavaScript stuff I should aware of while programatically triggering post requests?

Thank you in avance. :cheer:

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2 years 9 months ago - 2 years 9 months ago #106954 by Erwinx2
Update: Are there any hidden INPUT-TAGS generated by JavaScript at runtime which are nessesary to get the form-values into the DB? Which additional values are expected by the PHP-Classes exceopt the cookie and the token? Are there any exceptions related to start time or other values?
Last Edit: 2 years 9 months ago by Erwinx2.

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2 years 9 months ago #107027 by TMSWhite
If you are doing load testing using a scripting tool like WebLoad, you will need to disable one of the features within LimeSurvey that is designed to prevent resubmission of pages. Search for LEMpostKey in SurveyRuntimeHelper.php.

You can probably make your life easy by just changing this line:
$_SESSION[$LEMsessid]['LEMpostKey'] = mt_rand();

to
$_SESSION[$LEMsessid]['LEMpostKey'] = 999;

and then ensure that you have a LEMpostKey parameter with the same value in your load testing scripts.


Additionally, the best place to look for performance improvement is by reducing the memory footprint. See feature request #8928 . The serialization is in /application/helpers/expression/em_manager_helper.php

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2 years 8 months ago #107872 by Erwinx2
Thank you TMSWhite,

this works perfect.

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2 years 8 months ago #108880 by Erwinx2
Now after some testings on different platforms, I get a performance lack of several seconds in the last post request of a survey. What can I do to avoid this?

I read "em_manager_helper.php" but it seems this is a general architectural problem.

Is it because of collecting the answer-data until the last survey page? It seems a db-update issiues only on the last page of a survey, instead of every survey page.

thx.

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2 years 8 months ago #108934 by Mazi
1. Please test if you can reproduce the issue at the Limesurvey demo.

2. Please post a link to the activated survey so we can have a look.


Best regards/Beste Grüße,
Dr. Marcel Minke
(Limesurvey Head of Support)
Need Help? We offer professional Limesurvey support
Contact: marcel.minke(at)survey-consulting.com'"

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2 years 8 months ago - 2 years 8 months ago #108962 by Erwinx2
Hello,


I only can test your Demo if you provide the above mentioned hints "$_SESSION[$LEMsessid] = 999;" in your Demo-Version(s).

On our prefered Hosting Platform the effect only occurs, if there are more then one users at the same time involved. Otherwise it is not recognizable.

Some results:

30 users in 30 seconds = ~ 10 seconds latency on the last survey page

15 users in 15 seconds = ~ 7 seconds latency on the last survey page

1 user = 800 ms on the last survey page


I will ask my boss to provide a link to our survey, but to reproduce the effect it needs additional simulated users (see above).

Any additional suggestions?

Thx in advance
Last Edit: 2 years 8 months ago by Erwinx2.

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2 years 8 months ago - 2 years 8 months ago #108963 by Mazi
Sorry, we can't hack the demo :-)

What resources (CPU, memory, ...) are available at the server? Which DB do you use?


Best regards/Beste Grüße,
Dr. Marcel Minke
(Limesurvey Head of Support)
Need Help? We offer professional Limesurvey support
Contact: marcel.minke(at)survey-consulting.com'"
Last Edit: 2 years 8 months ago by Mazi.

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2 years 8 months ago #108964 by c_schmitz
Do you have email notification activated for your survey?

Best regards

Carsten Schmitz
LimeSurvey project leader

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2 years 8 months ago - 2 years 8 months ago #108965 by Erwinx2
Hello,

we reproduced the effect on nearly every hardware-configuration at Amazon AWS (including the high end mashines). We also tested a Nginx-Environment vs. LAMP in conjunction with the biggest DB-Instances.

aws.amazon.com/de/ec2/instance-types/

...and using the default MySQL/MyISAM.

Since the effect is bigger on Amazon, I am just migrating to a "normal" Hosting Provider we have tested too:

- RAM 16 GB
- 500 GB SSD
- 8 vCores
- classical LAMP-System

E-Mail-Notivication ist enabled. I could test it disabled.
Last Edit: 2 years 8 months ago by Erwinx2.

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2 years 8 months ago #108967 by c_schmitz
Most likely the email notification takes too long caused by a slow SMTP connection to you mail server.

Best regards

Carsten Schmitz
LimeSurvey project leader

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2 years 8 months ago #108970 by Erwinx2
That's it. Thank you! :laugh:

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