oTree and Heroku server: Maximum number of participants

[Jan]

Dear Chris, dear all,

I need to get an understanding, how many participants my server can handle simultaneously.

I am using Heroku and during the study I will use the highest (most "powerful") settings which are possible through oTree-Hub. (i.e. Redis-plan = premium 1; Dyno size = Standard-2X).

 

My study takes 5 minutes on average; the participants do not interact with each other; there are 11 oTree pages (i.e. participants click next 11 times).

I am not sure which information is relevant, so let me if other info is required.

 

How many participants will the server definitely handle at the same time? I don’t want to risk server errors like time-outs.

 

Very rough estimates would already be helpful!

 

 

Thank you very much in advance and best
Jan

[Chris @ oTree]

Everything I can tell you about server performance is here: https://otree.readthedocs.io/en/latest/server/heroku.html#server-performance

In particular, oTree Hub’s performance analysis can be very helpful. 

Sent from my phone

On Oct 4, 2021, at 2:23 AM, Jan <janbie...@gmail.com> wrote:



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[Jan]

Thanks a lot Chris! And yes, I understand that this is a complex topic :).

Maybe other users have experinece?  Will my limit be more like 100 or 300 or 1000 participants?

[Linfeng Li]

Hi Jan,

I have no problem inviting 3000+ subjects to participate in one session. I used the _room folder to enumerate through all the subjects, and hosted a session where each subject has a unique link.

Note, in my case, there may be at most 30/40 people actively participating at one time.

I was hosting the app on Heroku with two dynos paid at the highest possible level, and two databases on the rather pricy side. The cost for a month is more than $100 dollars.

If there is a valid concern for the performance on oTree-Hub, then, @Jan, I suppose you can host your app on Heroku instead?

All the best,

-Linfeng