Heroku Load Pages Extremely Slow

[Jindi Huang]

Greetings,

I am sorry for having another problem here. I ran a fairly small scale experiment (80 participants at the same time) with few background calculations on Heroku but the pages were loading extremely slow. I used Standard 2X web dynos, Standard 2 Postgres and Hobby Redis, which seems to be enough for this purpose. 

The metric seems to show that both the response time and dyno load are very high (figures below shows the detailed statistics). Also, the logfile shows that there is something wrong with the postgres. I am not sure whether this is due to the limitation of the dyno or postgres I am using now or there are bugs in my code. 

Could you please provide some advice on which kind of bug in the code would cause this kind of problem? Thank you so much in advance for your help!!

Best wishes,

Jindi

[Chris @ oTree]

What version of oTree, according to the Server Check page?

What do you mean by background calculations? Do you mean you are doing calculations in the usual methods like before_next_page, after_all_players_arrive, etc? Or that you are running some special background process in another thread?

See the notes here about performance: https://otree.readthedocs.io/en/latest/server/heroku.html#server-performance

oTree Hub's Pro plan has a performance analysis tool that can give a lot of good info.

[Jindi Huang]

Hi Chris,

Thank you so much again for your prompt response! I am using oTree 3.3.6 (I did not update it to 5x since I am afraid there would be some other changes that cause problems). I just did some calculations using methods like "before_next_page". Do you think I should upgrade oTree to the latest version? 

Thank you for providing the notes! It's really helpful!

Best,

Jindi