Experiment not running reliably and other issues

PennController for IBEX Forums Support Experiment not running reliably and other issues

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  • #8663

    Hi Jeremy,

    my currently running and data collecting experiment stops working from time to time and this is a huge problem.
    The experiment has lots of images in it and sometimes these images do not load, making it impossible for my participants to finish it. I know that this has happened at least twice because participants complained that they got halfway through the experiment and then it stopped working. I could reproduce this while I had a very good internet connection, so I don’t think this is the problem.
    Is there anything I can do to prevent this? Do you think it would help to host the experiment on my own server? I have never done this before, but at this point I’d be willing to try and move the experiment if possible.
    Here is the link: https://farm.pcibex.net/r/rjzBWf/ You can use “1234” as participant code on the first screen if necessary.
    There have been other issues as well: often, changes in my code won’t be saved. Sometimes it works well enough, but sometimes it takes several minutes in which I paste in the new code again and again before changes will be saved. I know about copying the project as a workaround, but that only works for a few minutes and then the new file gets corrupted as well. For me, this bug has only gotten worse over time.

    I also noticed that the results function and files can’t be trusted anymore. Sometimes I check how many participants I have and it will be fewer than the last time I checked. After logging in and out, the missing participants are usually back (or I repeat to log in and out until they are). I also had at least one incomplete results file where whole parts of trials were missing, which I only noticed because the file size was suspiciously small. Again, after logging in and out, I could download a complete result file.

    I know you can’t fix all of this immediately, but I still wanted to let you know this happens.


    • This topic was modified 1 year, 6 months ago by sabrina.

    Hi Sabrina,

    Re. the image problem, this is likely due to the high number of requests for files sent to the server within a short time period. It would most likely improve with a dedicated server (as the farm’s server is already close to saturation all the time) but the issue has happened with a dedicated server too. The solution most likely to prevent this issue is to consolidate the images into a zip file. See this post on how to use the zip file method with the S3 service of the AWS Free Tier offer

    Re. the save problem, a less radical workaround consists in re-creating the file, rather than copying the whole project. Reference

    Re. the results, there are two known issues. The first is, it takes time for results to be added to the database, so you will likely need to wait a few hours before you can see the latest submission. The other issue is, if you try to access the results several times without refreshing the page, the different requests can sometimes conflict and you end up with incomplete or redundant results file. So ideally, always refresh the page before accessing the results. Reference

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