JATOS Fail to transfer data

Comments

• elisa

  February 21

  Hi, if you are using your own server, you can change this in the JATOS config, see the docs here:

  https://www.jatos.org/JATOS_Configuration.html#result-data
• kri

  February 24

  You might also think about why you need more the 5 MB of data per experiment run. It is quite some data you have there and you might run into other problems while running your experiment with many participants (potentially at the same time).
• stahlc

  June 12

  Hi, I've repeatedly been hit by this problem as a user of mindprobe. It would be great if it could be made more visible to users.

  Right now, the user only gets "0 Byte" in the Data size field of the Component Result, despite the study finishing without problems. One is left to guess why there are no data. No other feedback is given: The data size limit is not apparent to users (i.e., it is not stated anywhere on the JATOS server frontend), and there is no error message or any indication that the limit has been hit.

  The first time (during Covid), it took quite a while to discover the reason that my data were suddenly no longer uploaded, without having made any changes to the data-uploading code.

  Perhaps the field header in the Component Results table could read "Data size (limit: 5 MB)" (or whatever is the actual limit on the given server). The (i) Info popup could state something like "Data uploads above the limit may fail and result in 0 Bytes being stored."

  It would probably be best if an additional error message could be issued on the main study page.

  Thank you for the great work on JATOS!

  Best, Christoph
• kri

  June 13

  Hi Christoph!

  I understand your frustration, but actually JATOS does report an error in this case. To the request that sends result data that are too large JATOS returns with an HTTP status code of 400 and with a response message of "Result data size exceeds allowed 5.0 MB. Consider using result files instead.". But I can imagine that many studies do not check for failed requests and do not show or log the error message.

  The expected behavior of the experiment's code is that it checks the request's response and deals with errors. This way the code has a chance to e.g. resend the result data in a smaller version or turn to sending result files (who do not have this size limitation).

  But anyway the reality is that many experiments do not care, so I am thinking about your proposals. I have to think about it more thoroughly but your first two seem feasible. The last one with an error message on the study page is technically difficult and the study page is in my humble opinion the wrong place; it should be a result page.

  Yours:

  1) The field header in the Component Results table could read "Data size (current limit: 5 MB)".

  2) If this error happens during a study run we could display some overlay, similar to an popup, that shows an error message to the participant. Then the participant has the task to report this error to the experimenter.

  And I want to add a third:

  3) Set a flag in the database entry for the component result that states that at least once a request reached the size limit. And then in the JATOS UI / result page / in this result's row show some kind of notification, maybe in a bold and red text even, that states the size limitation breach.

  What do you think?

  Best,

  Kristian
• stahlc

  August 19

  Dear Kristian,

  thank you for taking care of this!

  And sorry that I missed the error, this must be frustrating for you! I did not see the error message, probably because it was returned to (and handled by) the JS code that lab.js provided for uploading the data. I am not firm enough in JS/Ajax to properly handle that stuff myself.

  I think your suggestions would be a good way forward, thank you!

  Best, Christoph