Fill in the blanks activity memory leak, activity uses 2 GB of memory in moodle but works fine on wordpress

[mgancarzdsi]

Strange scenario here, but I think there is some slight implementation differences between the way the Fill in the blanks activity works on Moodle versus Wordpress that cause a memory leak on the client browser side.

This activity: https://h5p.org/node/456374 seems to work fine on h5p.org and our own Wordpress site. However, when we import the .h5p file it into our Moodle, clicking "Check" causes Google Chrome to start using memory until it reaches about 2 GB, at which point the tab crashes. In Internet Explorer it takes a while but works, though it uses up roughly 1.7 GB of memory while the activity grading is taking place.

Deleting one of the questions does reduce the memory usage and allows the "Check" to complete without Google Chrome crashing.

We created the activity in our Moodle, on Moodle version 3.5.3 and H5P plugin version 1.14. I also updated our H5P plugin to latest 1.17.1 and the same behaviour still happens.

[thomasmars]

Hi, this is an issue with the implementation of Fill in the Blanks' getXAPIData() function/contract and the xAPI specification. When there are many alternatives for each blank generating the xAPI statement becomes exponentially big. This manifests in Moodle since it is the only platform that calls the getXAPIData() contract to generate reports. Please move this issue to the Blanks repository, as that is the library that has to change its' implementation of getXAPIData() in order to not crash. Thanks.

[mgancarzdsi]

Thank you for the quick reply Thomas. Moved it over