It looks like the references you are linking here are obsolete, there are no direct links to them from the Mongoose OS docs.
You can use mgos_dash_notifyf to send the data you want to analyse to mDash. Later on, you can download the database and process it with your own application.
unsigned long heap_free = mgos_get_free_heap_size();
unsigned long heap_min_free = mgos_get_min_free_heap_size();
/* later in the code */
mgos_dash_notifyf("DB.Save",
"{timestamp:%lu,heap_free:%lu,heap_min_free:%lu}",
time(NULL), heap_free, heap_min_free);
Results:
timestamp device_id topic message
2021-06-29 12:40:05 device33 data {"timestamp":1624970405,"heap_free":42168,"heap_min_free":26456}
2021-06-29 12:39:05 device33 data {"timestamp":1624970345,"heap_free":42168,"heap_min_free":26456}
2021-06-29 12:38:05 device33 data {"timestamp":1624970285,"heap_free":42168,"heap_min_free":26456}
2021-06-29 12:37:05 device33 data {"timestamp":1624970225,"heap_free":42168,"heap_min_free":26456}
2021-06-29 12:36:05 device33 data {"timestamp":1624970165,"heap_free":42168,"heap_min_free":26456}
2021-06-29 12:35:05 device33 data {"timestamp":1624970105,"heap_free":42168,"heap_min_free":26456}
2021-06-29 12:34:05 device33 data {"timestamp":1624970045,"heap_free":42168,"heap_min_free":26456}