At the moment we use QJsonDocument which fails to load somewhat bigger files, s.a. https://stackoverflow.com/questions/22183885/json-parser-that-can-handle-large-input-2-gb

We need to evaluate and switch to other parsers, e.g. RapidJSON:
https://github.com/miloyip/nativejson-benchmark
http://rapidjson.org
https://plus.google.com/+ThiagoMacieira/posts/7EVTACgwtxK