Thank you all for your replies!
I think I made a mistake. When I did the test, the schema of Mnesia contains more attributes than SQLite. It should be 10x times slower instead of 100x when iterate Mnesia, while accessing via key is instant.
Having said that, is it better to use SQL when storing data that will probably be queried not only by keys?
What would you use Mnesia for? Storing runtime configurations? Caches?
