Sure, you just need to port filters to the content resolver calls (which look like SQLs if you ever used SQLs in Java). I just don't know if the LMDb idea of mapping file pages to memory works is optimized for android's filesystem.  

 Its a virtual memory thing more than a filesystem thing. Just need to make sure android supports allocating large virtual memory maps. 

 Android is linux, right? I don't see why it wouldn't allow big maps 

 Android exposes the filesystem through it's own interfaces that might get in the way. So, when it comes to file system access, I usually don't assume anything.