Which means we will have 1M leaf nodes and they will be holding 12GB of location data. A QuadTree with 1M leaf nodes will have approximately 1/3rd internal nodes, and each internal node will have 4 pointers (for its children). If each pointer is 8 bytes, then the memory we need to store all internal nodes would be:
1M * 1/3 * 4 * 8 = 10 MB
So, total memory required to hold the whole QuadTree would be 12.01GB. This can easily fit into a modern-day server.
what is the benefit of caching quadtree internal nodes.