Businesses often need to find nearest points to Points of Interest (POI).
For example, use Yelp to find restaurants within 10 mile distance. As a normal GIS practice, we solve this problem by using the GIS functions. There are lots of Q&As here on this topic and examples are:
I wonder how about in the real business world, when data cannot fit in memory and high computational efficiency is a must.
How does Yelp solve these kind of spatial problem in their work?
Perhaps they use PostGIS, QGIS functions, etc to find nearest points near POI, or maybe they develop their own tools.