how to efficiently perform bounded geo query?

Any suggestions for how to efficiently perform bounded geo query? caching?

Background

I am using google maps 开发者_如何转开发+ marker clusterer, and every time user changes bounds I query the backend. I would like to make this more efficient.

Options

1. No Caching - on bounds change -> query with new bounds -> update all markers
2. Caching on bounds change -> divide the bounds into quadkeys -> check the quadkey cache -> query for markers using quadkey not in cache -> add new quadkey markers to the map

Suggestions please?