[zachster]

Thanks for the pointer! This looks interesting. The edge conditions seem like they might pose a problem. I'll have to check out how often it would occur. Maybe the geospatial indexes are a better bet. It looks like MongoDB supports them also. Good excuse to try that out.

[bravo_sierra]

The edge cases happen all the time.

Using a B-Tree on a Geohash (like MongoDB does) is a bit more efficient that just indexing min/max values, but not by much. MySQL, PostgreSQL and even SQLite have R-Tree indices that perform 10x better.

[nl]

If you are prepared to introduce new technology specifically to solve this problem, then you should take a look at LocalLucene, too: http://www.gissearch.com/locallucene

[thibaut_barrere]

I've been using either MySQL with Sphinx or MongoDB with the built-in geonear successfully.

If you're already using MongoDB, it's really dead-easy to setup (see the docs).