Caching location based data?

[Josh Berkus]

John,

> Our site is custom written PHP and MySQL. We use memcache extensively to
> cache many of our SQL queries. I’m wondering if anyone can think of a
> more elegant solution then the one we have devised.

Out of curiosity, why aren't you using PostGIS?   It has special indexing 
types for the sort of query you mention.   While not as fast as memcached, if 
you can keep those indexes in memory they are < 50ms to return a lot of 
queries.

At some point I'll also post a proof-of-concept for the db-based invalidation 
technique I'm using for one project which can get around the regex 
invalidation not being implemented yet.

-- 
Josh Berkus
PostgreSQL @ Sun
San Francisco