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We wrote some App Engine code to do geospatial lookups.

Before anyone gets the idea that the links in the parent are worth trying, they're not: the performance is absolutely atrocious – on our data set, 13 seconds per lookup.

We wrote our own approach on App Engine and now get stable performance on our datasets at ~300ms per lookup.

(We're doing Foursquare-type lookups.)

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I can't imagine how an indexed query on a List<String> of ~10 items takes 13 seconds.

'We wrote our own approach on App Engine'

Hmm... details?

You can find the code we wrote here, along with the testing infrastructure:

https://github.com/erichocean/appengine-geospatial-lookups

Like Foursquare, mobile clients send their current location, plus a search radius, and App Engine code returns a result set ordered by distance.

We were getting query times with realistic data set sizes in the ~13 second range from the code you linked to. With the code above, we're ~40x faster. YMMV.

You should write this up somewhere and post it to HN and the App Engine Reddit. Getting geospatial right is hard, and it sounds like you've done a good job.

That's awesome. How does it work, basically?

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