> We were now rendering our site index in 1.5 seconds or less, compared to 3 seconds before.
This is the real WTF. What kind of queries take three seconds to run, that is ridiculous. Even with indexes 1.5 seconds is insane.
Deciding against premature optimisation isn't permission to throw away good, efficient design. It's clear from the rest of the article that these guys really have no idea what they're doing. Quoting the results of all their optimisations:
> In the end, we did not go down. The last round of load tests with httperf showed us handling 200 GETs a second indefinitely, with an average response time of about 1.2 seconds. We served thousands of requests without even a hiccup, and we did it without spending any money.
This is really poor performance, and it shows in the site when you change page or select a different category/filter. I'm guessing that they also chose a nosql solution for the wrong reasons, as it seems everything there could be done much faster/better by using an ACID compliant database.