I checked the link to the digg case myself, and then I found this:
Computing the intersection with a JOIN is much too slow in MySQL, so we have to do it in PHP.
If they claim that doing any heavy computation is faster in PHP than in MySQL they are obviously 100% incompetent at dealing with databases. And I say that as someone generally laughing at MySQL compared to other database-engines. They actually prove this in their explanation:
Query Friends for all my friends. With a cold cache, this takes around 1.5 seconds to complete.
With proper indexes this should take 100ms at most.
Not saying that non-relational databases don't have uses, but every single case I've seen the specifics of where a NoSQL solution is proposed as a better alternative with regard to performance and scalability has so far been rooted in incompetence. Make of that what you like.
Computing the intersection with a JOIN is much too slow in MySQL, so we have to do it in PHP.
If they claim that doing any heavy computation is faster in PHP than in MySQL they are obviously 100% incompetent at dealing with databases. And I say that as someone generally laughing at MySQL compared to other database-engines. They actually prove this in their explanation:
Query Friends for all my friends. With a cold cache, this takes around 1.5 seconds to complete.
With proper indexes this should take 100ms at most.
Not saying that non-relational databases don't have uses, but every single case I've seen the specifics of where a NoSQL solution is proposed as a better alternative with regard to performance and scalability has so far been rooted in incompetence. Make of that what you like.