MongoDB to MySQL the How and the Why by Sarah Mei

Diaspora is the crowd-funded open-source decentralized social network built on Rails. Full buzzword compliance: on by default. We have many thousands of active users and they generate a lot of social data. But after nine months of full-time development with MongoDB as our primary storage engine, a few months ago we converted it all to MySQL. Wait...what? Most people are going the other way, dropping Mongo into a project in place of MySQL or PostgreSQL. Plus, conventional wisdom says that social data is ill-suited to a traditional data store. Come hear a story about a large-scale Rails project that tried it both ways. You'll see crisis and redemption, facts and figures, nerds, kittens, ponycorns, and, of course, the secret sauce. Hecklers will be piped to /dev/null.

[digerpaji]

The table leg problem has one connection...multiple dimensions of relations become a problem

[shivpratap]

Hi mam. . why mongodb faster than mysql ? please give me answer.

[digerpaji]

You speak wisdom lady, but even though facebook uses mysql they still don't do joins....they pull in the data individually in their app and then join it using application login, because CPU is cheap Database time is expensive.

Much appreciate the knowledge.

[SamITNY]

Social data isn't relational? Seriously?

If a table has four legs, are those legs related to that table?

Is a comment on an article related to it?

Just because *some* people (myself included) have decided to REPRESENT real-life information in a non-relational manner, it doesn't make the data non-relational. It just means we have other priorities such as speed, or possibly, we just like to complicate things for no apparent reason.

Non-relational data? Nah, it's an incomplete representation.