It’s called the Online Schema Change for MySQL. Facebook open sourced it this week. What OSC does it allows the social networking company to update its massive MySQL database schema on-the-fly.
The Register’s Cade Metz has the story.
“In the past, according Facebook MySQL guru Mark Callaghan, the company needed a good six months to roll index updates across its sea of MySQL servers. Now, it needs no more than a few days. ‘This lets us make schema changes much, much faster,’ Callaghan tells The Register. ‘And the benefit from the changes is that database queries will be faster.'”