MySQL Performance
It’s a shame banks aren’t as open as Twitter and PayPal 
itnews articles on PayPal offer a glimpse on the size/performance of the MySQL installations at both Twitter and now PayPal.
Twitter uses MySQL as a “building block,” he said, “as a core of features we understand and functionality we trust”, upon which his team uses Gizzard for sharding and replication, InnoDB as its storage system, and a NoSQL database called FlockDB.
