Last year the company announced that both its back-end message queue and Tweet storage had been re-written in Scala, and in the spring of 2010 the search team at Twitter started to rewrite the search engine. As part of the effort, Twitter changed the search storage from MySQL to a real-time version of Lucene. More recently the team announced that they were replacing the Ruby on Rails front-end for search with a Java server they called Blender. This change resulted in a 3x drop in search latencies.
via infoq.com
