Twitter's new search architecture took the company's search gurus about six months to build. They built it on an efficient inverted index rather than a relational database. They chose to start with
Lucene, a search engine library written in Java. More than 1,000 tweets and 12,000 queries per second, equaling more than 1 billion queries per day, put a heavy load on machines, so the new system
must last for several years.
Read the whole story at Twitter Engineering Blog »