In this chapter, we understood how an advertising network works. We went through the implementation of Solr for a large-scale ad distribution network. We saw the problems plaguing such an implementation in an advertising network and the solutions to these problems. We also saw the architecture of a large-scale Solr system. We saw the cache optimization options in Solr. We also built a plugin that interacts with Redis to aid the real-time update of the status of ads.

In the next chapter, we will explore a framework known as AJAX Solr, which can be used to execute queries on Solr directly from the client browser without the need for any application.