In this chapter, we mainly concentrated on different techniques to optimize Solr's performance. We started with understanding the various performance factors responsible for Solr's performance and covered vital concepts such as how to replicate an index in a master-slave architecture, and learned more about implementing different Solr-caching techniques such as document caching, query result caching, filter caching, and finally how to cache the whole result page. We also understood SolrCloud and how to perform various activities based on performance optimization, such as creating a SolrCloud cluster, having more than one collection in a SolrCloud cluster, and managing the SolrCloud cluster that you have created or those that already exist. Additionally, we learned how to play around with distributed indexing and searching, which are automated activities carried out on the documents, and how to stop automatic document distribution based on the certain scenarios. By the end of the...