Solr 4.0 dramatically improves scalability, performance, and flexibility. An overhauled Lucene underneath sports near real-time (NRT) capabilities allowing indexed documents to be rapidly visible and searchable. Lucene’s improvements also include pluggable scoring, much faster fuzzy and wildcard querying, and vastly improved memory usage. These Lucene improvements automatically make Solr much better, and Solr magnifies these advances with “SolrCloud.” SolrCloud enables highly available and fault tolerant clusters for large scale distributed indexing and searching. There are many other changes that will be surveyed as well. This talk will cover these improvements in detail, comparing and contrasting to previous versions of Solr.