Xapian and Sphinx are two unrelated standalone search technologies written in C++. This chapter will explain how Xapian supports real time indexing and exposes extremely flexible APIs, while Sphinx offers lightening fast search performance. It will also explore using the Java based Solr search engine, discussing the steeper requirements and its flexible, advanced feature set. This chapter will detail how each solution can be integrated into a Drupal website, replacing or enhancing Drupal's core search functionality.

1. Xapian
   1. Background
   2. Strengths
   3. Weaknesses
   4. Benchmarks
   5. Integration
2. Sphinx
   1. Background
   2. Strengths
   3. Weaknesses
   4. Benchmarks
   5. Integration
3. Solr
   1. Background
   2. Strengths
   3. Weaknesses
   4. Benchmarks
   5. Integration