One of the best ways to improve both the speed, and relevancy, of search results for a Drupal site is to stop using the Drupal core search module and start using Apache Solr. Solr is a Java-based application that provides an API for interacting with Apache Lucene via HTTP to facilitate the creation of excellent applications for performing full-text content searches, with a special focus on internet-based search applications. The quick pitch for why you should use Solr is it's insanely fast, especially when compared with Drupal's default Search module, and it can be scaled to handle millions of search queries per second and huge piles of data.
Since Solr is a third party application we need a way to bridge the gap between Solr and Drupal. Really, there are two parts to this puzzle: getting the data out of Drupal and into Solr so it can be processed and indexed, and passing a search query from Drupal to Solr in order to retrieve, and display, search results. For that, we'll use the Search API module, and the Search API Solr module.
In order to demonstrate a real-world use case we'll pretend that we're the owner of a website that contains a database of fish species. As the database has grown over time we've begun to feel the limits of Drupal's MySQL full-text search and want to improve our search tools. Using Solr will allow for better matches in full-text search, faster searches, and a lot of additional functionality like partial word matches, spell checking, facets, and more.
In this series we'll cover:
- What Apache Solr is and why you should consider using it
- Installing Solr and configuring it to work well with Drupal content
- The contributed Search API module
- The contributed Search API Solr module
- Configuring Drupal to send content to Solr for indexing
- Retrieving search results from Solr and displaying them in Drupal on both a stand-alone page and with the Views module
- Using Solr field boosting to influence result relevancy
- Using the contributed Facet API module with Solr to allow for faceted search results
- Configuring stop words, synonyms, and promoted search results in Solr
This series is for anyone that wants to improve the quality of the search functionality of their Drupal-powered site. There is some system administration required to install Solr, but it's pretty straightforward. Almost everything else is done via configuration in Drupal's, or Solr's, user interface and by editing simple XML configuration files. So, no PHP, or module development experience required. We do however assume that you're already familiar with basic Drupal administration.