Solr use cases

Solr is widely accepted and used by big companies such as Netflix, Disney, Instagram, The Guardian, and many more. Let us see with the help of a few use cases the real-life importance that Solr has made on renowned scenarios.

For an extended but incomplete list of use cases and sites that leverage Solr, you can refer to the official web page of Solr at https://wiki.apache.org/solr/PublicServers:

This diagram helps us understand Solr as a solution serving various industries. Though it's not an exhaustive list of industries where Solr has been playing a prominent role in business decisions, let's discuss a few of the industries.

Social media

LinkedIn, a well known professional social media site, uses Lucene/Solr search. Lucene has a powerful faceting system that allows us to pivot and navigate by user or company attributes abstracted from user profile data. LinkedIn has an excellent feature that is backed up by Solr: its ranking of results by people's relationship with you. This data is not fixed, and being derived by Lucene in real time, it's all based on the arithmetic calculations of the relationships in your connections list.

One more use case is Myspace. Myspace is considered one of the world's largest search sites, with almost 200 million active users and adding up to almost 2.5k new users daily. It is expected to have around 50 million videos and adding around 75,000 daily. Myspace consists of almost 900 billion rows of data and 15 billion friend relationship searches by Lucene, with about 1 terabyte of data added every week.

Science and research

NASA (https://www.nasa.gov/open/nebula.html) uses Solr for its Nebula Cloud Computing Platform. Similarly, Public Library of Science (PLOS) that is a non-profit publisher of research articles on various subjects. VUFind (https://vufind.org/vufind/) is another powerful open source discovery portal of libraries. It is known to have around 25 million records for a few of its implementations.

Search engine

Having Google using Solr is a milestone for Solr. Google Search Appliance (GSA), is backed up with Solr. GSA uses many features of Solr: metadata sorting, recommendations, spellcheck, auto-suggest, and more.

Similarly, Open Test Search (http://www.opentestsearch.com/) uses Solr to provide a comparison of a few common search engines.

E-commerce

Flipkart is a leading example of Solr. It has more than 900k users and sees more than 20k searches per second. Flipkart product search has a backbone of 175 million listings, ~250 million documents, and ~5,500 categories. The major challenge was real-time results, ranking, autocompletion, high-update rates, and inverted index. It has become a huge success by using Solr for product searches for its e-commerce business.

Media and entertainment

Netflix uses Solr for the site search feature. Netflix has more than 2 million queries per day for searches and more than 15 million subscribers. It is available in more than 190 countries and supports around 23 languages. The search works based on video title name, genre name, or person name. Features such as autocompletion and ranked results are used by Netflix.

The Guardian, one of the leading newspapers, also uses Solr for its API search platform. There are other users too: MTV, Digg, cnet.com, and many more.

Government

The White House uses Solr for https://www.whitehouse.gov/. It uses features such as search, highlighting, and faceting. Similarly, Federal Communications Commission (FCC) uses Solr for its website search.

Education

Hathitrust is another wonderful use case of Solr. It has almost a couple of terabytes of index, with more than 10 million books provided online. Solr plays a prominent role in searches through its huge library of books. There are many such examples having similar use cases:

• Internet Archive: https://archive.org/
• National Library of Australia: http://trove.nla.gov.au/
• FictFact: https://www.fictfact.com/
• Biblio: https://www.biblio.com/
• A Norwegian online book store: https://www.akademika.no/