Redis as a preprocessor complement to ElasticSearch
ElasticSearch started off as a JSON-based frontend to Lucene. Lucene is an open source enterprise search index sponsored by the Apache Foundation that is also the core search technology for another popular search-based technology called Solr. ElasticSearch indexes JSON documents into a Lucene index and uses a custom JSON-base DSL (domain specific language) for querying the search index. ElasticSearch uses sharding and clustering techniques for scaling search to include large data sets. ElasticSearch powers searching for a number of well known websites including Netflix, The New York Times, Cisco, eBay, and Goldman Sachs.
The main sponsor of ElasticSearch, the for-profit company Elastic.co, also supports a number of other technologies that complement or build upon the ElasticSearch search index including Logstash, a log harvester that indexes logs into ElasticSearch, and Kibana, a visualization tool for ElasticSearch. Using all three together...