Elasticsearch started life as a document database sitting atop the Lucene text search engine library ... application metrics from Microsoft SQL Server, MySQL, PostgreSQL, and other sources.

Custom proximity search is a new feature introduced in SQL Server 2012 Full-Text Search. It's facilitated using the NEAR operator, allowing it to be used in the CONTAINS predicate or CONTAINSTABLE ...

and distributed cousin Elasticsearch’], but with the structure and querying ease of SQL.” The idea is to provide more than a full-text search system. CrateDB’s use cases include big data ...