CrateDB is described as 'open source SQL database with a ground-breaking distributed design: Uses SQL to process any type of data, structured or unstructured, Performs distributed SQL queries at realtime speed, even JOINs and aggregates Makes scaling simple Customers often use' and is an app in the Development category. There are more than 10 alternatives to CrateDB for a variety of platforms, including Windows, Linux, Mac, BSD and SaaS. The best alternative is PostgreSQL, which is both free and Open Source. Other great apps like CrateDB are MongoDB (Free), MySQL Community Edition (Free, Open Source), MariaDB (Free, Open Source) and Firebird (Free, Open Source).
PostgreSQL is a powerful, open source object-relational database system. It has more than 15 years of active development and a proven architecture that has earned it a strong reputation for reliability, data integrity, and correctness.
MongoDB is a document database with the scalability and flexibility that you want with the querying and indexing that you need MongoDB stores data in flexible, JSON-like documents, meaning fields can vary from document to document and data structure can be changed over...
MariaDB is a backward compatible, drop-in replacement of the MySQL® Database Server. It includes all major open source storage engines. The source code for MariaDB is publically available from Launchpad. Binaries and packages are also available.
Firebird is a relational database offering many ANSI SQL-92 features that runs on Linux, Windows, and a variety of Unix platforms. Firebird offers excellent concurrency, high performance, and powerful language support for stored procedures and triggers.
Percona Server is an enhanced, drop-in MySQL® replacement which has been downloaded more than 1,400,000 times. Percona Server is based on the Percona XtraDB Storage Engine, an enhanced version of the InnoDB storage engine for MySQL and MariaDB.