NonStop SQL is a relational database product originally produced at Tandem Computers using the pioneering Ingres source code from University of California, Berkeley. NonStop is the "brand name" for Tandem's suite of high-availabiliy products, a brand that survived Tandem's takeover by Compaq, and today after Compaq's takeover by HP. NonStop SQL continues to be offered as a part of this suite today.

History

Jerry Held and Carol Youseffi were both team members on the original Ingres project under Michael Stonebraker, who moved to Tandem in the early 1980s to commercialize the Ingres code. NonStop SQL was a version of Ingres modified to run effectively on parallel computers, adding functionality for distributed data, distributed execution, and distributed transactions (the last being fairly difficult).

First released in 1987, a second version in 1989 added the ability to run queries in parallel, and the product became fairly famous for being one of the few systems that scales almost linearly with the number of processors in the machine: adding a second CPU to an existing NonStop SQL server will almost exactly double its performance. Tandem was later purchased by Compaq who started a re-write in 2000, and now the product is at HP.