Microsoft has released a Community Technology Preview (CTP) of the upcoming Service Pack 1 for its SQL Server 2005 database.

The company said that new features in SP1 will include full database mirroring to offer real-time data backups and SQL Server Management Studio Express, which is designed to help database administrators run the free version of SQL Server 2005. SP1 is on schedule for final release next month.

This is the first CTP ever released for SQL Server or its Service Packs. Microsoft, which has traditionally released between one and three beta versions of a software product before its final release, has moved towards CTPs - which arrive very two to three months - for certain products, including SQL Server, Visual Studio and the client version of the Windows operating system, said lya Bukshteyn, Microsoft's director of product management for SQL Server

He acknowledged that Microsoft was partially inspired by the success of the open-source model of software development. "The thing that is very powerful is being open and transparent with the community," Bukshteyn said.

More than 50 companies are already using SQL Server's database mirroring, which was available in the initial release of SQL Server 2005 in November. It was not considered production-ready at that time.

SP1, which is about 250MB in size includes fixes for bugs and other technical problems but no security updates this time around, Bukshteyn said. Security patches for SQL Server will in the future be available on an immediate, ad hoc basis as well as in the Service Packs.

Microsoft has not publicly discussed how well SQL Server 2005, which took five years to ship, is selling -- apart from revealing late last month that SQL Server revenue from its most recent quarter had grown 20 percent over the same quarter a year earlier.