Solid Information Technology, which makes embedded databases that are widely used in telecommunications equipment, Monday announced plans to release an open-source version of its core storage engine that is compatible with the popular MySQL database.

Solid will make a prototype of its online transaction processing storage engine, solidDB, available for download next Monday. The release coincides with the start of MySQL's annual user conference in Santa Clara, California.

So far, solidDB has been deployed 3 million times, according to Paola Lubet, vice president for marketing and business development. It has mostly been embedded in telecom and networking hardware from companies such as Siemens, Nortel Networks and Cisco Systems, as well as in the OpenView monitoring software from Hewlett-Packard. But Lubet said the software is being used by 120 enterprise customers, including, among others, financial firms that use solidDB for handling live trading data.

The popular open-source MySQL database allows users to choose different methods for storing data. MyISAM is the default storage engine, but many users choose to use another bundled engine, InnoDB, which is seen as more reliable and faster for many scenarios.

InnoDB's parent company, Innobase OY, was bought by Oracle last October. That sparked fears that Oracle might use its ownership of InnoDB technology to hurt MySQL. That hasn't happened, although Oracle tried unsuccessfully to buy MySQL.

MySQL renewed its contract for Oracle to continue supporting Innobase in early April, though it is developing its own storage engine.

Lubet claimed that SolidDB boasts a finer pedigree than InnoDB.

"InnoDB is a good product, but it's basically only been tested on Web servers. We come from mission-critical environments," Lubet said. Features in Solid such as multiversion concurrency, which minimizes data tie-ups, the ability to set database roles for quicker security implementation and the ability to change a database configuration without shutting the database down also distinguish Solid from InnoDB, Lubet said.

Solid will release a beta version of the source code of the solidDB Storage Engine under the GNU Public License in July. The software is set for final release in the fourth quarter.

Lubet said the company will disclose prices for commercial support at the MySQL conference.