IBM is buying database company Solid Information Technology, a close partner of IBM rival MySQL.
Solid makes an embedded database with an in-memory database engine, which means it can store and retrieve data from main memory, giving faster performance than traditional disk-based systems.
That makes it popular for applications that require very fast processing times, such as routing calls in a phone network or trading stocks. Solid's customers include Cisco, Siemens, TeliaSonera and Nokia.
IBM expected the deal to be closed in the first quarter of 2008. It said the deal would enhance its database line-up by adding real-time data access capabilities.
The IBM acquisition may be seen as a setback for MySQL, since it marks the loss of independence of another company that makes a high-performance transaction engine for MySQL's database.
Two years ago Oracle bought Innobase, which made the most popular MySQL transaction engine. Oracle continues to license InnoDB to MySQL, but the acquisition prompted MySQL to look for alternatives.
One of those was Solid, which joined MySQL's storage engine certification program and released an open source version of its database engine for MySQL.
However, MySQL is also developing its own transaction engine, so in the long term it will be less dependant on partners. Called Falcon, the engine is due to ship with MySQL 6.0, which is due for wide release late next year.