Microsoft on Thursday announced that it acquired Citus Data, a startup that has commercialized the open-source database software called PostgreSQL. The terms of the deal weren't disclosed.

The deal will help Microsoft support open-source technologies, particularly in the cloud, while continuing to make money from popular proprietary software like Windows and Office. In the cloud business, Microsoft wants to use openness as a way to pick up business amid competition from Google, market leader Amazon and others.

"Together, Microsoft and Citus Data will further unlock the power of data, enabling customers to scale complex multi-tenant SaaS applications and accelerate the time to insight with real-time analytics over billions of rows, all with the familiar PostgreSQL tools developers know and love," Microsoft said in a statement.

"I am incredibly excited to welcome the high-caliber Citus Data team to Microsoft! Working together, we will accelerate the delivery of key, enterprise-ready features from Azure to PostgreSQL and enable critical PostgreSQL workloads to run on Azure with confidence," Azure Data Corporate Vice President Rohan Kumar was quoted as saying in the statement. The startup was founded in 2011 and had offices in San Francisco and Turkey, with 40 employees, according to LinkedIn data. Citus Data's investors include Silicon Valley accelerator Y Combinator, Data Collective and Khosla Ventures.