NASDAQ has replaced aging Tandem mainframes used to disseminate market data with Microsoft SQL Server 2005 running on the Microsoft Windows Server 2003 Enterprise Edition operating system. The system runs on two 4-node Dell PowerEdge 6850 clusters.

The system supports NASDAQ’s Market Data Dissemination System (MDDS). Every trade that is processed in the NASDAQ marketplace goes through MDDS, and MDDS keeps the official daily record of all trades. To support MDDS, SQL Server 2005 handles approximately 5,000 transactions per second at market open.

The system also simultaneously handles about 100,000 queries a day using the SQL Server 2005 “Snapshot Isolation” feature – a feature that allows real-time queries against the data without slowing the database. NASDAQ identified Snapshot Isolation as a key benefit early on.

“We saw an early demonstration of Snapshot Isolation and knew this was the solution we needed to run queries against real-time data without slowing the delivery of trading data. It has worked perfectly for us,” said Ken Richmond, vice president for software engineering, market information systems at NASDAQ.

Snapshot Isolation works by allowing multiple users to view data concurrently without “locking” other users out of it. It uses a temporary database that holds updated data for each transaction.

Meanwhile, Richmond also noted that the system is cutting costs in comparison to the Tandem Enscribe system that it replaced.

“Ten years ago NASDAQ earned about one penny per trade. Today we make about one-tenth of a penny per trade. SQL Server 2005 is helping us meet our goals of offering our customers more while charging them less,” he said. Richmond called reducing costs one of the “primary drivers” for the project.

The SQL Server 2005 development tools have also cut developers’ time in creating and customizing new solutions, he said, in part through simplified testing and debugging. A recent project that would have been “exceedingly difficult” with the old system took just three or four days.

Mission critical implementations like NASDAQ’s MDDS are giving Microsoft traction in the database race against IBM and Oracle. In 2004 (before SQL Server 2005’s official launch), Microsoft led database vendors in terms of growth of market share, with 18 percent growth over 2003, according to Gartner. Gartner’s numbers for 2005 are not yet available.