Since 2005, Oracle has spent at least US$32 billion on acquisitions -- turning itself into the vendor of a top-to-bottom enterprise software stack that is arguably broader in scope than any rival suite.

In doing so, Oracle hasn't diluted its database focus. Sales of databases and middleware still account for more than half of its revenue. And according to consulting firm Gartner, Oracle controlled 49 percent of the global database market last year, with more revenue than the next four vendors -- IBM, Microsoft, Teradata and Sybase -- combined.

But Oracle has shown some signs of vulnerability at the high end of the database market. For instance, many Web 2.0 companies are eschewing its databases and instead running open-source technologies such as MySQL on grids of PC servers. And corporate users with data warehouses sized in the hundreds of terabytes, or even in the petabyte range, are finding column-oriented databases and specially tuned data warehousing appliances to be more scalable than Oracle databases are.

So Oracle's annual OpenWorld conference in San Francisco two weeks ago was heavy on database news, as the company tried to show that it is agile enough -- and its software is robust enough -- to respond to the new challengers.

At the top of the list was Oracle's announcement of a pair of hardware products -- its first ever -- aimed at users looking to get ultrafast performance out of their ultralarge databases.

For the past six months, Oracle CEO Larry Ellison had teased users and analysts with hints that the vendor would introduce a "database accelerator" at OpenWorld. That turned out to be the Exadata Storage Server, which combines Oracle's parallel query software with ProLiant servers from development partner Hewlett-Packard.

What makes the Exadata system different from a typical storage server, according to Oracle, is the database intelligence built into the device. Ellison claimed that Exadata can speed up large queries by performing lower-level calculations on the information it stores and then sending the results to the main database, instead of flooding it with raw data.

The other new product, the industrial-sounding HP Oracle Database Machine, is a self-contained system designed to match up against integrated data warehousing appliances from vendors such as Teradata and Netezza Inc.

The Database Machine combines eight regular database servers running Oracle Database 11g with 14 Exadata systems that have a total storage capacity of 168TB and InfiniBand connections offering 14GB/sec. of aggregate data bandwidth.