Can open source win big business?

That was the message from some Sun Microsystems and MySQL executives at the MySQL users conference here. Swedish company MySQL develops open-source database software and is making inroads into markets primarily dominated by companies such as Oracle, IBM and Microsoft.

During a keynote speech Friday, Rick Cattell, deputy chief technology officer of software at Sun, said that offering great software doesn't guarantee success in the big-business market.

Chief information officers at companies are "going to be really conservative," Cattell said, adding that businesses aren't going to adopt the latest open-source technology until they see major vendors support and endorse it. The open-source companies also have to make sure that applications are available, he said.

Pursuing open source as an altruistic venture is nice, Cattell said, but "your boss wants to make money, too."

During his presentation, Cattell didn't talk about MySQL specifically, prompting one audience member to ask what Sun's plans were for the database software. He said that Sun already ships MySQL on some Linux machines and is still outlining its strategy for the future.

"We're a big fan of MySQL. I'm a big fan of MySQL," Cattell said. "We think it's great you guys are standing up to Oracle."

Once close allies in their fight against Microsoft, Oracle and Sun have been on a rocky road recently, partly because Oracle has become less dependent on Sun as a major source of an alternative operating system to Microsoft's Windows. Increasingly, Oracle is embracing Linux to fill that role.

Cattell said Sun would soon be releasing low-cost clustered machines with shared memory that will compete effectively with Linux machines for database functions.

The MySQL conference, which runs through Saturday, is MySQL's first users conference. The company unveiled the source code to MySQL 5.0 on Thursday, which it called its first major push into the corporate market.

MySQL CEO Marten Mickos acknowledged that it would take time for big businesses to embrace MySQL in a major way. He predicted that open-source database software will eventually reach a tipping point in terms of adoption by big business, much the same way Linux did. A few years ago, Linux use was primarily an underground software movement taking place behind the backs of company executives. Now, it's a major player in the operating system market, embraced by companies ranging from Oracle to IBM to Intel.

"As long as we are profitable and free, we can wait," Mickos said.

The company said that 4 million people have installed its software worldwide, and 4,000 have paid for it. MySQL has a dual licensing model: People can download it for free if they agree to share any changes to the product, or they also can use a paid version and keep their modifications proprietary. Customers include Google and Yahoo, which use the software to run parts of their Web sites.