The chief executives of Oracle and Salesforce.com traded more blows on Thursday, this time arguing over the core tenets of cloud computing.
It came as the latest scrap in a battle that had led to the cancellation of a keynote by Salesforce.com founder Marc Benioff at Oracle's OpenWorld conference.
Oracle used the conference to announce the launch of a competing cloud product, Oracle Public Cloud and separate social network facing off against Salesforce.com's Chatter.
The company said the Oracle Public Cloud would provide platform-as-a-service and software-as-a-service, both intended to ease migration of existing Oracle customers to the vendor's long-promised 'Fusion' set of applications.
Compatible On-Demand Fusion applications would include customer relationship management, human capital management, talent management and financials.
They would be available via a monthly subscription, along with a database migration service, Java platform, data subscription service and service-oriented architecture solution.
The services would initially be served out of Oracle's US data centres, built off its Exalogic and Exadata appliances.
But Ellison used the announcement primarily to slag Salesforce.com, claiming his rival had failed to meet industry standards.
"Beware of false clouds - that is such good advice," he told attendees, borrowing the tagline used by rival Salesforce.com chief Marc Benioff in previous back-and-forths.
Ellison argued Salesforce.com's cloud was "stickier than a roach motel" that offered vendor lock-in rather than open, industry-based standards.
"There is a huge difference between clouds and false clouds. Our cloud is based on industry standards... but Salesforce; well if you want Apex, the only place you can get it is Salesforce."
Benioff maintained in a keynote earlier that day that Salesforce.com was based on key tenets of data portability and open application programming interfaces.
Arguments between the two extended to the notion of multi-tenancy.
Though Oracle's service offering was dubbed a "public cloud", it provided separate virtual machines and databases to individual customers based on precedent, Ellison said.
"We wrote the database, we think [multi-tenancy] is a really bad idea," he said.
Benioff had argued, hours earlier, that multi-tenancy was "the future of our industry" and a must-have for new cloud operations to maintain efficiency of services.
"When you create a new account at a bank, they don't create a new server for you," he said. "They're using a shared database to save your money.
"The proof point is Facebook; what would it take to deliver that on a case-by-case basis to all those users?"
He argued insistence on single tenancy only played to Oracle coffers.
"Single tenancy goes hand in hand with those proprietary mainframes," Benioff said. "That's what Larry wants [customers] to buy because that's the best thing for Oracle."
Benioff claimed in his keynote - before Oracle's cloud announcement - that Ellison was a champion of the cloud, as proved through his early investment in Salesforce.com and ongoing involvement with multi-tenanted cloud provider NetSuite.
Though Oracle had provided only small glimpses of an actual cloud offering to date, its announcement today was the first time it planned a full cloud compute for public use.
"[Ellison] believes in this model but he also believes that he cannot sell this model at his conference because there's no money for Oracle in this model," Benioff said.
"He's actually a huge believer in our model - that's the great irony of it all."