Oracle Executive Chairman Larry Ellison at Oracle Open World '16 Julie Bort/Business Insider Larry Ellison used most of his hour-long keynote session slot at this week's Oracle Open World conference in San Francisco to trash Amazon and its $10 billion Amazon Web Services cloud computing platform.

Amazon has emerged as an unlikely rival to Oracle, poaching loads of database customers over to Amazon Web Services.

Today, Ellison fired back by detailing in great depth all the ways in which the upgraded, "second generation" Oracle Cloud, announced this week, purportedly beats Amazon Web Services.

"Amazon Web Services uses slow first-generation cloud infrastructure," Ellison says.

Chief among Ellison's criticisms of Amazon Web Services:

Amazon is slower: According to benchmark tests the company says will soon to be published on its website, Amazon is 24 times slower than the Oracle Cloud at running Oracle databases. He challenged Amazon to produce better results, saying " if they can beat them, we'll put Amazon's result in."

According to benchmark tests the company says will soon to be published on its website, Amazon is 24 times slower than the Oracle Cloud at running Oracle databases. He challenged Amazon to produce better results, saying " Amazon's tech is out of date: Ellison says the comparison gets worse when you're using Amazon's home-grown Redshift and Aurora database products. "Why is Amazon Redshift so slow? Because it's 20 years behind Oracle," Ellison says. He says that Amazon's database products lack simple, basic features that have been common to Oracle technology since the 1980s and 90s, and they pay for it in performance.

Ellison says the comparison gets worse when you're using Amazon's home-grown Redshift and Aurora database products. "Why is Amazon Redshift so slow? Because it's 20 years behind Oracle," Ellison says. He says that Amazon's database products lack simple, basic features that have been common to Oracle technology since the 1980s and 90s, and they pay for it in performance. Amazon is " more closed than an IBM mainframe:" Because Oracle's database products are available from the Oracle Cloud, the Microsoft Azure cloud, Amazon Web Services, or in a customer's own data center, you have a lot of choice over where and how to use them. Meanwhile, if you want to use Amazon's database products, you have to use Amazon Web Services – which could end up locking you in to using them forever. "I'm not sure that many people will think that's a good idea," Ellison says.

"You know when I'm talking about Amazon, I'm being nothing but fair. You can count on that," Ellison says. "It's just true."

Larry Ellison at Oracle Open World '16 Julie Bort/Business Insider

It wasn't all negative: Ellison also showed off some of the design thinking that went into the next-generation Oracle cloud. He's promoting it as the low-cost, high-reliability alternative to Amazon Web Services for developers of all shapes and sizes to use to build and host their apps.

But it's clear that Amazon's shadow is hanging heavy over Oracle, which is redoubling its efforts to compete in the cloud, even as its long-time rival Microsoft establishes a solid niche for itself as the #2 player and the cloud of choice in the enterprise.

Still, while Ellison is as enthusiastic as ever, analysts are skeptical of Oracle's ability to truly be competitive in this fast-growing market.