Dive Brief:

• Amazon is about 92% finished migrating off of Oracle's database software and onto its internal Aurora PostgreSQL, according to Werner Vogels, Amazon CTO, in a Tweet Wednesday.
• Vogels took to Twitter to correct what he called an erroneous report from CNBC. An Amazon warehouse in Ohio experienced the creation of too many savepoints, resulting in a "temporary situation where the database was very slow," according to Vogels.
• The Ohio warehouse had been one of the locations to migrate off of Oracle and "despite that team knowing that Aurora and Oracle handle savepoints different," the application experienced "intermittent timeouts," he said.

Dive Insight:

Vogels tweet opens up a broader narrative around the difficulty of database migration. The process requires risk and disruption in database migration and every detail has to be precalculated.

Amazon is operating at a scale that no one has "ever even come close to," said Rick Greenwald, senior director analyst at Gartner, in an interview with CIO Dive, and is probably better equipped to handle a migration than anyone else in the world.

Yet it hit a snag.

"If Amazon is having a problem," said Greenwald, "you can pretty much say everyone is having a problem." The biggest mistake companies make when contemplating a database migration is concluding all databases are generic.

Snags occur in database migration when a company uses a database platform, but not the features that make it special. When they eventually start using those unique features on another database, problems arise.

One type of database may handle locking well. But if a company moves databases and the way that database implements its locking feature internally is different, it can be disorienting for the user.

The "things you took for granted have changed," said Greenwald. This was likely the case for the differences in Oracle and Aurora's savepoints management.

In Amazon's case, the way Aurora handles savepoints isn't inferior to Oracle's, it's just different. Ultimately, it's nearly impossible for any piece of database software, "which is the most complex software ever written," to be completely bug-free, said Greenwald.

Oracle has dominated the database market for decades, and CTO Larry Ellison is quick to remind Amazon that. And veteran players are better equipped at handling nuances in database migration, making them more robust.