Amazon move off Oracle caused Prime Day outage in warehouse

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Amazon founder and Washington Post owner Jeff Bezos speaks during the opening ceremony of the media company’s new location.

Amazon is learning how hard it can be to move off of Oracle’s database software.

On Prime Day, while the e-retailer was dealing with a major website glitch that slowed sales, the company was also dealing with a technical problem in Ohio at one of its biggest warehouses, leading to thousands of delayed package deliveries, according to an internal report obtained by CNBC.

The problem was in large part due to Amazon’s migration from Oracle’s database to its own technology, the documents show. The outage underscores the challenge Amazon faces as it looks to move completely off Oracle’s database by 2020, and how difficult it is to re-create that level of reliability. It also shows that Oracle’s database is more efficient in some aspects than Amazon’s rival software, a point that Oracle will likely emphasize during this week’s annual OpenWorld conference in San Francisco.

Following the Prime Day outage, Amazon engineers filled out a 25-page report, which Amazon calls a correction of error. It’s a standard process that Amazon uses to try to understand why a major incident took place and how to keep it from happening in the future.

The report shows that Amazon struggled to identify the root cause of the Prime Day issue because of a feature it lost after the database was moved over. It also failed to come up with a contingency plan in case of an error in its newly installed database, called Aurora PostgreSQL, the documents show.

In one question, engineers were asked why Amazon’s warehouse database didn’t face the same problem “during the previous peak when it was on Oracle.” They responded by saying that “Oracle and Aurora PostgreSQL are two different [database] technologies” that handle “savepoints” differently.

Savepoints are an important database tool for tracking and recovering individual transactions. On Prime Day, an excessive number of savepoints was created, and Amazon’s Aurora software wasn’t able to handle the pressure, slowing down the overall database performance, the report said.