Interesting, how long ago was that? I would be curious to know if the WiredTiger switch ever happened, and what that support relationship looks like not given the contentious relationship between MongoDB and AWS. The old Wired Tiger Inc website[1] still lists AWS as a customer.
Then again, the relationship between AWS and Oracle is even more contentious and Aurora MySQL is one of AWS's most popular products so I don't think they are terribly worried about building on competitor's technologies.
3+ years ago, so it's entirely possible that things have changed since I left. I don't have any more recent information on the state of the system.
At least when I was there, the strong focus was always on adding new features (global & local secondary indexes, change streams, cross-region replication, and so on) to keep up with the Joneses (MongoDB et al).
Meanwhile, a bunch of internal Amazon teams were taking a dependency on it instead of being their own DBAs, and those teams didn't care that much about the whiz-bang features, they just wanted a reliable scale-out datastore that someone else would get paged about when some component failed.
Adding features at a breakneck pace while keeping up umpteen-nines reliability and handful-of-milliseconds performance meant tech debt and non-user-facing improvements, including WiredTiger, all got sidelined. Around the time I left, our page load was around 200 per week. That's one page every 50 minutes, 24/7, if you're keeping score at home.
Given the scale and popularity of DynamoDB and the distributed nature you would think that they could hire multiple teams just to work on improving it, but I guess it isn't as simple as that.
I would love to get a behind the scenes look at the process of gradually improving the components of DynamoDB with better technologies, while still maintaining reliability and performance.
Then again, the relationship between AWS and Oracle is even more contentious and Aurora MySQL is one of AWS's most popular products so I don't think they are terribly worried about building on competitor's technologies.
1. http://www.wiredtiger.com/