One fun thing: this was my first time playing with the new DynamoDB on-demand capacity features. If you do run the code, check out the CloudWatch metrics on the table. It's pretty cool to see the WCUs shoot up to 150 and back down to 0 with no throttling whatsoever.
I have a dynamo addon for Heroku apps and need to keep cost under control. I use AWS Budgets and put a fixed price monthly budget on every table. If users go over the budgets access keys get disabled.
They initially implemented capacity units to be spread evenly at the partition level and now they have finally implemented it to work at the table level (which is how they sell it and how they talk about it).
Big whoop, you still have to ask daddy if you want to write at more than 80MB/s per account.
Normally, you just write to a data store until it's done. The faster the disks the less time it takes.
Now, writes can "fail" so you need to wait/retry or put it back on a queue to reprocess when you have write units available (both of those and the associated logging will cost you $ on AWS).