Amazon DynamoDB adaptive capacity now handles imbalanced workloads better by isolating frequently accessed items automatically. If your application drives disproportionately high traffic to one or more items, DynamoDB will rebalance your partitions such that frequently accessed items do not reside on the same partition. This latest enhancement helps you maintain uninterrupted performance for your workloads. In addition, it helps you reduce costs by enabling you to provision throughput capacity more efficiently, instead of overprovisioning to accommodate uneven data access patterns.
from Recent Announcements: https://aws.amazon.com/about-aws/whats-new/2019/11/amazon-dynamodb-adaptive-capacity-now-handles-imbalanced-workloads-better-by-isolating-frequently-accessed-items-automatically/