Topic
dynamodb
4 articles across 4 sub-topics
Sub-topic
1 article
NoSQL Partitioning: How Cassandra, DynamoDB, and MongoDB Split Data
TLDR: Every NoSQL database hides a partitioning engine behind a deceptively simple API. Cassandra uses a consistent hashing ring where a Murmur3 hash of your partition key selects a node — virtual nodes (vnodes) make rebalancing smooth. DynamoDB mana...
Sub-topic
1 article
Change Feed vs Change Stream: CDC Internals, Reliability, and When to Avoid Each
In the summer of 2023, the platform team at a fast-growing e-commerce company was handling 100,000 orders per day across three microservices: Order Service, Inventory Service, and Billing Service. All three needed to react to the same database mutati...
Sub-topic
1 article
ACID Transactions in Distributed Databases: DynamoDB, Cosmos DB, and Spanner Compared
TLDR: ACID transactions in distributed databases are not equal. DynamoDB provides multi-item atomicity scoped to 25 items using two-phase commit with a coordinator item, but only within a single region. Cosmos DB wraps partition-scoped operations ins...
Sub-topic
1 article
The Dual Write Problem in NoSQL: MongoDB, DynamoDB, and Cassandra
TLDR: NoSQL databases trade cross-entity atomicity for scale — and every database draws that atomicity boundary in a different place. MongoDB's boundary is the document (pre-4.0) or the replica set (4.0+ multi-doc transactions). DynamoDB's boundary i...