Topic
nosql
9 articles across 7 sub-topics
Sub-topic
2 articles
CosmosDB Partition Internals: Logical vs Physical Partitions Explained
🔥 When Your Database Bill Triples Overnight A retail engineering team ships a flash-sale feature. Traffic spikes 10×. Their Azure CosmosDB bill triples within 24 hours. Queries that ran in 5ms now take 800ms. The on-call engineer bumps provisioned R...
Azure Cosmos DB API Modes Explained: NoSQL, MongoDB, Cassandra, PostgreSQL, Gremlin, and Table
TLDR: Cosmos DB's six API modes are wire-protocol compatibility layers over one shared ARS storage engine — except PostgreSQL (Citus), which is genuinely different. Every API emulates its native database incompletely, and those gaps are structural, n...
Sub-topic
2 articles
Partitioning Approaches in SQL and NoSQL: Horizontal, Vertical, Range, Hash, and List Partitioning
TLDR: Partitioning splits one logical table into smaller physical pieces called partitions. The database planner skips irrelevant partitions entirely — turning a 30-second full-table scan into a 200ms single-partition read. Range partitioning is best...
Sharding Approaches in SQL and NoSQL: Range, Hash, and Directory-Based Strategies Compared
TLDR: Sharding splits your database across multiple physical nodes so no single machine carries all the data or absorbs all the writes. The strategy you choose — range, hash, consistent hashing, or directory — determines whether range queries stay ch...
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
Database Anomalies: How SQL and NoSQL Handle Dirty Reads, Phantom Reads, and Write Skew
TLDR: Database anomalies are the predictable side-effects of concurrent transactions — dirty reads, phantom reads, write skew, and lost updates. SQL databases use MVCC and isolation levels to prevent them; PostgreSQL's Serializable Snapshot Isolation...
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...
Sub-topic
1 article
BASE Theorem Explained: How it Stands Against ACID
TLDR TLDR: ACID (Atomicity, Consistency, Isolation, Durability) is the gold standard for banking. BASE (Basically Available, Soft state, Eventual consistency) is the standard for social media. BASE intentionally sacrifices instant accuracy in exchan...