Data Systems
NewSQL and Distributed SQL
NewSQL databases combine the best of SQL and NoSQL: strong consistency, ACID transactions, and horizontal scalability. Master the architecture of Spanner, CockroachDB, and YugabyteDB.
- Consistency â Serializable transactions across distributed nodes
- Scalability â Horizontal scaling with automatic sharding
- Global â Multi-region deployment with low-latency reads
NewSQL proves you don't have to sacrifice consistency for scalability.
The NewSQL Promise
NewSQL databases aim to provide the scalability of NoSQL with the ACID guarantees and SQL interface of traditional relational databases.
The CAP Theorem in Practice
Google Spanner
TrueTime and External Consistency
Spanner Architecture
| Component | Purpose |
|---|---|
| Spanserver | Stores data, serves queries |
| Zone Master | Assigns data to spanservers |
| Directory Manager | Moves data between zones |
| Placement Driver | Manages cross-zone replication |
CockroachDB
Raft Consensus
CockroachDB vs Spanner
| Feature | CockroachDB | Spanner |
|---|---|---|
| Consensus | Raft | Paxos |
| Time Source | Hybrid logical clocks | TrueTime (atomic clocks) |
| Deployment | Self-hosted, cloud | GCP only |
| Consistency | Serializable | External consistency |
| Latency | Higher (no atomic clocks) | Lower (TrueTime) |
| Cost | Lower | Higher (GCP pricing) |
Distributed SQL Internals
Automatic Sharding
Transaction Coordination
When to Use NewSQL
| Use Case | Justification |
|---|---|
| Global financial systems | Strong consistency across regions |
| Multi-region applications | Low-latency reads worldwide |
| ACID at scale | Transactions across sharded data |
| Regulatory compliance | Data residency with consistency |
| Migration from monolith | Keep SQL while gaining scalability |
Practice Exercises
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Architecture Comparison: Compare Spanner and CockroachDB for a global e-commerce platform. What are the trade-offs in terms of consistency, latency, cost, and operational complexity?
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Transaction Design: Design a distributed transaction for a banking system that transfers money between accounts in different regions. How do you handle the coordination?
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Sharding Strategy: If you were designing CockroachDB's automatic sharding, what algorithm would you use to distribute data? How do you handle hot spots?
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Migration Planning: Your team is migrating from PostgreSQL to CockroachDB. What are the main challenges, and how would you approach the migration?
What to Learn Next
-> Spanner and CockroachDB Deep dive into specific NewSQL implementations.
-> SQL Deep Dive PostgreSQL, MySQL, indexing strategies, and query optimization.
-> Distributed Consensus Paxos, Raft, and consensus protocols.
-> CAP Theorem Consistency models, availability, and partition tolerance.
-> Data Partitioning Sharding strategies, consistent hashing, and partition keys.
-> Data Replication Sync vs async replication, leader election, and consistency.