Tutorials System Design Tutorial
Distributed Databases — Complete Guide
Distributed Databases — Complete Guide: free step-by-step lesson with examples, common mistakes, and interview tips — part of System Design Tutorial on Toolliyo Academy.
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System Design Tutorial · Lesson 28 of 100
Distributed Databases
Basics → Scale → Interview
Basics · 1 — Building blocks · ~6 min · Module 3: Database Systems
What is this?
Distributed databases spread storage and compute across nodes with built-in replication/sharding and their own consistency knobs.
Why should you care?
ShopNest global catalog or session store may need multi-region more than a single Postgres can give comfortably.
See it live — copy this example
Sketch the architecture on paper. These lessons focus on concepts and trade-offs.
Options vibe-check:
Cockroach/Spanner-like: SQL + distributed consensus
Cassandra-like: wide-column, AP-leaning
Dynamo-style: key-value, tunable consistency
ShopNest: keep money in regional SQL; global feed in distributed KVRun Example »
This lesson uses terminal or setup steps. Run commands on your computer — the live editor appears on coding lessons.
What happened?
- Distributed SQL aims for familiar transactions with higher latency.
- AP stores favor availability.
- Pick per workload, not one DB for everything.
Practice next
- Name one ShopNest dataset that needs multi-region.
- Name one that must stay in a single regional SQL.
- Write the consistency requirement for each.
- Place sessions in a multi-region cache/KV.
- Keep orders in regional primary SQL.
Remember
Distributed DB ≠ free unlimited scale. Consistency and latency trade. Split workloads by need.
Hybrid data plane
ShopNest uses SQL for orders, distributed KV for sessions.
Outcome: Each store plays to its strengths.
Interview prep for this lesson
Practice these questions aloud after reading—each links to a full structured answer.
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