Interview kitsBlog

Your dream job? Lets Git IT.
Interactive technical interview preparation platform designed for modern developers.

XGitHub

Platform

  • Categories

Resources

  • Blog
  • About the app
  • FAQ
  • Feedback

Legal

  • Privacy Policy
  • Terms of Service

© 2026 LetsGit.IT. All rights reserved.

LetsGit.IT/Categories/Microservices
Microserviceseasy

Why is sharing one database between microservices risky?

Tags
#shared-database#coupling#data-ownership
Back to categoryPractice quiz

Answer

It couples services through shared schema and transactions: one change can break others, deployments must be coordinated, and ownership becomes unclear. It also makes scaling and security boundaries harder.

Advanced answer

Deep dive

Expanding on the short answer — what usually matters in practice:

  • Context (tags): shared-database, coupling, data-ownership
  • Scaling: what scales horizontally vs vertically, where bottlenecks appear.
  • Reliability: retries/circuit breakers/idempotency, observability (logs/metrics/traces).
  • Evolution: keep changes cheap (boundaries, contracts, tests).
  • Explain the "why", not just the "what" (intuition + consequences).
  • Trade-offs: what you gain/lose (time, memory, complexity, risk).
  • Edge cases: empty inputs, large inputs, invalid inputs, concurrency.

Examples

A tiny example (an explanation template):

// Example: discuss trade-offs for "why-is-sharing-one-database-between-microservice"
function explain() {
  // Start from the core idea:
  // It couples services through shared schema and transactions: one change can break others, d
}

Common pitfalls

  • Too generic: no concrete trade-offs or examples.
  • Mixing average-case and worst-case (e.g., complexity).
  • Ignoring constraints: memory, concurrency, network/disk costs.

Interview follow-ups

  • When would you choose an alternative and why?
  • What production issues show up and how do you diagnose them?
  • How would you test edge cases?

Related questions

Monoliths
What is a “big ball of mud” and how can you recognize it?
#maintainability#coupling#code-smell
Monoliths
What is a “distributed monolith” and how do you avoid it?
#distributed-monolith#coupling#microservices
Monoliths
Database split during extraction — what is the hardest part?
#database#migration
#data-ownership
Architecture
Coupling vs cohesion — what do you want and why?
#coupling#cohesion#design