PostgreSQL Engineer Video Interview Questions

Introduction

Hiring the right PostgreSQL Engineer is critical for Information Technology teams that depend on reliable, performant, and scalable data platforms. A strong engineer helps ensure data integrity, efficient queries, and robust disaster recovery procedures.

This guide provides role-focused interview questions for screening PostgreSQL Engineer candidates. It covers basic, intermediate, and advanced technical questions and includes five pre-screening one-way video interview questions ideal for use on ScreeningHive.

PostgreSQL Engineer Interview Questions

Basic PostgreSQL Engineer Interview Questions

• What is PostgreSQL and what are its key features compared to other relational databases?
• Explain ACID properties and how PostgreSQL ensures them.
• What is MVCC and how does it affect concurrent transactions in PostgreSQL?
• Describe the difference between a primary key and a unique constraint.
• When would you use an index and what are common index types in PostgreSQL?
• What is VACUUM, and why is autovacuum important?
• Explain the difference between JSON and JSONB in PostgreSQL and when to use each.
• How do you back up a PostgreSQL database at a basic level?

Intermediate PostgreSQL Engineer Interview Questions

• You have a slow SELECT query. How do you diagnose and improve its performance using EXPLAIN ANALYZE?
• Describe a strategy to design and implement table partitioning for a large time-series table.
• How do you choose appropriate values for shared_buffers and work_mem on a production server?
• Explain how streaming replication works and how you would set up a standby server.
• How do you detect and resolve table bloat caused by long-running transactions?
• Walk through how you would perform a major schema migration with minimal downtime.
• What are replication slots and how do they relate to logical replication and WAL retention?
• Describe how you would implement connection pooling for a high-traffic application.
• How do you tune autovacuum settings for a database with high write volume?
• Explain common causes of checkpoint spikes and approaches to mitigate them.

Advanced PostgreSQL Engineer Interview Questions

• Discuss strategies for scaling PostgreSQL horizontally. When would you choose sharding over read replicas?
• Explain point-in-time recovery. How do you implement PITR and test it?
• Describe the internals of the PostgreSQL query planner and how planner statistics influence execution plans.
• How do you design a cross-region replication or multi-datacenter architecture while minimizing data lag?
• What techniques do you use to reduce lock contention in heavy OLTP workloads?
• Discuss tuning WAL settings and checkpoint behavior for write-heavy systems.
• Explain logical decoding and use cases for change data capture with PostgreSQL.
• Describe how you would approach capacity planning for database growth over the next three years.
• How do you evaluate and manage third-party extensions or custom modules in a production environment?
• Share an approach to lead a database reliability incident: triage, mitigation, root cause analysis, and follow-up.

Pre-Screening Video Interview Questions for PostgreSQL Engineer

These prompts are ideal for one-way video interviews on ScreeningHive. They help hiring teams assess communication, practical experience, and problem solving before live interviews.

1. Describe your most significant PostgreSQL project and your responsibilities.

   This question evaluates practical experience, ownership, and the candidate's ability to summarize technical contributions and outcomes.

2. Walk through how you would investigate a sudden performance regression on a critical production query.

   This assesses diagnostic approach, familiarity with tools like EXPLAIN ANALYZE and pg_stat_activity, and prioritization under pressure.

3. Explain MVCC and how VACUUM and autovacuum interact with it.

   This checks conceptual understanding of concurrency, transaction isolation, and routine maintenance tasks.

4. Describe a migration or major upgrade you planned and executed, and how you minimized downtime and risk.

   This evaluates planning skills, risk mitigation, testing strategy, and communication during change management.

5. How do you ensure database security and compliance in your deployments?

   This question measures knowledge of access control, encryption, auditing, and operational practices for maintaining compliance.

Conclusion

Using targeted questions for basic, intermediate, and advanced topics helps hiring managers and recruiters identify the best PostgreSQL Engineer candidates. The pre-screening one-way video questions accelerate shortlisting and provide consistent insight into candidate skills and communication.

ScreeningHive one-way video interviews enable faster screening, standardized evaluations, and better hiring decisions for IT teams. Incorporate these prompts into your screening workflow to save time and improve candidate quality.