5 exercises — practise answering Database Reliability Engineer interview questions in professional technical English.
0 / 10 completed
1 / 10
The interviewer asks: "How do you define and measure SLOs for a PostgreSQL cluster that serves a transactional application?" Which answer best demonstrates Database Reliability Engineer expertise?
Option B is strongest because it defines multi-dimensional SLOs with specific numeric targets, explains the measurement mechanism for each (synthetic heartbeat, pg_stat_statements, replication LSN), calculates the error budget, and describes proactive alerting at burn rate. Option A defines only availability without latency or replication dimensions. Option C is reactive with no quantified targets. Option D incorrectly separates database reliability from SLO ownership.
2 / 10
The interviewer asks: "Walk me through a failover procedure when the primary PostgreSQL instance becomes unresponsive." Which answer best demonstrates Database Reliability Engineer expertise?
Option B is strongest because it describes an automated four-phase procedure with specific tooling (Patroni, etcd, STONITH, PgBouncer), explains why each phase is necessary (especially fencing for split-brain prevention), and gives concrete timing targets. Option A is unsafe — restarting a primary during a failure scenario can cause data loss if it has already been superseded. Option C is manual and too slow for a production SLO. Option D defers reliability to the provider without understanding the failover mechanism.
3 / 10
The interviewer asks: "How do you detect and resolve connection pool exhaustion in a production PostgreSQL environment?" Which answer best demonstrates Database Reliability Engineer expertise?
Option B is strongest because it distinguishes the two root causes, provides specific SQL diagnostic queries, explains immediate and long-term remediation for each cause, and introduces the pool mode improvement (session vs transaction) that gives a 10x capacity improvement. Option A increases max_connections without understanding the cause — this can destabilise PostgreSQL memory and worsen performance. Option C adds read replicas, which does not help with write connection saturation. Option D restarts are a blunt instrument that causes downtime and does not address the underlying cause.
4 / 10
The interviewer asks: "How do you perform Point-In-Time Recovery (PITR) and what are the key RTO/RPO trade-offs?" Which answer best demonstrates Database Reliability Engineer expertise?
Option B is strongest because it explains the WAL archiving mechanism, names specific tooling (pgBackRest, WAL-G), gives concrete RPO and RTO figures with their determinants, describes the recovery_target_time configuration, and emphasises regular restore testing. Option A describes log shipping from application logs, not PostgreSQL WAL — this cannot guarantee consistency. Option C snapshots provide coarser-grained recovery than WAL and the RPO equals the snapshot interval. Option D describes HA failover, not PITR — replication cannot recover from logical data corruption or accidental deletion.
5 / 10
The interviewer asks: "How do you investigate and remediate a slow query that is causing latency spikes during peak traffic?" Which answer best demonstrates Database Reliability Engineer expertise?
Option B is strongest because it follows a structured five-step methodology: identifying high-impact queries by total time, capturing execution plans with ANALYZE and BUFFERS, diagnosing specific root causes (statistics staleness, bad plans), testing on a clone, and monitoring post-fix regressions. Option A adds indexes blindly, which can worsen write performance and may not address the actual problem. Option C runs EXPLAIN on a single instance without checking statistics, which is incomplete. Option D caches results, which is a valid performance pattern but does not fix the query itself and introduces cache invalidation complexity.
6 / 10
Reviewer: 'This query is running incredibly slowly. It's impacting user experience significantly. Can you investigate the execution plan and consider adding an index?'
Which of the following responses best demonstrates a Database Reliability Engineer's approach to this situation?
The correct answer focuses on a methodical approach – analyzing the execution plan is *crucial* in identifying performance bottlenecks. Simply scaling up resources might mask the underlying problem without addressing the root cause, and monitoring logs doesn't directly solve slow queries. This demonstrates understanding of query optimization techniques.
7 / 10
Sarah (DevOps): 'The replication lag between our primary and replica database is spiking again! It's currently at 30 minutes. We need to understand why.'
Which of the following Slack responses would be most appropriate for a Database Reliability Engineer?
A Database Reliability Engineer's response needs to be proactive and focused on diagnosis. Simply monitoring isn't sufficient – a systematic investigation into potential causes (log analysis, network checks) is essential. The other options represent either passive acceptance or misdirected solutions.
8 / 10
You're writing the PR description for a change that introduces automated backups of our production PostgreSQL database. The description should be clear and concise.
Which of the following descriptions best conveys your role as a Database Reliability Engineer?
The best answer highlights not just *what* was done (backups), but also *why* and *how* it contributes to reliability – including monitoring and key policies. It demonstrates an understanding of backup strategy and its importance for disaster recovery.
9 / 10
During a daily stand-up meeting, you're asked: 'What did you work on yesterday?'
You respond: 'I spent the day investigating an issue with slow query performance in our user reporting service.'
Which of the following would be the MOST effective follow-up statement to further demonstrate your expertise as a Database Reliability Engineer?
The best response provides a concrete action and insight – showing you actively investigated and proposed a solution. It's more than just stating you had a problem; it demonstrates your troubleshooting skills and proactive approach to resolving issues. The other options are less relevant to the role.
10 / 10
You're receiving an API response from a monitoring tool showing high CPU utilization on your PostgreSQL database server. The response includes the following data:
`{"metric": "CPU Utilization", "value": "95%", "timestamp": "2024-10-27T10:00:00Z", "server": "db-prod-01"}`
Which of the following actions would be MOST appropriate for a Database Reliability Engineer to take based on this API response?
The correct answer outlines a systematic investigation process – crucial for diagnosing performance issues. It's not enough to simply acknowledge the high CPU value; you need to determine *why* it's elevated and what actions can be taken to address it. The other options represent reactive or incorrect responses.
What does "Database Reliability Engineer — IT English Interview Practice" cover?
Practise answering Database Reliability Engineer interview questions in professional technical English. Covers database SLOs, failover procedures, connection pool exhaustion, PITR, and slow query remediation.
How many questions are in this interview set?
This set has 10 exercises, each with a full explanation.
Is this exercise free to use?
Yes. Every exercise on CoderSlingo, including this one, is free to use with no account, sign-up, or paywall.
Do these exercises include model answers?
Yes. Each interview question gives you several possible responses and asks you to pick the one that communicates most clearly and completely — the explanation then breaks down exactly why that answer works, including the specific vocabulary a strong candidate would use.
What if I choose an answer that isn't the strongest one?
You'll see which option was correct and read a full explanation of why it's stronger than the alternatives, plus the key vocabulary and phrasing worth reusing in a real interview.
Can I retry the questions?
Yes — use the "Try again" button on the results screen to reset and go through the set again.
Is this the same as a real technical or behavioural interview?
No — it's focused practice for the language side of interviewing: recognising which phrasing sounds precise and confident versus vague, and knowing the vocabulary interviewers expect for this role. It won't replace mock interviews, but it builds the vocabulary you'll need in one.
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Who writes these interview questions?
Every question is written by the CoderSlingo team based on real technical interview patterns for this role, then reviewed for accuracy and clarity.