Top 3 Backup and restore Interview Questions

Browse 3 real-world technical and behavioral interview questions about Backup and restore. Review scenarios, edge cases, and architectural best practices.

A maintenance script deletes rows it should not have touched, and nobody notices for six hours. Walk me through the recovery.

Replication propagates the deletion, so recovery depends on point-in-time restore from a base backup plus the write-ahead log, and the hard part is not the restore but extracting one tenant's rows from a shared store while the rest of the system keeps serving traffic.

hardscenario

You have just joined and you are asked whether the company could restore production if the primary database were destroyed right now. How do you find out?

You cannot answer it from configuration, only by performing a restore into an isolated environment and timing it. Establish the recovery targets first, then test each mechanism separately, because backup jobs that report success and replicas that are not backups are the two ways this claim is usually wrong.

hardscenario

You need to migrate the schema of a 400-million-row table on a live system. Talk me through the plan, the backup you would want first, and how the connection pool affects it.

Every step is chosen to hold weak locks briefly - add the constraint invalid and validate separately, index concurrently, backfill in committed batches - behind a restore you have rehearsed and timed, and a pool small enough that one blocked DDL statement does not exhaust it.

hardscenario