This is a production DBA post on open source engines: PostgreSQL and MySQL, standalone and clustered, across development, test and live. It is the unglamorous half of database work — the half where replication lag, lock contention and a badly planned query decide whether anyone else can do their job today.
It suits someone who tunes rather than guesses, who has restored from backup in earnest, and who writes the root cause analysis afterwards because the next incident depends on it.
What you would be doing
Install, configure, maintain and upgrade PostgreSQL 12+ and MySQL 8+, standalone and clustered.
Run routine maintenance properly — schema housekeeping, index maintenance, statistics, retention.
Manage users, roles, privileges and authentication on least-privilege lines.
Forecast storage growth and advise on partitioning and archiving before capacity becomes an incident.
Troubleshoot production problems: data corruption, replication failures, performance degradation.