Core DBA Duties Under Supervision

Core DBA Duties Under Supervision

Your externship placement is where classroom knowledge becomes professional practice. During this phase you will perform real recurring database administration tasks alongside experienced DBAs, logging every action you take and receiving daily feedback from your assigned mentor. This lesson explains what those core duties look like in the field, how to execute them safely and accurately, and how to document your work so it satisfies both employer expectations and your program competency requirements.

Scheduled Backup Verification

Backup verification is not optional—it is the single most important recurring task a DBA performs. A backup that has never been tested is not a backup; it is an assumption. Each morning you should check the backup job's completion status in the scheduler or monitoring dashboard (examples: pgBackRest status in PostgreSQL environments, RMAN log review in Oracle environments, or automated backup reports in Azure SQL / SQL Server). Confirm that the job completed without errors, that the backup file or snapshot exists in the expected location, and that the file size is consistent with prior successful backups. Record the job name, completion timestamp, status, and any warnings in your field log. If a backup has failed or shows anomalies, escalate immediately to your mentor rather than attempting an unguided fix.

User and Role Provisioning

Access control is a security-critical function. When a ticket requests that a new user account be created or that an existing user's permissions be changed or revoked, you must follow the employer's documented runbook exactly. Principle of least privilege is the governing rule: grant only the permissions the role requires, nothing more. In PostgreSQL you will use statements such as `CREATE ROLE`, `GRANT`, and `REVOKE`. In SQL Server the equivalent objects are logins, users, and roles managed through T-SQL or the portal. In Oracle you will work with `CREATE USER`, `GRANT`, and role assignments. Always record the ticket number, the exact commands or GUI steps used, the before-and-after permission state, and confirmation that the change was tested and closed in the ticketing system.

Index Maintenance and Routine Maintenance Tasks

Over time, database tables accumulate dead rows (in PostgreSQL, called dead tuples) and indexes become bloated or fragmented, degrading query performance. In PostgreSQL, `VACUUM` reclaims storage from dead tuples and `ANALYZE` updates the query planner's statistics; `VACUUM ANALYZE` runs both in one pass. Oracle uses segment shrink and statistics gathering jobs. SQL Server uses index rebuild or reorganize operations. Before running any maintenance command on a production table, confirm with your mentor that the timing is acceptable (maintenance should generally occur during low-traffic windows) and that you understand the locking behavior of the command you are using. Log the table or index name, the command, the duration, and any output messages.

Performance Monitoring and Slow-Query Review

Database performance monitoring involves reviewing metrics such as query execution time, lock wait events, cache hit ratios, and I/O throughput. Most sites expose these through a monitoring tool (examples: pgBadger or pg_stat_statements for PostgreSQL, Enterprise Manager for Oracle, Query Store for SQL Server). Your job during the externship is to review slow-query logs on a scheduled basis, identify statements that exceed the site's defined threshold, and flag them for a senior DBA's review. Do not alter indexes or query plans without explicit mentor authorization. Document each flagged query: the statement text or a hash identifier, the observed execution time, the table(s) involved, and your preliminary hypothesis about the cause.

Participating in Team Meetings

Professional DBAs work within structured teams. Sprint standups, change-control boards, and data governance committees are all contexts where database decisions are made and communicated. When you attend these meetings, listen for decisions that relate to exam domains you are studying: data quality and governance (DAMA CDMP), cloud database management and security (DP-300), and database architecture and administration practices (Oracle DBA CA). Write a clear, concise paragraph in your field log after each meeting summarizing what was decided and why it matters to the database environment.

Responding to Trouble Tickets

Mentor-assigned trouble tickets give you controlled exposure to incident response. Common low-risk incidents include a failed scheduled job, a locked user account, and a disk-space alert on a data volume. Follow this sequence for every ticket: (1) read the alert or ticket description carefully; (2) reproduce or verify the symptom before making any change; (3) consult the employer runbook or SOP for the relevant procedure; (4) apply the fix using only the access and steps authorized for your role; (5) verify that the issue is resolved; (6) document every step and have your mentor review and sign off the entry in your field log. Never attempt a fix that falls outside your authorized scope—escalate instead.

Safety and Professional Conduct in the Database Environment

Database administration carries operational safety responsibilities that parallel physical-trade safety rules. Data loss or unauthorized disclosure can cause serious financial and legal harm. Key safety practices include: never executing a destructive command (`DROP`, `DELETE` without `WHERE`, `TRUNCATE`) on a production object without written authorization and a confirmed backup; always working in a change-control window when the employer requires one; protecting credentials—never share passwords or store them in plain text; and reporting any suspected security incident (unusual login, unexpected privilege escalation, data anomaly) to your mentor immediately. Treat all employer data as confidential; do not copy production data to personal devices or accounts.

Logging Requirements

Your field log is both a learning record and a professional artifact. Each entry must include the date, start and end time, task name, specific commands or actions taken, the system or database name (use the employer's shorthand if required for confidentiality), the outcome, and any issues escalated. Minimum requirement for this placement phase is 108 dated, task-level hours. Gaps or vague entries will not count toward the hour total during mentor review.