DEA-C01 Data Operations and Support Practice Question
A data engineer is monitoring an Amazon Redshift cluster and notices that the disk space usage is increasing rapidly. The engineer wants to reclaim space from deleted rows. Which command should the engineer run?
⚠ Common exam trap
DEA-C01 often tests the distinction between VACUUM (space reclamation and re-sort) and ANALYZE (statistics refresh) — candidates who conflate maintenance commands pick ANALYZE, which does nothing for deleted-row disk usage.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
VACUUM
VACUUM in Amazon Redshift reclaims disk space occupied by rows marked for deletion and re-sorts rows to restore sort order. When rows are deleted, they are only logically marked until VACUUM runs, so disk usage keeps growing. Running VACUUM (or VACUUM DELETE ONLY) releases that space back to the system.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
VACUUM
Why this is correct
VACUUM reclaims storage occupied by deleted rows and re-sorts unsorted data in Amazon Redshift, directly addressing rapidly growing disk usage. It is the specific maintenance command that returns freed blocks to the system for reuse.
- ✗
ANALYZE
Why it's wrong here
ANALYZE only refreshes table statistics for the query planner; it deletes nothing and reclaims no storage. VACUUM performs the block merge that frees space occupied by deleted rows. ANALYZE is the right choice when query plans degrade from stale statistics, not when disk usage climbs.
- ✗
UNLOAD
Why it's wrong here
UNLOAD exports query results to Amazon S3; it removes no rows from Redshift tables. VACUUM reclaims space from deleted rows by re-sorting and merging blocks. UNLOAD suits data extraction and migration scenarios, which is why it appears plausible here despite leaving disk usage unchanged.
- ✗
COPY
Why it's wrong here
COPY loads data into Redshift tables from Amazon S3, DynamoDB or remote hosts, so it increases stored rows rather than reclaiming space. VACUUM reclaims storage from deleted rows. COPY is correct when ingesting new datasets, which is why it looks plausible in a storage-management question.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Amazon Web Services exam blueprint
This DEA-C01 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the DEA-C01 exam.