Redshift queries slow down because tables are unsorted after many deletes. What helps?
Why D is the answer
VACUUM and ANALYZE
VACUUM reclaims space and re-sorts. ANALYZE updates statistics.
In detail
- VACUUM re-sorts and reclaims space.
- ANALYZE refreshes statistics.
- Each command has a different job.
Use case
An illustrative scenario, not a real incident.
After heavy deletes, queries slow down. VACUUM re-sorts the table, and ANALYZE refreshes planner statistics.
See it in different ways
mindmap
root((Distribution))
ALL
Small dimensions
KEY
Large joined tables
Care
VACUUM
ANALYZEflowchart TD
Q{"What is the issue?"}
Q -->|"Unsorted, deleted rows"| A0["VACUUM"]
Q -->|"Stale statistics"| A1["ANALYZE"]Key point: VACUUM re-sorts, and ANALYZE updates statistics.
Why the other options are wrong
- A. A new distribution style only
- Distribution does not re-sort rows.
- B. A larger S3 bucket
- S3 is unrelated here.
- C. More frequent snapshots
- Snapshots are backups.