Storage use increased after adding columns to a Redshift table.
Inspect value distributions and choose suitable column encodings.
Which approach is most appropriate?
Use ANALYZE COMPRESSION and data distribution to select column-level ENCODE settings, then measure CPU and I/O.
Detailed explanation
Disabling compression can increase storage and I/O.
Disabling compression can increase storage and I/O.
S3 lifecycle rules do not change internal Redshift column encoding.
S3 lifecycle rules do not change internal Redshift column encoding.
Different types and value distributions need different compression decisions.
Different types and value distributions need different compression decisions.
Compression candidates can be compared against column type and cardinality.
Compression candidates can be compared against column type and cardinality.
Check official documentation
Compare the following points with the official documentation.
Amazon Redshift column compression、ANALYZE COMPRESSION、ENCODEの公式説明を確認する。
What to confirm
圧縮方式を列のデータ分布に合わせて選ぶ理由を説明できる。
Key points
- ENCODE
- ANALYZE COMPRESSION
- Cardinality
- I/O
Notes
- Environment: AWS公式DEA-C01試験ガイドと各サービスの公式ドキュメントの確認
- Confirm current AWS service behavior in the official DEA-C01 documentation.
Foundation review
CPU versus I/O
Compression can reduce I/O while adding CPU work, so measure the workload.
Reassessment
New columns and changing distributions can require another compression analysis.