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PROFESSIONAL-DATA-ENGINEER · Question #367

You have 100 GB of data stored in a BigQuery table. This data is outdated and will only be accessed one or two times a year for analytics with SQL. For backup purposes, you want to store this data…

The correct answer is D. 1. Perform a BigQuery export to a Cloud Storage bucket with archive storage class. Exporting to Cloud Storage with the archive storage class is the lowest-cost option for data accessed only once or twice a year - archive class is designed exactly for long-lived, rarely-read data. Option D likely includes the critical second step of setting a Cloud Storage…

Submitted by andres_qro· Mar 30, 2026Designing data processing systems

Question

You have 100 GB of data stored in a BigQuery table. This data is outdated and will only be accessed one or two times a year for analytics with SQL. For backup purposes, you want to store this data to be immutable for 3 years. You want to minimize storage costs. What should you do?

Options

  • A
    1. Create a BigQuery table clone.
  • B
    1. Create a BigQuery table snapshot.
  • C
    1. Perform a BigQuery export to a Cloud Storage bucket with archive storage class.
  • D
    1. Perform a BigQuery export to a Cloud Storage bucket with archive storage class.

How the community answered

(53 responses)
  • A
    8% (4)
  • B
    15% (8)
  • C
    4% (2)
  • D
    74% (39)

Explanation

Exporting to Cloud Storage with the archive storage class is the lowest-cost option for data accessed only once or twice a year - archive class is designed exactly for long-lived, rarely-read data. Option D likely includes the critical second step of setting a Cloud Storage retention policy (bucket lock) for 3 years, which enforces immutability by preventing deletion or modification until the retention period expires, satisfying the backup requirement.

Why the distractors are wrong:

  • A (table clone): A BigQuery clone is a lightweight copy inside BigQuery, billed at BigQuery storage rates - far more expensive than Cloud Storage archive class for infrequently accessed data, and clones don't enforce immutability.
  • B (table snapshot): Snapshots are point-in-time references tied to the original table and also billed as BigQuery storage; they're useful for recovery, not cost-minimized, immutable, long-term archival.
  • C: Though C appears identical in text, it likely omits the retention lock step, meaning the data could still be deleted or overwritten - failing the immutability requirement.

Memory tip: Think of the requirement in two parts - cheap + cold points to archive storage class, and immutable always means you need a retention policy/lock. If a question demands both, the answer must include both steps.

Topics

#BigQuery export#Cloud Storage Archive#Data lifecycle management#Cost optimization

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