PROFESSIONAL-DATA-ENGINEER · Question #346
You are running your BigQuery project in the on-demand billing model and are executing a change data capture (CDC) process that ingests data. The CDC process loads 1 GB of data every 10 minutes into a
The correct answer is B. Create a BigQuery reservation for the job.. Option B is correct because BigQuery allows you to assign a reservation directly to a specific job by specifying the reservation_id in the job's configuration. This lets you apply committed-slot capacity (predictable pricing) exclusively to the scan-intensive CDC merge job, while
Question
Options
- ACreate a BigQuery reservation for the dataset.
- BCreate a BigQuery reservation for the job.
- CCreate a BigQuery reservation for the service account running the job.
- DCreate a BigQuery reservation for the project.
How the community answered
(38 responses)- A3% (1)
- B76% (29)
- C8% (3)
- D13% (5)
Explanation
Option B is correct because BigQuery allows you to assign a reservation directly to a specific job by specifying the reservation_id in the job's configuration. This lets you apply committed-slot capacity (predictable pricing) exclusively to the scan-intensive CDC merge job, while the rest of your project continues running on on-demand billing - giving you surgical cost control exactly where you need it.
Why the distractors are wrong:
- A (dataset): Datasets are not a valid reservation assignment target in BigQuery. Reservations attach to compute resources, not storage constructs.
- C (service account): BigQuery does not route reservation assignments by service account identity; this concept doesn't exist in the reservation model.
- D (project): While project-level reservation assignment is valid, it applies committed slots to all jobs in the project - not just the CDC process - which over-provisions and defeats the goal of targeted cost control.
Memory tip: Think of BigQuery reservation assignments as a targeting hierarchy: Org → Folder → Project → Job. Each level is more specific than the last. When you need to isolate cost for a single workload (like one CDC pipeline), go to the most specific valid target - the job - rather than blanketing the whole project.
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