PDE Ingesting and Processing the Data Practice Question
A data engineer needs to ingest on-premises Oracle CDC data into BigQuery in near real-time with minimal operational overhead. Which service should they use?
⚠ Common exam trap
Google often tests the distinction between batch migration tools (Storage Transfer Service, Transfer Appliance) and streaming CDC services (Datastream), leading candidates to choose a batch option when the question explicitly requires near-real-time ingestion.
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
✓
Datastream
Datastream is purpose-built for streaming change data capture (CDC) from Oracle and other sources into BigQuery with near-real-time latency and minimal operational overhead. It handles schema propagation, checkpointing, and automatic retries, eliminating the need to manage custom ingestion pipelines.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Pub/Sub + Dataflow
Why it's wrong here
Pub/Sub plus Dataflow requires you to build and operate the CDC pipeline yourself, adding operational overhead the stem explicitly rules out. It is tempting because Dataflow handles custom streaming transformations well, and would be correct if no managed Oracle CDC connector existed.
- ✗
Storage Transfer Service
Why it's wrong here
Storage Transfer Service moves files and objects between object stores on a scheduled batch basis; it cannot read Oracle redo logs or apply row-level changes, so near-real-time CDC is impossible. It is tempting because it excels at bulk migrations from S3-compatible or on-premises file systems into Cloud Storage.
- ✗
Transfer Appliance
Why it's wrong here
Transfer Appliance is a physical rack-mounted device shipped to your site for bulk offline data copying, so it cannot deliver near-real-time change records. It is tempting for migrating very large datasets where network bandwidth makes online transfer impractical, but Oracle CDC requires continuous streaming.
- ✓
Datastream
Why this is correct
Datastream provides serverless change data capture from Oracle into BigQuery with minimal operational overhead, replicating changes in near real-time. It satisfies both constraints directly, unlike batch extraction tools or custom pipelines that require managing infrastructure.
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This PDE practice question is part of Courseiva's free Google Cloud 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 PDE exam.