PDE Ingesting and Processing the Data Practice Question
A company wants to ingest data from an on-premises Oracle database into BigQuery in near real-time with minimal latency. The database has a high volume of inserts and updates. Which service should they use?
⚠ Common exam trap
PDE often tests the difference between batch transfer services and CDC services; candidates incorrectly choose BigQuery Data Transfer Service or Pub/Sub for real-time Oracle replication, not realizing Datastream is the managed CDC solution.
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 correct because it is a serverless change data capture (CDC) service that replicates data from Oracle to BigQuery in near real-time with minimal latency. It reads the Oracle redo logs (via LogMiner or binary log reader) to capture inserts, updates, and deletes and streams them to BigQuery.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Datastream
Why this is correct
Datastream provides serverless change data capture (CDC) by reading Oracle redo logs, streaming inserts and updates continuously into BigQuery with sub-minute latency. This directly satisfies the near real-time, high-volume insert-and-update constraint, unlike batch extraction tools that cannot capture ongoing changes.
- ✗
BigQuery Data Transfer Service
Why it's wrong here
BigQuery Data Transfer Service runs scheduled batch loads from supported sources such as Cloud Storage or SaaS applications; it cannot capture Oracle change data continuously. It is tempting because it is the native BigQuery ingestion service, and would be correct for periodic, non-real-time transfers.
- ✗
Pub/Sub
Why it's wrong here
Pub/Sub is a messaging transport, not a database change-capture mechanism; it cannot read Oracle redo logs or replicate inserts and updates by itself. It is tempting because it decouples streaming pipelines, and would be correct as the delivery layer once Datastream extracts the changes.
- ✗
Storage Transfer Service
Why it's wrong here
Storage Transfer Service moves files between object stores and file systems, not row-level changes from a relational database. It is tempting because it handles large-scale on-premises-to-cloud movement, and would be correct for migrating bulk files or objects rather than streaming database updates.
Quick reference
Cloud Service Model Comparison
| Model | You Manage | Provider Manages | Examples |
|---|---|---|---|
| IaaS | OS, runtime, apps, data | Hardware, hypervisor, networking | EC2, Azure VMs, GCP Compute Engine |
| PaaS | Apps and data | OS, runtime, middleware, hardware | Elastic Beanstalk, Azure App Service |
| SaaS | Data and settings only | Everything else | Microsoft 365, Salesforce, Workday |
| FaaS / Serverless | Function code only | Infra, scaling, runtime | Lambda, Azure Functions, Cloud Run |
| CaaS | Containers and apps | Kubernetes, OS, hardware | EKS, AKS, GKE |
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Google Cloud exam blueprint
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.