PMLE Practice Question: Collaborating Within and Across Teams to Manage Data and Models
You need to create a reproducible snapshot of a BigQuery table as of a specific timestamp for ML model training. The snapshot should be queryable without copying the entire dataset. Which BigQuery feature should you use?
⚠ Common exam trap
The trap here is conflating time travel (a transient query window) with table snapshots (a durable, queryable object) — candidates often pick FOR SYSTEM_TIME AS OF because it sounds like a snapshot, but it does not persist beyond the time-travel window.
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
✓
BigQuery table snapshots
BigQuery table snapshots create a lightweight, queryable copy of a table at a point in time using copy-on-write storage — only changed data consumes additional bytes, and the snapshot is a first-class table you can query directly. This satisfies the requirement for a reproducible, timestamped, queryable snapshot without duplicating the full dataset. Time travel, by contrast, is a query-time window (default 7 days) and does not persist as a durable object.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
BigQuery export to Cloud Storage as Parquet
Why it's wrong here
Exporting to Cloud Storage produces Parquet files that are not queryable in place and copies the full dataset out of BigQuery, failing both requirements. It is tempting because exports give durable, versioned training artefacts, and would be right when feeding external frameworks or archiving data cheaply rather than querying a snapshot.
- ✗
BigQuery time travel (FOR SYSTEM_TIME AS OF)
Why it's wrong here
Time travel reads historical data only within the configured retention window, defaulting to seven days, so it cannot reproduce a snapshot from an older timestamp and the data expires. It is tempting because FOR SYSTEM_TIME AS OF queries past states without copying, which suits short-term rollback or recent point-in-time inspection.
- ✗
CREATE TABLE AS SELECT with WHERE clause
Why it's wrong here
CTAS with a WHERE clause filters on a column value, not on commit timestamps, so it cannot reconstruct the table's exact state at an arbitrary past instant, and it materialises a full copy. It is tempting because it produces a queryable, immutable training table, which suits point-in-time snapshots only when a reliable timestamp column exists.
- ✓
BigQuery table snapshots
Why this is correct
BigQuery table snapshots capture a table's contents at a specified timestamp as a lightweight, queryable reference that shares storage with the base table rather than duplicating data. This satisfies the stem's reproducibility and no-full-copy constraints.
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Same concept, more angles
1 more way this is tested on PMLE
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A data engineer wants to create a BigQuery table snapshot for point-in-time recovery of a critical dataset. The snapshot should be created daily and retained for 30 days. What should they use?
medium- A.BigQuery copy job
- B.BigQuery time travel
- ✓ C.BigQuery scheduled queries with CREATE SNAPSHOT
- D.BigQuery export to Cloud Storage
Why C: The correct answer is C: BigQuery scheduled queries with CREATE SNAPSHOT. BigQuery supports table snapshots via the CREATE SNAPSHOT statement, which creates a lightweight, read-only copy of a table at a specific point in time. By scheduling this statement daily using BigQuery's scheduled query feature, the engineer can automate daily snapshots. Snapshots are retained until explicitly deleted, so setting a retention policy of 30 days can be managed by scheduling deletion of snapshots older than 30 days or by using the expiration_timestamp option when creating the snapshot.
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 PMLE 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 PMLE exam.