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Google PCA Practice Question: Analysing and Optimising Technical and Business Processes

A company uses Cloud CDN to serve static content from a Cloud Storage bucket. They update the content every 2 hours, but users sometimes see stale content for up to 24 hours. They need users to see the latest content within 5 minutes of an update. Which action should they take?

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

Set a short max-age TTL (e.g., 5 minutes) on the objects

To ensure content is served fresh, they should set a short max-age (cache TTL) on the object metadata or via the bucket's default object holding. Invalidating the cache is a reactive measure, but setting a short TTL ensures that cache entries expire quickly. Cache modes affect query string handling, not TTL. Cache keys affect how content is cached but not the freshness duration.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • Use cache invalidation after each update

    Why it's wrong here

    Cache invalidation removes objects from Cloud CDN edge caches, but the default minimum TTL for Cloud CDN is 5 minutes, and the company updates content every 2 hours; invalidation alone cannot force the CDN to fetch fresh content from the bucket within 5 minutes if the TTL is set longer than that. This option is tempting because invalidation is designed to purge stale cached objects immediately after a change, and it would be correct if the requirement were to clear outdated data from edges without adjusting cache settings.

  • Use custom cache keys

    Why it's wrong here

    Custom cache keys control cache grouping, not freshness.

  • Set a short max-age TTL (e.g., 5 minutes) on the objects

    Why this is correct

    Setting a short TTL tells CDN to cache for only 5 minutes, after which it re-fetches from origin. This ensures fresh content within 5 minutes.

  • Change cache mode to CACHE_ALL_STATIC

    Why it's wrong here

    Cache mode affects what gets cached (e.g., static vs dynamic), not the TTL.

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Written by Johnson Ajibi, MSc IT Security

Senior Network & Security Engineer · founder of Courseiva

This PCA 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 PCA exam.