The answer is to create a custom cache policy that includes only the v query string and excludes cookies. This improves the CloudFront cache hit ratio because forwarding all query strings and cookies to the origin forces CloudFront to treat each unique combination as a separate cached object, fragmenting the cache and reducing hits. By isolating only the versioning parameter (v) and stripping cookies, you ensure that all users receive the same static file from a single cached copy, regardless of other irrelevant query parameters or cookie values. On the SAA-C03 exam, this scenario tests your understanding of how CloudFront cache policies control cache keys and the impact of origin request policies on performance. A common trap is assuming you must forward all query strings or cookies to maintain functionality, but for static assets, only versioning parameters matter. Remember the mnemonic: “Version only, cookies gone” to maximize cache hits.
SAA-C03 Design High-Performing Architectures Practice Question
This SAA-C03 practice question tests your understanding of design high-performing architectures. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. A key principle to apply: cloudFront cache key determines if a request can be served from cache.. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Exhibit
CloudFront behavior summary for path pattern /static/*:
- Allowed methods: GET, HEAD
- Cache policy: forwards all query strings
- Origin request policy: forwards all cookies and the Authorization header
- Average cache hit ratio: 11%
Sample request log lines:
GET /static/app.js?v=18&userId=123 Cookie: session=abcd
GET /static/app.js?v=18&userId=987 Cookie: session=xyzt
GET /static/logo.svg?v=18&locale=en Cookie: session=mnop
Origin responses:
- All objects are identical for every viewer
- Objects are versioned only by the v query parameter
Based on the exhibit, which change will most improve the CloudFront cache hit ratio for the static assets while still serving the same files to all users?
CloudFront behavior summary for path pattern /static/*:
- Allowed methods: GET, HEAD
- Cache policy: forwards all query strings
- Origin request policy: forwards all cookies and the Authorization header
- Average cache hit ratio: 11%
Sample request log lines:
GET /static/app.js?v=18&userId=123 Cookie: session=abcd
GET /static/app.js?v=18&userId=987 Cookie: session=xyzt
GET /static/logo.svg?v=18&locale=en Cookie: session=mnop
Origin responses:
- All objects are identical for every viewer
- Objects are versioned only by the v query parameter
A
Create a custom cache policy that includes only the v query string and excludes cookies.
This removes unnecessary cache-key fragmentation. Since all users receive identical static files, forwarding user-specific cookies and irrelevant query strings destroys cache reuse. Keeping only the version parameter preserves correct object variation while allowing many more requests to hit the same cached object at the edge.
B
Enable Origin Shield and keep the current cache behavior unchanged.
Why wrong: Origin Shield can reduce origin load after a miss, but it does not fix a cache key that is fragmented by unnecessary request data.
C
Move the static assets to individual presigned URLs for each viewer.
Why wrong: Presigned URLs are for controlled access, not for improving cache efficiency when the content itself is identical for everyone.
D
Increase the CloudFront default TTL to 24 hours while continuing to forward all cookies and query strings.
Why wrong: A longer TTL helps only after a cacheable object is identified; forwarding user-specific data still creates too many distinct cache entries.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Create a custom cache policy that includes only the v query string and excludes cookies.
The CloudFront cache hit ratio for static assets is reduced when query strings and cookies are forwarded to the origin, because each unique combination creates a separate cache entry. By creating a custom cache policy that includes only the 'v' query string (used for versioning) and excludes cookies, CloudFront can cache a single object for all users regardless of other query parameters or cookie values, maximizing cache hits while still serving the same file.
Key principle: CloudFront cache key determines if a request can be served from cache.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
Create a custom cache policy that includes only the v query string and excludes cookies.
Why this is correct
This removes unnecessary cache-key fragmentation. Since all users receive identical static files, forwarding user-specific cookies and irrelevant query strings destroys cache reuse. Keeping only the version parameter preserves correct object variation while allowing many more requests to hit the same cached object at the edge.
Related concept
CloudFront cache key determines if a request can be served from cache.
✗
Enable Origin Shield and keep the current cache behavior unchanged.
Why it's wrong here
Origin Shield can reduce origin load after a miss, but it does not fix a cache key that is fragmented by unnecessary request data.
✗
Move the static assets to individual presigned URLs for each viewer.
Why it's wrong here
Presigned URLs are for controlled access, not for improving cache efficiency when the content itself is identical for everyone.
✗
Increase the CloudFront default TTL to 24 hours while continuing to forward all cookies and query strings.
Why it's wrong here
A longer TTL helps only after a cacheable object is identified; forwarding user-specific data still creates too many distinct cache entries.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates assume increasing TTL or enabling Origin Shield will fix a low cache hit ratio, when the real issue is an overly broad cache key caused by forwarding all query strings and cookies.
Detailed technical explanation
How to think about this question
CloudFront cache keys are derived from the request's origin, protocol, host, query string, cookies, and headers based on the cache policy. By default, forwarding all query strings and cookies creates a unique cache key for every permutation, which is especially harmful for static assets where only a versioning parameter (e.g., '?v=1') matters. A custom cache policy that includes only the 'v' query string and excludes cookies ensures that all users requesting the same versioned asset share a single cached object, dramatically improving the cache hit ratio without altering the delivered content.
KKey Concepts to Remember
CloudFront cache key determines if a request can be served from cache.
Custom cache policies allow granular control over cache key components.
Excluding cookies and irrelevant query strings prevents cache fragmentation.
A higher cache hit ratio reduces origin load and improves performance.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
CloudFront cache key determines if a request can be served from cache.
Real-world example
How this comes up in practice
A media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
What to study next
Got this wrong? Here's your next step.
Review cloudFront cache key determines if a request can be served from cache., then practise related SAA-C03 questions on the same topic to reinforce the concept.
Design High-Performing Architectures — This question tests Design High-Performing Architectures — CloudFront cache key determines if a request can be served from cache..
What is the correct answer to this question?
The correct answer is: Create a custom cache policy that includes only the v query string and excludes cookies. — The CloudFront cache hit ratio for static assets is reduced when query strings and cookies are forwarded to the origin, because each unique combination creates a separate cache entry. By creating a custom cache policy that includes only the 'v' query string (used for versioning) and excludes cookies, CloudFront can cache a single object for all users regardless of other query parameters or cookie values, maximizing cache hits while still serving the same file.
What should I do if I get this SAA-C03 question wrong?
Review cloudFront cache key determines if a request can be served from cache., then practise related SAA-C03 questions on the same topic to reinforce the concept.
What is the key concept behind this question?
CloudFront cache key determines if a request can be served from cache.
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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. Based on the exhibit, which change will most improve the CloudFront cache hit ratio for the static assets while still serving the same files to all users?
hard
✓ A.Create a custom cache policy that includes only the v query string and excludes cookies.
B.Enable Origin Shield and keep the current cache behavior unchanged.
C.Move the static assets to individual presigned URLs for each viewer.
D.Increase the CloudFront default TTL to 24 hours while continuing to forward all cookies and query strings.
Why A: Option A is correct because static assets (e.g., images, CSS, JS) are typically served identically to all users, so forwarding a unique query string like 'v' for versioning still allows CloudFront to cache a single object per version. By excluding cookies and other query strings, you prevent cache fragmentation caused by irrelevant variations, directly improving the cache hit ratio. This custom cache policy ensures that requests for the same 'v' value are served from the edge cache rather than forwarded to the origin.
Variation 2. Based on the exhibit, a media company serves versioned JavaScript and CSS files from an Amazon S3 origin through CloudFront. After a frontend release, the cache hit ratio dropped sharply even though the file names are versioned. The application team says the browser requests include the same Authorization header on every asset request because the frontend and API share one domain. What should the solutions architect do to improve CloudFront cache hit ratio without changing the application authentication model for the API?
hard
A.Enable S3 Transfer Acceleration on the bucket so CloudFront fetches objects faster from the origin.
✓ B.Create a CloudFront cache policy that excludes Authorization, cookies, and unnecessary query strings from the cache key.
C.Switch the origin from S3 to an Application Load Balancer so CloudFront can cache dynamic responses more effectively.
D.Configure CloudFront to forward every viewer header to the origin so the origin can decide whether the content is cacheable.
Why B: The sharp drop in cache hit ratio is caused by the Authorization header being included in the cache key, which makes each request unique even though the file names are versioned. By creating a CloudFront cache policy that excludes the Authorization header (and unnecessary cookies/query strings) from the cache key, CloudFront can serve cached responses to requests with different Authorization headers, restoring the cache hit ratio without altering the application's authentication model for the API.
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