Skip to main content

Cache Control

Cache Control policies optimize content delivery performance by configuring Time to Live (TTL) settings and cache behavior options. These policies enhance CDN hit ratios and reduce origin server load.

![Figure Needed] Screenshot showing cache control policy configuration interface

Cache Configuration Options​

Time to Live (TTL)​

The duration in seconds that resources are cached on the CDN system to serve users. Proper TTL configuration balances content freshness with performance optimization.

Ignore Origin Server No Cache​

Removes cache-control headers like "no-cache" and "no-store" from origin server responses, allowing CDN caching even when origin servers specify no caching.

Ignore Client No Cache​

Removes the "no-cache" header from client requests, preventing clients from bypassing CDN cache with cache-busting requests.

Ignore Query String​

Ignores query strings during cache storage, significantly increasing the HIT ratio on the CDN by treating URLs with different parameters as the same cached resource.

Cache Optimization Benefits​

These options enhance CDN HIT ratio performance, with "Ignore Query String" providing particularly significant improvements. However, implementation depends on website operational requirements.

Query String Behavior Example​

When "Ignore Query String" is enabled, the CDN system provides the same cached data for all variations of a URL:

  • http://www.example.com/path/to/photo.jpg
  • http://www.example.com/path/to/photo.jpg?clientId=12345&product=A123
  • http://www.example.com/path/to/photo.jpg?clientId=67890&product=A456

All three URLs will serve the same cached version of photo.jpg.

Policy Application​

URL Pattern Matching​

Cache policies are applied to resources based on URL patterns using:

  • Prefix Matching: Applies to URLs starting with specified path
  • Suffix Matching: Applies to URLs ending with specified extension
  • Regular Expression Matching: Complex pattern matching for advanced use cases

Policy Priority​

When multiple cache policies match a URL, the most specific policy takes precedence:

  1. Longest prefix match
  2. Most specific regular expression pattern
  3. Default cache behavior if no policies match

Implementation Considerations​

Content Type Suitability​

  • Static Assets: Images, CSS, JavaScript files benefit from longer TTL values
  • Dynamic Content: API responses, user-specific content require shorter TTL or cache bypass
  • Frequently Updated Content: News, real-time data need careful TTL configuration

Website Compatibility​

Before enabling cache optimization options, consider:

  • Dynamic Parameter Handling: Whether query parameters affect content delivery
  • User-Specific Content: Personalized content that should not be shared
  • Cache Invalidation Requirements: How frequently content updates occur

Performance Monitoring​

Cache Hit Ratio Tracking​

Monitor cache effectiveness through analytics:

  • Request Hit Ratio: Percentage of requests served from cache
  • Byte Hit Ratio: Percentage of bytes served from cache
  • Origin Offload: Reduction in origin server requests

Optimization Recommendations​

  • Start with conservative TTL values and increase based on performance data
  • Monitor cache hit ratios after policy changes
  • Use ignore query string carefully to avoid serving incorrect content
  • Test policies thoroughly before production deployment