Maximize Cache Hit Ratios with ESA Global Cache Policies & TTL Controls - Edge Security Acceleration

Configure a global cache policy for static resources. This caches static resources at edge nodes to improve cache hit rates, accelerate client access, and reduce back-to-origin traffic.

Note

If you do not set any cache rules or cache configurations, the caching logic of Edge Security Acceleration (ESA) POPs follows the default cache rule.

Feature	Description
Query String	When a point of presence (POP) processes a user request to generate a cache key, you can configure it to remove the `?` and the query string that follows the `?`, such as user identity information and access channel source, from the request URL. This enables request URLs with different parameters to reference the same cache file, improving the cache hit ratio and reducing page load time.
Browser Cache Time-to-Live (TTL)	Browser cache time-to-live (TTL) defines how long resources (such as HTML, CSS, JavaScript files, and images) are stored in the local browser cache. By default, it follows the `Cache-Control` header settings of the origin. You can configure the client TTL without modifying the origin settings. This allows resources within the validity to be loaded directly from the local cache. This speeds up page loading and improves user experience.
Edge Cache Time-to-Live (TTL)	The edge cache time-to-live (TTL) is the period of time during which origin resources are cached on Edge Security Acceleration (ESA) points of presence (POPs). When the TTL ends, resources that are cached on POPs are marked as expired. If the requested resource has expired on a POP, the POP retrieves the most recent resource from the origin server and caches it. You can configure a cache TTL for static resources based on file directories or file name extensions. This reduces the load on the origin server and improves access performance.
Development Mode	Enable development mode to ensure that clients can immediately retrieve the latest static resources. When this mode is enabled, static resource requests temporarily bypass the caching components of Edge Security Acceleration (ESA) and are forwarded directly to the origin server. This lets you verify changes to your origin content.
Query String Sorting	When you enable the query string sorting feature, Edge Security Acceleration (ESA) automatically sorts the query string parameters in a URL when processing a request. ESA then uses the sorted query string to look up content in the cache or forward the request. This means that a point of presence (POP) treats requests as being for the same file if the parameters and their values are identical, regardless of their order in the URL. This feature helps improve the cache hit ratio.

Mapping between site-level features and rule-based features

Settings added under site-level global features apply to all requests for that site. To apply a feature only to specific requests, use rule-based features. Define conditions in your rules to detect specific parameters in user requests. This gives you precise control over which requests the rule applies to.

Site-level feature	Corresponding rule-based feature
Query String	Custom Cache Key
Query String Sorting	Custom Cache Key
Browser Cache Time-to-Live (TTL)	Browser Cache Time-to-Live (TTL)
Edge Cache Time-to-Live (TTL)	Edge Cache Time-to-Live (TTL)
Cache Reservation	Cache Reserve