Custom marketing query parameters cause cache misses
In AEMaaCS, campaign URLs that include custom marketing query parameters can reduce CDN and Dispatcher cache efficiency. This happens because the full request URL, including query parameters, becomes part of the cache key unless those parameters are removed or ignored consistently at the caching layers. Standard marketing parameters may already be handled, but custom parameters such as elq_cid can still create separate cache entries and increase origin traffic. Review the CDN and Dispatcher configuration so custom marketing parameters no longer fragment cache entries.
Description description
Environment
- Adobe Experience Manager as a Cloud Service (AEMaaCS)
- Adobe-managed CDN or customer-managed CDN
- Dispatcher
Symptoms
- Cache hit ratio drops during campaign traffic.
- Requests that differ only by parameters such as
elq_cidor similar tracking values do not reuse the same cached response. - Origin traffic increases even though the page content does not change based on the query parameter.
- Dispatcher ignores some parameters, but cache fragmentation still continues because the CDN layer is not handling them in the same way.
Cause
The CDN cache key includes the full request URL, including query parameters. If custom marketing parameters are not removed or normalized at the CDN layer, each unique parameter value creates a separate cache entry. Dispatcher can reduce cache fragmentation by ignoring selected query parameters, but it cannot fully protect cache efficiency if the CDN or a customer-managed CDN still treats those parameters as unique request variants.
Resolution resolution
To resolve cache misses caused by custom marketing query parameters, follow these steps:
- Identify the custom marketing query parameters that do not change the page response, such as
elq_cidor similar campaign tracking values. - Review the CDN configuration and ensure that those parameters are removed or normalized before they become part of the cache key.
- If you use a customer-managed CDN, configure equivalent rules there so the CDN does not treat those custom parameters as unique cache variants.
- Review the Dispatcher configuration and add the same non-functional marketing parameters to
ignoreUrlParamswhere appropriate. - Deploy the CDN and Dispatcher configuration changes.
- Retest requests for the same page with different custom marketing parameter values and confirm that the cache hit ratio improves.
- If cache fragmentation continues after the configuration changes, contact Adobe Support and share the affected parameter names, request examples, and cache behavior.