Why do I see "No cache policy was defined for this operation" in a sample trace?

This message appears when there are no Cache-Control HTTP headers in the response from the operation. These are set in Apollo Server via the @cacheControl directive.

To use the @cacheControl directive, you must add the following definitions to your server's schema:

enum CacheControlScope {
    PUBLIC
    PRIVATE
}

directive @cacheControl(
    maxAge: Int
    scope: CacheControlScope
    inheritMaxAge: Boolean
)   on FIELD_DEFINITION | OBJECT | INTERFACE | UNION

Whenever Apollo Server sends an operation response that has a non-zero maxAge, it includes a Cache-Control HTTP header that describes the response's cache policy.

The header has this format: Cache-Control: max-age=60, private

If you run Apollo Server behind a CDN or another caching proxy, you can configure it to use this header's value to cache responses appropriately.

You can find more information on caching here.