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Caching Config

Introduction

Hasura Cloud and Enterprise Edition provide support for caching query responses. This will drastically improve performance for queries which are executed frequently. This includes any GraphQL query including Actions and Remote Schemas.

Cached responses are stored for a period of time in a LRU (least-recently used) cache, and removed from the cache as per a user-specified TTL (time-to-live) which defaults to 60 seconds.

For self-hosted Enterprise Edition, refer to the enable caching documentation configure various parameters.

Getting started

In order to cache a query response, or to return an existing response from the cache (if one exists), simply add the @cached directive to your query:

query MyCachedQuery @cached {
  users {
    id
    name
  }
}

If the response was cached successfully, the HTTP response will include a Cache-Control header, whose value (max-age={SECONDS}) indicates the maximum number of seconds for the returned response to remain in the cache.

Controlling cache lifetime

The maximum lifetime of an entry in the cache can be controlled using the ttl argument to the @cached query directive. The value is an integer number of seconds:

query MyCachedQuery @cached(ttl: 120) {
  users {
    id
    name
  }
}

By default, a response will be cached with a maximum lifetime of 60 seconds. The maximum allowed value is 300 seconds (5 minutes).

:::info Limits for Hasura Cloud projects

As stated above, for any Hasura Cloud project, the maximum allowed value is 300 seconds (5 minutes). Should you need a longer cache lifetime, please contact sales.

:::

Forcing the cache to refresh

The cache entry can be forced to refresh, regardless of the maximum lifetime using the refresh argument to @cached. The value is a boolean:

query MyCachedQuery @cached(refresh: true) {
  users {
    id
    name
  }
}

:::info Use a literal boolean value for refresh

refresh must be provided with literal boolean value and not as a variable to have the desired effect. If the value of this refresh argument is provided via a GraphQL variable, then there would be a cache miss, as it is considered a different query and will generate a new cache key.

:::

Response headers

When you enable caching for a query, the following headers should be returned in the HTTP response:

• X-Hasura-Query-Cache-Key - Key for cached query response, unique to this query
• X-Hasura-Query-Family-Cache-Key - Key for the family of queries (ignores variable values)
• Cache-Control - Value: max-age={SECONDS} - Seconds until cache expires for query

These can be used by your application as you see fit, as well as by the cache-clearing endpoints.

Clearing items from the cache

A set of endpoints exist to clear items from the cache for the current project:

• POST /pro/cache/clear -- Clears all
• POST /pro/cache/clear?key={HASH} -- Clears key hash
• POST /pro/cache/clear?family={FAMILY} -- Clears items that match query family (ignoring variables)