add hint on scheduled task for delayed cache invalidation (#1619)

* add hint on scheduled task for delayed cache invalidation

* Fix links

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Co-authored-by: Micha <[email protected]>

guides/hosting/performance/performance-tweaks.md

@@ -38,12 +38,16 @@ shopware:
 A delay for cache invalidation can be activated for systems with a high update frequency for the inventory (products, categories). Once the instruction to delete the cache entries for a specific product or category occurs, they are not deleted instantly but processed by a background task later. Thus, if two processes invalidate the cache in quick succession, the timer for the invalidation of this cache entry will only reset.
 By default, the scheduled task will run every 20 seconds, but the interval can be adjusted over the `scheduled_taks` DB table, by setting the `run_interval` to the desired value (it is configured in seconds) for the entry with the name `shopware.invalidate_cache`.
 
+::: warning
+If you enable delayed cache invalidation, you must set up a worker to run [Scheduled Tasks](../infrastructure/scheduled-task), e.g., using the [Message Queue](../infrastructure/message-queue).
+:::
+
 ```yaml
 # config/packages/prod/shopware.yaml
 shopware:
     cache:
         invalidation:
-            delay: 1
+            delay: 1 # 0 = disabled, 1 = enabled
             delay_options:
                 storage: redis
                 connection: 'ephemeral' # connection name from redis configuration