You're looking at v2 documentation. The current version is v3.
You can find the docs for the current version here.
Cached Tenant Lookup
If you're using the database storage driver, you may want to cache tenant lookup (domain -> tenant id -> Tenant object mapping). Running DB queries on each request to identify the tenant is somewhat expensive, as a separate database connection has to be established.
To avoid this, you may want to enable caching.
You may enable this feature by setting the tenancy.storage_drivers.db.cache_store config key to the name of your cache store (e.g. redis), and optionally setting cache_ttl (default is 3600 seconds).
The cache invalidation of course happens automatically, as long as you modify your tenants using Tenant objects and not direct DB calls.