Do you understand correctly that with cache-aside, we still need to go to the cache and invalidate data there when updating data in the database?

Yes, when using the cache-aside pattern, it is necessary to invalidate or update the corresponding data in the cache when updating data in the database.

This is because the cache and the database are two separate storage systems, and changing data in the database does not automatically update the cache. If the cache is not invalidated, stale data may be retrieved on the next request.

A typical approach:

1. Update the data in the database.
2. Delete (invalidate) the corresponding entry in the cache.

On the next request, data will be loaded from the database and written back to the cache.

Example in Go (simplified):

// Update data in the database
err := db.Update(key, newValue)
if err != nil {
    return err
}
// Invalidate the cache
cache.Delete(key)

Thus, the cache will always contain up-to-date data after the database is updated.