module ActiveRecord::QueryCache::ClassMethods

def cache(&block)

If it's not, it will execute the given block.
Enable the query cache within the block if Active Record is configured. 
def cache(&block)
  if connected? || !configurations.empty?
    pool = connection_pool
    was_enabled = pool.query_cache_enabled
    begin
      pool.enable_query_cache(&block)
    ensure
      pool.clear_query_cache unless was_enabled
    end
  else
    yield
  end
end

def uncached(dirties: true, &block)

(By default, write operations dirty all connections' query caches in case they are replicas whose cache would now be outdated.)
Set dirties: false to prevent query caches on all connections from being cleared by write operations.

If it's not, it will execute the given block.
Disable the query cache within the block if Active Record is configured. 
def uncached(dirties: true, &block)
  if connected? || !configurations.empty?
    connection_pool.disable_query_cache(dirties: dirties, &block)
  else
    yield
  end
end