clear_cache!

# File activerecord/lib/active_record/connection_adapters/abstract/connection_specification.rb, line 104
        def clear_cache!(cache, thread_id = nil, &block)
          if cache
            if @@allow_concurrency
              thread_id ||= Thread.current.object_id
              thread_cache, cache = cache, cache[thread_id]
              return unless cache
            end

            cache.each(&block) if block_given?
            cache.clear
          end
        ensure
          if thread_cache && @@allow_concurrency
            thread_cache.delete(thread_id)
          end
        end