pools

# File activerecord/lib/active_record/connection_adapters/abstract/connection_pool/reaper.rb, line 56
          def pools(refs = nil) # :nodoc:
            refs ||= @mutex.synchronize { @pools.values.flatten(1) }

            refs.filter_map do |ref|
              ref.__getobj__ if ref.weakref_alive?
            rescue WeakRef::RefError
            end.select(&:maintainable?)
          end