test_metadata.py 文件源码

def test_nts_token_performance(self):
        """
        Tests to ensure that when rf exceeds the number of nodes available, that we dont'
        needlessly iterate trying to construct tokens for nodes that don't exist.

        @since 3.7
        @jira_ticket PYTHON-379
        @expected_result timing with 1500 rf should be same/similar to 3rf if we have 3 nodes

        @test_category metadata
        """

        token_to_host_owner = {}
        ring = []
        dc1hostnum = 3
        current_token = 0
        vnodes_per_host = 500
        for i in range(dc1hostnum):

            host = Host('dc1.{0}'.format(i), SimpleConvictionPolicy)
            host.set_location_info('dc1', "rack1")
            for vnode_num in range(vnodes_per_host):
                md5_token = MD5Token(current_token+vnode_num)
                token_to_host_owner[md5_token] = host
                ring.append(md5_token)
            current_token += 1000

        nts = NetworkTopologyStrategy({'dc1': 3})
        start_time = timeit.default_timer()
        nts.make_token_replica_map(token_to_host_owner, ring)
        elapsed_base = timeit.default_timer() - start_time

        nts = NetworkTopologyStrategy({'dc1': 1500})
        start_time = timeit.default_timer()
        nts.make_token_replica_map(token_to_host_owner, ring)
        elapsed_bad = timeit.default_timer() - start_time
        difference = elapsed_bad - elapsed_base
        self.assertTrue(difference < 1 and difference > -1)