我经历了冷到热（第一次使用）的集群和会话到本地数据源（Cassandra）需要640ms。任何额外的连接需要80到100ms，因此第一次连接的开销大约为500 + ms。这是正常的，有什么我可以做的，以某种方式得到这个数字？我用的是T410（i5 2.5GHz）。
[更新]
23:27:11.453 [main] DEBUG c.d.driver.core.SystemProperties - com.datastax.driver.NEW_NODE_DELAY_SECONDS is undefined, using default value 1
23:27:11.460 [main] DEBUG c.d.driver.core.SystemProperties - com.datastax.driver.NON_BLOCKING_EXECUTOR_SIZE is undefined, using default value 4
23:27:11.463 [main] DEBUG c.d.driver.core.SystemProperties - com.datastax.driver.NOTIF_LOCK_TIMEOUT_SECONDS is undefined, using default value 60
23:27:11.607 [main] DEBUG com.datastax.driver.core.Cluster - Starting new cluster with contact points [localhost/127.0.0.1:9042]
23:27:11.905 [main] DEBUG com.datastax.driver.core.Connection - Connection[localhost/127.0.0.1:9042-1, inFlight=0, closed=false] Transport initialized and ready
23:27:11.906 [main] DEBUG c.d.driver.core.ControlConnection - [Control connection] Refreshing node list and token map
23:27:11.969 [main] DEBUG c.d.driver.core.ControlConnection - [Control connection] Refreshing schema
23:27:12.016 [main] DEBUG c.d.driver.core.ControlConnection - [Control connection] Refreshing node list and token map
23:27:12.051 [main] DEBUG c.d.driver.core.ControlConnection - [Control connection] Successfully connected to localhost/127.0.0.1:9042
23:27:12.052 [main] INFO c.d.d.c.p.DCAwareRoundRobinPolicy - Using data-center name 'datacenter1' for DCAwareRoundRobinPolicy (if this is incorrect, please provide the correct datacenter name with DCAwareRoundRobinPolicy constructor)
23:27:12.053 [main] INFO com.datastax.driver.core.Cluster - New Cassandra host localhost/127.0.0.1:9042 added
23:27:12.076 [Cassandra Java Driver worker-0] DEBUG com.datastax.driver.core.Connection - Connection[localhost/127.0.0.1:9042-2, inFlight=0, closed=false] Transport initialized and ready
23:27:12.077 [Cassandra Java Driver worker-0] DEBUG com.datastax.driver.core.Session - Added connection pool for localhost/127.0.0.1:9042
23:27:12.097 [main] DEBUG com.datastax.driver.core.Connection - Connection[localhost/127.0.0.1:9042-2, inFlight=0, closed=true] closing connection
23:27:12.103 [main] DEBUG com.datastax.driver.core.Cluster - Shutting down
23:27:12.105 [main] DEBUG com.datastax.driver.core.Connection - Connection[localhost/127.0.0.1:9042-1, inFlight=0, closed=true] closing connection
23:27:12.123 [main] DEBUG com.datastax.driver.core.Cluster - Starting new cluster with contact points [/127.0.0.1:9042]
23:27:12.132 [main] DEBUG com.datastax.driver.core.Connection - Connection[/127.0.0.1:9042-1, inFlight=0, closed=false] Transport initialized and ready
23:27:12.132 [main] DEBUG c.d.driver.core.ControlConnection - [Control connection] Refreshing node list and token map
23:27:12.138 [main] DEBUG c.d.driver.core.ControlConnection - [Control connection] Refreshing schema
23:27:12.168 [main] DEBUG c.d.driver.core.ControlConnection - [Control connection] Refreshing node list and token map
23:27:12.192 [main] DEBUG c.d.driver.core.ControlConnection - [Control connection] Successfully connected to /127.0.0.1:9042
23:27:12.192 [main] INFO c.d.d.c.p.DCAwareRoundRobinPolicy - Using data-center name 'datacenter1' for DCAwareRoundRobinPolicy (if this is incorrect, please provide the correct datacenter name with DCAwareRoundRobinPolicy constructor)
23:27:12.192 [main] INFO com.datastax.driver.core.Cluster - New Cassandra host /127.0.0.1:9042 added
23:27:12.201 [Cassandra Java Driver worker-0] DEBUG com.datastax.driver.core.Connection - Connection[/127.0.0.1:9042-2, inFlight=0, closed=false] Transport initialized and ready
23:27:12.202 [Cassandra Java Driver worker-0] DEBUG com.datastax.driver.core.Session - Added connection pool for /127.0.0.1:9042
正如可以看到，第一次连接尝试最多使用600毫秒甚至更多，具体取决于人们如何读取数据。