我在AWS上使用3节点RF3 Cassandra集群。 我将读取请求的超时设置为10ms。我注意到我的一些要求是超时的。这是我在CQL中使用TRACING ON观察到的内容;
Tracing session: 9fc1d420-9829-11e6-b04a-834837c1747b
activity | timestamp | source | source_elapsed | client
-------------------------------------------------------------------------------------------------------------------+----------------------------+---------------+----------------+-----------
Execute CQL3 query | 2016-10-22 10:32:02.274000 | 10.20.30.40 | 0 | 127.0.0.1
Parsing select * from recipes where id = fcc7d8b5-46d3-4867-903c-4a5c66a1fd2e; [Native-Transport-Requests-8] | 2016-10-22 10:32:02.274000 | 10.20.30.40 | 264 | 127.0.0.1
Preparing statement [Native-Transport-Requests-8] | 2016-10-22 10:32:02.274000 | 10.20.30.40 | 367 | 127.0.0.1
reading data from /10.20.0.1 [Native-Transport-Requests-8] | 2016-10-22 10:32:02.275000 | 10.20.30.40 | 680 | 127.0.0.1
Sending READ message to /10.20.0.1 [MessagingService-Outgoing-/10.20.0.1] | 2016-10-22 10:32:02.286000 | 10.20.30.40 | 12080 | 127.0.0.1
READ message received from /10.20.30.40 [MessagingService-Incoming-/10.20.30.40] | 2016-10-22 10:32:02.296000 | 10.20.0.1 | 51 | 127.0.0.1
Executing single-partition query on recipes [ReadStage-8] | 2016-10-22 10:32:02.298000 | 10.20.0.1 | 2423 | 127.0.0.1
Acquiring sstable references [ReadStage-8] | 2016-10-22 10:32:02.298000 | 10.20.0.1 | 2481 | 127.0.0.1
Skipped 0/4 non-slice-intersecting sstables, included 0 due to tombstones [ReadStage-8] | 2016-10-22 10:32:02.298000 | 10.20.0.1 | 2548 | 127.0.0.1
Bloom filter allows skipping sstable 55 [ReadStage-8] | 2016-10-22 10:32:02.298000 | 10.20.0.1 | 2614 | 127.0.0.1
Bloom filter allows skipping sstable 130 [ReadStage-8] | 2016-10-22 10:32:02.298000 | 10.20.0.1 | 2655 | 127.0.0.1
Bloom filter allows skipping sstable 140 [ReadStage-8] | 2016-10-22 10:32:02.298000 | 10.20.0.1 | 2704 | 127.0.0.1
Bloom filter allows skipping sstable 141 [ReadStage-8] | 2016-10-22 10:32:02.298001 | 10.20.0.1 | 2739 | 127.0.0.1
Merged data from memtables and 4 sstables [ReadStage-8] | 2016-10-22 10:32:02.298001 | 10.20.0.1 | 2796 | 127.0.0.1
Read 0 live and 0 tombstone cells [ReadStage-8] | 2016-10-22 10:32:02.298001 | 10.20.0.1 | 2854 | 127.0.0.1
Enqueuing response to /10.20.30.40 [ReadStage-8] | 2016-10-22 10:32:02.299000 | 10.20.0.1 | 2910 | 127.0.0.1
Sending REQUEST_RESPONSE message to /10.20.30.40 [MessagingService-Outgoing-/10.20.30.40] | 2016-10-22 10:32:02.302000 | 10.20.0.1 | 6045 | 127.0.0.1
REQUEST_RESPONSE message received from /10.20.0.1 [MessagingService-Incoming-/10.20.0.1] | 2016-10-22 10:32:02.322000 | 10.20.30.40 | 47911 | 127.0.0.1
Processing response from /10.20.0.1 [RequestResponseStage-42] | 2016-10-22 10:32:02.322000 | 10.20.30.40 | 48056 | 127.0.0.1
Request complete | 2016-10-22 10:32:02.323239 | 10.20.30.40 | 49239 | 127.0.0.1
在查看DataStax documentation时，似乎source_elapsed列是在源节点上发生事件之前经过的时间（以微秒为单位）。
从/10.20.30.40发送REQUEST_RESPONSE消息和从/10.20.0.1收到REQUEST_RESPONSE消息之间存在很大的时间差。
这是否表示存在网络延迟问题？