Cassandra 3.0延迟统计不正确 [英] Cassandra 3.0 latency statistic incorrect

问题描述

我已经设置了新的Cassandra 3.3集群。然后，我使用jvisualvm通过MBean（jmx度量标准）监视Cassandra读/写延迟。

读/写延迟的结果在所有节点中始终稳定

当我使用jvisualvm监视Cassandra 2.0时，簇。读/写延迟具有正常行为。

我想知道为什么为什么Cassandra 3.0+的读/写延迟统计数据总是稳定的？我认为这是不正确的结果。 （我已经在Cassandra v3.3，v3.7中进行了负载测试。）

[更新]
我发现与该问题有关的错误。

Cassandra公制单位。 https://issues.apache.org/jira/browse/CASSANDRA-11752

详细信息表明，此问题已在C *版本2.2.8、3.0.9、3.8中解决。但是在3.0.9版中进行测试后，延迟的结果仍然显示为水平线。

任何想法？

谢谢。

解决方案

在使用C * 3.3时未发现任何度量标准问题

第一，尝试使用jconsole进行监视，遇到了相同的问题？

第二，您看到哪个属性？平均价值或百分比？总有价值从节点开始计数，因此通常会看到百分比值相同。但并非总是在平均值上发生。尝试重新启动cassandra节点并检查该值。

I have setup new Cassandra 3.3 cluster. Then I use jvisualvm to monitor Cassandra read/write latency by using MBean (jmx metric).

The result of read/write latency is always stable in all nodes for many weeks whereas read/write request in that cluster have normally movement (heavy or less in some day).

As I use jvisualvm to monitor Cassandra 2.0 cluster. The read/write latency have normally behavior. It have movement depending on read/wire requests.

I wonder that Why the read/write latency statistics of Cassandra 3.0+ are always stable? And I think it is incorrect result. (I have load tested in Cassandra v3.3, v3.7).

[Updated] I have found bug relate with this issue.

Cassandra metric flat. https://issues.apache.org/jira/browse/CASSANDRA-11752

The detail show that this problem has been solved in C* version 2.2.8, 3.0.9, 3.8. But after I have tested in version 3.0.9, The result of latency still show flat line.

Any Idea?

Thanks.

解决方案

have not found any metrics problem When using C*3.3

first,try to monitor with jconsole,have met same issue？

second,which attribute do you see?avg value or percentage?there value always count from node up,so it is common to see percentage value is same.but not always happens on average value.try to restart cassandra node and check the value.

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