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https://issues.apache.org/jira/browse/CASSANDRA-12257?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15426141#comment-15426141
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stone commented on CASSANDRA-12257:
-----------------------------------
dont think this is same thing.
Cassandra-11752 && Cassandra-11569 just get the cross-datacenter latency.what i
want are more than this.
1.I want to get latency of the record replicated to another datacenter.
2.need to query this latency with a certain time,which mean that may need to
persist this latency value.
3.want to know the latency of cross datacenter replicate latency.so if we
depends on application.it may not work well.for instance,at a time,we have not
receive replicate from other datacenter,but we dont know the reason is no write
request,or large latency.
so need a standalone mechanism to detect this
> data consistency of multi datacenter
> -------------------------------------
>
> Key: CASSANDRA-12257
> URL: https://issues.apache.org/jira/browse/CASSANDRA-12257
> Project: Cassandra
> Issue Type: Improvement
> Components: Coordination
> Reporter: stone
>
> Environment:
> serveral active-active cassandra datacenter.
> set write consistency level=local_quorum to get a high resquest response.
> Concern:
> we dont know the time of the data arrive other datacenter.
> we dont know the size of data that need to be transferred to other
> datacenter.
> Thought:
> 1.we can get the latency with ping or other monitor tool,but it can not
> represent the latency of cassandra data to be transferred from one dc to
> another dc.
> 2.we can measure the latency between dc.but there is a accumulated value from
> node started,it cannot represent the latency now.
> https://issues.apache.org/jira/browse/CASSANDRA-11569
> Scenanio:
> one project need to collect information from sensors,which in different
> region.2 datacenter,DC1,DC2.sensor1,sensor2 in DC1 region.sensor3,sensor4 in
> DC2.
> one client in DC1,pull data every 10 minutes.
> 1.sensor3 in DC2 write a record to DC2 at 8:59:55 ,and arrived DC1 at 9:00:05
> 2.client in DC1 pull data at 9:00,it should get the record,but it cannot as
> the
> record have not arrive DC1.
> 3.then client in DC1 will pull data at 9:10.it also can not get the record as
> it will pull data from 9:00---9:10,but the record created on 8:59:55
> so we will miss the record.
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