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From Alain Rastoul <>
Subject Re: Cassandra
Date Thu, 26 May 2016 02:40:52 GMT
On 25/05/2016 17:56, bastien dine wrote:
> Hi,
> I'm running a 3 nodes Cassandra 2.1.x cluster. Each node has 8vCPU and 30
> Go RAM.
> Replication factor = 3 for my keyspace.

> Is there a problem with the Java Driver ? The load balancing is not
Hi Bastien,

A replication factor of 3 for a 3 node cluster does not balance the 
load: since you ask for 3 copies of the data (rf=3) on 3 nodes cluster,
each node will have a copy of the data and you are overloading all nodes.
May be you should try with a rf = 2 or add nodes to your cluster ?

> "working" ? How can I list connections on a node ?
For a 3.x (I think also 2.x) you can trace  requests at the query level 
with enableTracing() method.
something like : (uncomment the line with .enableTracing() )

session.execute( boundedInsertEventStatement.bind( aggregateId, 
aggregateType, eventType, payload )
see the doc for other classes and tracing or consistency options,
and have a look at nodetool settraceprobability if you cannot change the 

The queries and query plans appear in the system_traces.sessions and tables. It can be very verbose for query plans 
(events table), may be you should truncate the sessions and events 
tables before running your load (on 3.x tables are  truncated on startup)

> Regards,
> Bastien


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