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From Rob Coli <rc...@digg.com>
Subject Re: Ring management and load balance
Date Fri, 26 Mar 2010 21:28:24 GMT
On 3/26/10 1:36 PM, Roland Hänel wrote:
> If I was going to write such a tool: do you think the thrift API
> provides the necessary information? I think with the RandomPartitioner
> you cannot scan all your rows to actually find out how big certain
> ranges of rows are. And even with the OPP (that is the major target for
> this kind of tool, for sure) you would have to fetch all row's content
> just to find out how large it is, right?

The JMX interface exposes an Attribute which seems appropriate to this 
use. It is called "TotalDiskSpaceUsed," and is available on a 
per-columnfamily basis. Given a CF called "Users" in a Keyspace called 
"MyKeyspace", it is accessible at :

"
org.apache.cassandra.db:type=ColumnFamilyStores,keyspace=MyKeyspace,columnfamily=Users
"

Unfortunately, I have yet to document the per-CF "ColumnFamilyStores" 
and "Caches" JMX interface Attributes and Operations, including this 
one. But when I do so, I will do it here :

http://wiki.apache.org/cassandra/JmxInterface

=Rob

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