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From aaron morton <aa...@thelastpickle.com>
Subject Re: configure KeyCahce to use Non-Heap memory ?
Date Thu, 06 Sep 2012 23:29:14 GMT
The hit rate is pretty low 

> 0.451 recent hit rate,

A bigger cache would not help too much. 

Cheers


-----------------
Aaron Morton
Freelance Developer
@aaronmorton
http://www.thelastpickle.com

On 5/09/2012, at 11:31 PM, Ananth Gundabattula <agundabattula@threatmetrix.com> wrote:

> Hello Aaron,
> 
> Thanks a lot for the response. Raised a request https://issues.apache.org/jira/browse/CASSANDRA-4619
> 
> Here is the nodetool dump: (from one of the two nodes in the cluster) 
> 
> Token            : 0
> Gossip active    : true
> Thrift active    : true
> Load             : 147.64 GB
> Generation No    : 1346635362
> Uptime (seconds) : 182707
> Heap Memory (MB) : 4884.33 / 8032.00
> Data Center      : datacenter1
> Rack             : rack1
> Exceptions       : 0
> Key Cache        : size 777651120 (bytes), capacity 777651120 (bytes), 44354999 hits,
98275175 requests, 0.451 recent hit rate, 14400 save period in seconds
> Row Cache        : size 0 (bytes), capacity 0 (bytes), 0 hits, 0 requests, NaN recent
hit rate, 0 save period in seconds
> 
> 
> Number of rows in the 2 node cluster is 74+ Million
> 
> 
> 
> Regards,
> Ananth 
> 
> 
> 
> 
> From: aaron morton <aaron@thelastpickle.com>
> Reply-To: "user@cassandra.apache.org" <user@cassandra.apache.org>
> Date: Wednesday, September 5, 2012 11:33 AM
> To: "user@cassandra.apache.org" <user@cassandra.apache.org>
> Subject: Re: configure KeyCahce to use Non-Heap memory ?
> 
>> Is there any way I can configure KeyCahce to use Non-Heap memory ? 
> No.
> You could add a feature request here https://issues.apache.org/jira/browse/CASSANDRA
> 
> Could you post some stats on the current key cache size and hit rate ? (from nodetool
info) 
> It would be interesting to know how many keys it contains Vs the number of rows on the
box and the hit rate. 
> 
> Cheers
> 
> -----------------
> Aaron Morton
> Freelance Developer
> @aaronmorton
> http://www.thelastpickle.com
> 
> On 4/09/2012, at 3:01 PM, Ananth Gundabattula <agundabattula@threatmetrix.com>
wrote:
> 
>> 
>> Is there any way I can configure KeyCahce to use Non-Heap memory ? 
>> 
>> We have large memory nodes :  ~96GB memory per node and effectively using only  8
GB configured for heap ( to avoid GC issues because of a large heap) 
>> 
>> We have a constraint with respect to : 
>> Row cache models don't reflect our data query patterns and hence can only optimize
on the key cache 
>> Time constrained to change our schema to be more NO-SQL specific
>> 
>> 
>> Regards,
>> Ananth 
> 


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