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From Dave Brosius <>
Subject Re: Loading data on-demand in Cassandra
Date Sun, 12 Aug 2012 19:39:10 GMT
When data is first written it does remain in memory until that memory is 
flushed. After the data is only on disk, it remains there until a read 
for that row-key/column is requested so in essense it's always load on 

Currently there is no support for async notifications of changes.

On 08/12/2012 03:24 PM, Oliver Plohmann wrote:
> Hello,
> I'm looking a bit into Cassandra to see whether it would be something 
> to go with for my company. I searched through the Internet, looked 
> through the FAQs, etc. but there are still some few open questions. 
> Hope I don't bother anybody with the usual beginner questions ...
> Is there a way to do load-on-demand of data in Cassandra? For the time 
> being, we cannot afford to built up a cluster that holds our 700 GB 
> SQL-Database in RAM. So we need to be able to load data on-demand from 
> our relational database. Can this be done in Cassandra? Then there 
> also needs to be a way to unload data in order to reclaim RAM space. 
> Would be nice if it were possible to register for an asynchronous 
> notification in case some value was changed. Can this be done?
> Thanks for any answers.
> Regards, Oliver

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