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From "David Timothy Strauss" <da...@fourkitchens.com>
Subject Re: Off line client nodes?
Date Mon, 12 Apr 2010 20:50:12 GMT
It's not common for me to recommend CouchDB, but this is one instance it's great for: synching
complete datasets for disconnected use. Cassandra treats disconnection as a problem, not something
that should occur in the normal plan of operations.

-----Original Message-----
From: Colin Yates <colin.yates@gmail.com>
Date: Mon, 12 Apr 2010 10:52:32 
To: <user@cassandra.apache.org>
Subject: Off line client nodes?

Hi,

In our architecture, our consultants want to perform some
analysis on the train, disconnected from the web.  

How can I achieve this in Cassandra?  I realise this isn't quite
the use-case that was thought about when the clustering 
was designed, but will it work?

Scenario:

 - consultantA is in his office running a cassandra 
node on his laptop.

 - this node *very* periodically (almost on a manual basis) 
connects to the cluster and synchronises

 - consultant then gets some coffee

 - consultant then disconnects and sits on a train, happily 
using their app against the local node

 - consultant goes and plays golf whilst billing client for 
'management activities) (we know you do!) 

 - consultant plugs in at the end of the day and all changes are
synced back to the cluster

A few caveats:

 - the sync might not be atomic - the consultant *will* get bored
and disconnect before the sync has finished

 - the consultant should only see a tiny, well-defined fragment 
of the cluster data - i.e. a key range-set for example

Is this do-able or should I write a custom 'slurper' which
builds the local standalone client node?  I really don't want to do this....

Many thanks,

Col

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