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From John Lumby <johnlu...@hotmail.com>
Subject Re: is the select result grouped by the value of the partition key?
Date Wed, 11 Sep 2013 19:43:41 GMT
I would like to make quite sure about this implicit GROUP BY "feature",

since it seems really important yet does not seem to be mentioned in the
CQL reference documentation.



Aaron,   you said "yes"  --   is that "yes,  always,   in all scenarios no matter
what"

or "yes usually"?      Is it something we can bet the farm and farmer's family on?



The kinds of scenarios where I am wondering if it's possible for partition-key groups
to get intermingled are :



  .   what if the node containing primary copy of a row is down
                and 
cassandra fetches this row from a replica on a different node
               (e.g.  with CONSISTENCY ONE)

  .   what if there is a heavy stream of UPDATE activity from applications which
      connect to all nodes,   causing different nodes to have different versions of replicas
of same row?



Can you point me to some place in the cassandra source code where this grouping is ensured?



Many thanks,

John Lumby 		 	   		  
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