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From "Konstantin Naryshkin" <konstant...@a-bb.net>
Subject Re: Question about sharding of rows and atomicity
Date Wed, 05 Oct 2011 18:17:22 GMT
Cassandra does not break apart a row. All of the columns of a row are kept on the same nodes.

I believe that writing multiple columns of the same row is transactional, but not atomic.
By which I mean that if one column is written all the other ones will be written as well,
but if a read happens while the write is being done it is possible that only some of the columns
will have the new values.

----- Original Message -----
From: "Don Smith" <dsmith@likewise.com>
To: user@cassandra.apache.org
Sent: Wednesday, October 5, 2011 2:09:36 PM
Subject: Question about sharding of rows and atomicity

Does Cassandra shard the columns of a single row across multiple nodes 
so that to read the columns of the row it may need access to multiple 
nodes?   I'd say "no."   Will a read from a given node ever return 
partial results or is the write to a node of a row atomic?

  Thanks, Don



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