incubator-cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Aaron Morton <aa...@thelastpickle.com>
Subject Re: atomicity
Date Sun, 19 Dec 2010 20:25:45 GMT
You need to keep on trying till it works :)

http://wiki.apache.org/cassandra/FAQ#batch_mutate_atomic

Aaron
On 20/12/2010, at 2:18 AM, Kevin Irwig <kevinirwig@yahoo.com> wrote:

> Thanks a lot, Peter.
> K.
> 
> 
> 
> ----- Original Message ----
> From: Peter Schuller <peter.schuller@infidyne.com>
> To: user@cassandra.apache.org
> Sent: Mon, 20 December, 2010 12:05:17 AM
> Subject: Re: atomicity
> 
>> Say I have two processes on separate machines, and a Cassandra cluster over
>> several machines. If the first process writes (insert) to a column while the
>> second process reads (get / get_slice / get_range_slices / others?) from that
>> column (say the consistency level is QUORUM if that makes a difference), is 
> the
>> write "atomic", or could the second process get corrupt (half-written) data?
>> What if Cassandra is not a cluster, but runs on a single machine? I'm 
> currently
>> using version 0.6.3, but the question is general.
> 
> You will never see an "in-between" value of a single column. You'd
> either see the old value or the new value.
> 
> However, given a batch mutation will multiple changes in it your
> readers may see the results of said batch mutation being partially
> applied; so there is no snapshot consistency type semantics with
> respect to multiple values in a batch mutation.
> 
> -- 
> / Peter Schuller
> 
> 
> 
> 

Mime
View raw message