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 <kevinir...@yahoo.com> wrote: > Thanks a lot, Peter. > K. > > > > ----- Original Message ---- > From: Peter Schuller <peter.schul...@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 > > > >
