I was about to ask what Anthony's latest post below captures - if we don't have vector clocks and no locking, how does cassandra prevent/detect conflicts? This is somewhat related to the question I asked in last post - http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/How-does-Cassandra-handle-failure-during-synchronous-writes-td6055152.html
<http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/How-does-Cassandra-handle-failure-during-synchronous-writes-td6055152.html> Thanks, Ritesh On Wed, Feb 23, 2011 at 6:22 PM, Anthony John <chirayit...@gmail.com> wrote: > Apologies : For some reason my response on the original mail keeps bouncing > back, thus this new one! > > From the other hand, the same article says: > > "For conditional writes to work, the condition must be evaluated at all > update > > sites before the write can be allowed to succeed." > > > > This means, that when doing such an update CL=ALL must be used > > Sorry, but I am confused by that entire thread! > > Questions:- > 1. Does Cassandra implement any kind of data locking - at any granularity > whether it be row/colF/Col ? > 2. If the answer to 1 above is NO! - how does CL ALL prevent conflicts. > Concurrent updates on exactly the same piece of data on different nodes can > still mess each other up, right ? > > -JA >
