More a less yes you must handle the synchronization, this only really becomes an issue when multiple hosts hit Cassandra and want to hit the same row/column at the same time, which is certainly possible but may not be common depending on your use case.
this has a bit of info on the column level clock http://wiki.apache.org/cassandra/DataModel you can write your own clock resolution in a high level client like hector http://patricioechague.blogspot.com/2010/12/how-to-create-custom-clockresolution-in.html single writer timestamp resolution http://patricioechague.blogspot.com/2010/10/evaluating-timestamp-resolution.html Vector clocks was more of a Dynamo thing, I read a write up somewhere on some of reasons why Cassandra puts this issue on the user but I can't locate it currently unfortunately. Hope this helps. -----Original Message----- From: tijoriwala.ritesh [mailto:tijoriwala.rit...@gmail.com] Sent: Tuesday, February 22, 2011 8:13 PM To: cassandra-u...@incubator.apache.org Subject: Re: Does Cassandra use vector clocks Thanks for the quick reply. I found this ticket https://issues.apache.org/jira/browse/CASSANDRA-580 which talks about vector clock support in Cassandra but it was marked as "won't fix". It would be insightful to know why it was rejected. If Cassandra relies on timestamps, does it mean that clients have to be clock synchronized? This is very difficult in distributed systems. -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Does-Cassandra-use-vector-clocks-tp6054778p6054806.html Sent from the cassandra-u...@incubator.apache.org mailing list archive at Nabble.com. _______________________________________________ This e-mail may contain information that is confidential, privileged or otherwise protected from disclosure. If you are not an intended recipient of this e-mail, do not duplicate or redistribute it by any means. Please delete it and any attachments and notify the sender that you have received it in error. Unless specifically indicated, this e-mail is not an offer to buy or sell or a solicitation to buy or sell any securities, investment products or other financial product or service, an official confirmation of any transaction, or an official statement of Barclays. Any views or opinions presented are solely those of the author and do not necessarily represent those of Barclays. This e-mail is subject to terms available at the following link: www.barcap.com/emaildisclaimer. By messaging with Barclays you consent to the foregoing. Barclays Capital is the investment banking division of Barclays Bank PLC, a company registered in England (number 1026167) with its registered office at 1 Churchill Place, London, E14 5HP. This email may relate to or be sent from other members of the Barclays Group. _______________________________________________
