Like Edward says Cassandra's conflict resolution strategy is LWW (last write wins). This may seem simplistic, but Cassandra's Big Query-esque data model makes it less of an issue than in a pure key/value-store like Riak, for example. When all you have is an opaque value for a key you want to be able to do things like keeping conflicting writes so that you can resolve them later. Since Cassandra's rows aren't opaque, but more like a sorted map LWW is almost always enough. With Cassandra you can add new columns/cells to a row from multiple clients without having to worry about conflicts. It's only when multiple clients write to the same column/cell that there is an issue, but in that case you usually can (and you probably should) model your way around that.
T# On Fri, Jun 7, 2013 at 4:51 PM, Edward Capriolo <edlinuxg...@gmail.com>wrote: > Conflicts are managed at the column level. > 1) If two columns have the same name the column with the highest timestamp > wins. > 2) If two columns have the same column name and the same timestamp the > value of the column is compared and the highest* wins. > > Someone correct me if I am wrong about the *. I know the algorithm is > deterministic, I do not remember if it is highest or lowest. > > > On Thu, Jun 6, 2013 at 6:25 PM, Emalayan Vairavanathan < > svemala...@yahoo.com> wrote: > >> I tried google and found conflicting answers. Thats why wanted to double >> check with user forum. >> >> Thanks >> >> ------------------------------ >> *From:* Bryan Talbot <btal...@aeriagames.com> >> *To:* user@cassandra.apache.org; Emalayan Vairavanathan < >> svemala...@yahoo.com> >> *Sent:* Thursday, 6 June 2013 3:19 PM >> *Subject:* Re: [Cassandra] Conflict resolution in Cassandra >> >> For generic questions like this, google is your friend: >> http://lmgtfy.com/?q=cassandra+conflict+resolution >> >> -Bryan >> >> >> On Thu, Jun 6, 2013 at 11:23 AM, Emalayan Vairavanathan < >> svemala...@yahoo.com> wrote: >> >> Hi All, >> >> Can someone tell me about the conflict resolution mechanisms provided by >> Cassandra? >> >> More specifically does Cassandra provides a way to define application >> specific conflict resolution mechanisms (per row basis / column basis)? >> or >> Does it automatically manage the conflicts based on some synchronization >> algorithms ? >> >> >> Thank you >> Emalayan >> >> >> >> >> >> >
