Hello Evan Why, in a scenario of resurrections of unacknowledged writes, don't we get linearizability ? Can you give more detailed explanation on such scenario ?
@Oliver: true, the formal definition of linearizability is not related to isolation. My bad. And for your question "What does Cassandra do in the case of inconsistent reads? Wait or report failure? I could not find that one in the docs. ", if you're reading at CL >= QUORUM, Cassandra will repair the data before sending the good result (good = data with latest timestamp, last write win rule) to the client. Regards On Thu, Oct 16, 2014 at 7:16 PM, Evan Weaver <[email protected]> wrote: > Quorum reads and writes in Cassandra guarantee sequential consistency. > The reason this doesn't satisfy linearizability is because > resurrections of unacknowledged writes can occur. A read of a > half-committed write will trigger synchronous read repair and the > order will be stable from that point forward. > > Isolation is an unrelated issue. > > Evan > > On Wed, Oct 15, 2014 at 4:45 PM, Timmy Turner <[email protected]> wrote: > > Cassandra in general can't provide guarantee any ordering of the executed > > queries, since nodes may fail or rejoin the in arbitrary points in time. > > > > But why can't it provide ordering for queries run at at least the quorum > > level? Given that none of the updates get lost, why would order still an > > issue? > > > > Can you maybe illustrate a scenario which shows how/where the order would > > get lost if writes and reads always occurred with quorum consistency? >
