ok got it. So, only using LWT txn the updates across nodes for a particular
row can be isolated, so basically paxos would ensure serializable isolation


On Wed, May 16, 2018 at 4:56 PM, kurt greaves <k...@instaclustr.com> wrote:

> Atomicity and isolation are only guaranteed within a replica. If you have
> multiple concurrent requests across replicas last timestamp will win. You
> can get better isolation using LWT which uses paxos under the hood.
> On 16 May 2018 at 08:55, Rajesh Kishore <rajesh10si...@gmail.com> wrote:
>> Hi,
>> I am just curious to know when Cassandra doc says the atomicity and
>> isolation is guaranteed for a row.
>> Does it mean, two requests updating a row- "R1" at different replica will
>> be candidate for atomicity and isolation?
>> For instance , I have a setup where RF is 2
>> I have a client application where two requests of updating a particular
>> row #R1 goes to two coordinator nodes at same time.
>> Row "R1" has presence in nodes - N1, N2 (since RF is 2)
>> Does Cassandra ensure atomicity & isolation across replicas/partition for
>> a particular row? If so , then how does it get handled does Cassandra
>> follows 2 Phase commit txn for a row or Cassandra uses distributed lock for
>> a row?
>> Thanks,
>> Rajesh

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