I haven't been very accurate in my first answer indeed, which was
misleading.
Apache Cassandra guarantees that if all queries are ran at least at quorum,
a client writing successfully (as in the cluster acknowledged the write)
then reading his previous write will see the correct value unless anothe
On Wed, Sep 14, 2016 at 3:49 PM, Nicolas Douillet <
nicolas.douil...@gmail.com> wrote:
> -
> - during read requests, cassandra will ask to one node the data and to
> the others involved in the CL a digest, and if all digests do not match,
> will ask for them the entire data, handle the merge and f
Hi,
In my opinion the guaranty provided by Cassandra is :
if your write request in Quorum *succeed*, then the next (after the
write response) read requests in Quorum (that succeed too) will be
consistent
(actually CL.Write + CL.Read > RF)
Of course while you haven't received a valid r
My understanding of the described scenario is that the write hasn't
succeeded when reads are fired, as B and C haven't processed the mutation
yet.
There would be 3 clients here and not 2 : C1 writes, C2 and C3 read.
So the race condition could still happen in this particular case.
Le mer. 14 sep
Hi Alex:
Hmmm ... Assuming clock skew is eliminated And assuming nodes are up and
available ... And assuming quorum writes and quorum reads and everyone waiting
for success ( which is NOT The OP scenario), Two different clients will be
guaranteed to see all successful writes, or be told tha
Hi,
the analysis is valid, and strong consistency the Cassandra way means that
one client writing at quorum, then reading at quorum will always see his
previous write.
Two different clients have no guarantee to see the same data when using
quorum, as illustrated in your example.
Only options here
hi all,
we are using quorum consistency, and we *suspect* there may be a race
condition during the write. lets say RF is 3. so write will wait for at
least 2 nodes to ack. suppose there is only 1 node acked(node A). the other
2 nodes(node B, C) are still waiting to update. there come two read requ
