Actually maybe I'll open a JIRA issue for a (local)quorum_or_one consistency level... It should be trivial to implement on server side with exist timeouts ... I'll need to check the CQL protocol to see if there is a good place to indicate you didn't reach quorum (in time)
Sent from my iPhone > On Oct 9, 2015, at 8:02 PM, Graham Sanderson <gra...@vast.com> wrote: > > Most of our writes are not user facing so local_quorum is good... We also > read at local_quorum because we prefer guaranteed consistency... But we very > quickly fall back to local_one in the cases where some data fast is better > than a failure. Currently we do that on a per read basis but we could I > suppose detect a pattern or just look at the gossip to decide to go en masse > into a degraded read mode > > Sent from my iPhone > >> On Oct 9, 2015, at 5:39 PM, Steve Robenalt <sroben...@highwire.org> wrote: >> >> Hi Brice, >> >> I agree with your nit-picky comment, particularly with respect to the OP's >> emphasis, but there are many cases where read at ONE is sufficient and >> performance is "better enough" to justify the possibility of a wrong result. >> As with anything Cassandra, it's highly dependent on the nature of the >> workload. >> >> Steve >> >> >>> On Fri, Oct 9, 2015 at 12:36 PM, Brice Dutheil <brice.duth...@gmail.com> >>> wrote: >>>> On Fri, Oct 9, 2015 at 2:27 AM, Steve Robenalt <sroben...@highwire.org> >>>> wrote: >>>> >>>> In general, if you write at QUORUM and read at ONE (or LOCAL variants >>>> thereof if you have multiple data centers), your apps will work well >>>> despite the theoretical consistency issues. >>> >>> Nit-picky comment : if consistency is something important then reading at >>> QUORUM is important. If read is ONE then the read operation may not see >>> important update. The safest option is QUORUM for both write and read. Then >>> depending on the business or feature the consistency may be tuned. >>> >>> — Brice >>> >> >> >> >> -- >> Steve Robenalt >> Software Architect >> sroben...@highwire.org >> (office/cell): 916-505-1785 >> >> HighWire Press, Inc. >> 425 Broadway St, Redwood City, CA 94063 >> www.highwire.org >> >> Technology for Scholarly Communication
