Hmm... ok. Ideally, we require ::
a) The intra-DC-node-syncing takes place at the statement/query level. b) The inter-DC-node-syncing takes place at cassandra level. That way, we don't spend too much delay at the statement/query level. For the so-called CAS/lightweight transactions, the above are impossible then? On Wed, Nov 4, 2015 at 5:58 AM, Bryan Cheng <br...@blockcypher.com> wrote: > What Eric means is that SERIAL consistency is a special type of > consistency that is only invoked for a subset of operations: those that use > CAS/lightweight transactions, for example "IF NOT EXISTS" queries. > > The differences between CAS operations and standard operations are > significant and there are large repercussions for tunable consistency. The > amount of time such an operation takes is greatly increased as well; you > may need to increase your internal node-to-node timeouts . > > On Mon, Nov 2, 2015 at 8:01 PM, Ajay Garg <ajaygargn...@gmail.com> wrote: > >> Hi Eric, >> >> I am sorry, but I don't understand. >> >> If there had been some issue in the configuration, then the >> consistency-issue would be seen everytime (I guess). >> As of now, the error is seen sometimes (probably 30% of times). >> >> On Mon, Nov 2, 2015 at 10:24 PM, Eric Stevens <migh...@gmail.com> wrote: >> >>> Serial consistency gets invoked at the protocol level when doing >>> lightweight transactions such as CAS operations. If you're expecting that >>> your topology is RF=2, N=2, it seems like some keyspace has RF=3, and so >>> there aren't enough nodes available to satisfy serial consistency. >>> >>> See >>> http://docs.datastax.com/en/cassandra/2.0/cassandra/dml/dml_ltwt_transaction_c.html >>> >>> On Mon, Nov 2, 2015 at 1:29 AM Ajay Garg <ajaygargn...@gmail.com> wrote: >>> >>>> Hi All. >>>> >>>> I have a 2*2 Network-Topology Replication setup, and I run my >>>> application via DataStax-driver. >>>> >>>> I frequently get the errors of type :: >>>> *Cassandra timeout during write query at consistency SERIAL (3 replica >>>> were required but only 0 acknowledged the write)* >>>> >>>> I have already tried passing a "write-options with LOCAL_QUORUM >>>> consistency-level" in all create/save statements, but I still get this >>>> error. >>>> >>>> Does something else need to be changed in /etc/cassandra/cassandra.yaml >>>> too? >>>> Or may be some another place? >>>> >>>> >>>> -- >>>> Regards, >>>> Ajay >>>> >>> >> >> >> -- >> Regards, >> Ajay >> > > -- Regards, Ajay
