I suspect some of the intermediate queries (determining role, etc) happen at quorum in 2.2+, but I don’t have time to go read the code and prove it.
In any case, RF > 10 per DC is probably excessive Also want to crank up the validity times so it uses cached info longer -- Jeff Jirsa > On Nov 23, 2018, at 10:18 AM, Vitali Dyachuk <[email protected]> wrote: > > no its not a cassandra user and as i understood all other users login > local_one. > >> On Fri, 23 Nov 2018, 19:30 Jonathan Haddad <[email protected] wrote: >> Any chance you’re logging in with the Cassandra user? It uses quorum reads. >> >> >>> On Fri, Nov 23, 2018 at 11:38 AM Vitali Dyachuk <[email protected]> wrote: >>> Hi, >>> We have recently met a problem when we added 60 nodes in 1 region to the >>> cluster >>> and set an RF=60 for the system_auth ks, following this documentation >>> https://docs.datastax.com/en/cql/3.3/cql/cql_using/useUpdateKeyspaceRF.html >>> However we've started to see increased login latencies in the cluster 5x >>> bigger than before changing RF of system_auth ks. >>> We have casandra runner written is csharp, running against the cluster, >>> when analyzing the logs we notices that Rebuilding token map is taking >>> most of the time ~20s. >>> When we changed RF to 3 the issue has resolved. >>> We are using C* 3.0.17 , 4 DC, system_auth RF=3, "CassandraCSharpDriver" >>> version="3.2.1" >>> I've found somehow related to my problem ticket >>> https://datastax-oss.atlassian.net/browse/CSHARP-436 but it says in the >>> related tickets, that the issue with the token map rebuild time has been >>> fixed in the previous versions of the driver. >>> So my question is what is the best recommendation of the setting >>> system_auth ks RF? >>> >>> Regards, >>> Vitali Djatsuk. >>> >>> >> -- >> Jon Haddad >> http://www.rustyrazorblade.com >> twitter: rustyrazorblade
