For this scenario, remove disk speed from the equation. Assume the row is completely in Row Cache. Also lets assume Read.ONE. With this information I would be looking to determine response size/maximum requests second/max latency.
I would use this to say "You want to do 5,000 reads/sec, on a GigaBit ethernet, and each row is 10K, in under 5ms latency" Sorry that is impossible. On Thu, Oct 25, 2012 at 2:58 PM, sankalp kohli <kohlisank...@gmail.com> wrote: > I dont have any sample data on this, but read latency will depend on these > 1) Consistency level of the read > 2) Disk speed. > > Also you can look at the Netflix client as it makes the co-ordinator node > same as the node which holds that data. This will reduce one hop. > > On Thu, Oct 25, 2012 at 9:04 AM, Edward Capriolo <edlinuxg...@gmail.com> > wrote: >> >> Hello all, >> >> Currently we implement wide rows for most of our entities. For example: >> >> user { >> event1=>x >> event2=>y >> event3=>z >> ... >> } >> >> Normally the entires are bounded to be less then 256 columns and most >> columns are small in size say 30 bytes. Because the blind write nature >> of Cassandra it is possible the column family can get much larger. We >> have very low latency requirements for example say less then (5ms). >> >> Considering network rountrip and all other factors I am wondering what >> is the largest column that is possible in a 5ms window on a GB >> network. First we have our thrift limits 15MB, is it possible even in >> the best case scenario to deliver a 15MB response in under 5ms on a >> GigaBit ethernet for example? Does anyone have any real world numbers >> with reference to package sizes and standard performance? >> >> Thanks all, >> Edward > >