I find under the src/client folder of Cassandra 2.1.0 source code, there is a *RingCache.java* file. It uses a thrift client calling the* describe_ring()* API to get the token range of each Cassandra node. It is used on the client side. The client can use it combined with the partitioner to get the target node. In this way there is no need to route requests between Cassandra nodes, and the client can directly connect to the target node. So maybe it can save some routing time and improve performance. Thank you very much.
2014-12-08 1:28 GMT+08:00 Jonathan Haddad <j...@jonhaddad.com>: > What's a ring cache? > > FYI if you're using the DataStax CQL drivers they will automatically > route requests to the correct node. > > On Sun Dec 07 2014 at 12:59:36 AM kong <kongjiali...@gmail.com> wrote: > >> Hi, >> >> I'm doing stress test on Cassandra. And I learn that using ring cache can >> improve the performance because the client requests can directly go to the >> target Cassandra server and the coordinator Cassandra node is the desired >> target node. In this way, there is no need for coordinator node to route >> the client requests to the target node, and maybe we can get the linear >> performance increment. >> >> >> >> However, in my stress test on an Amazon EC2 cluster, the test results are >> weird. Seems that there's no performance improvement after using ring >> cache. Could anyone help me explain this results? (Also, I think the >> results of test without ring cache is weird, because there's no linear >> increment on QPS when new nodes are added. I need help on explaining this, >> too). The results are as follows: >> >> >> >> INSERT(write): >> >> Node count >> >> Replication factor >> >> QPS(No ring cache) >> >> QPS(ring cache) >> >> 1 >> >> 1 >> >> 18687 >> >> 20195 >> >> 2 >> >> 1 >> >> 20793 >> >> 26403 >> >> 2 >> >> 2 >> >> 22498 >> >> 21263 >> >> 4 >> >> 1 >> >> 28348 >> >> 30010 >> >> 4 >> >> 3 >> >> 28631 >> >> 24413 >> >> >> >> SELECT(read): >> >> Node count >> >> Replication factor >> >> QPS(No ring cache) >> >> QPS(ring cache) >> >> 1 >> >> 1 >> >> 24498 >> >> 22802 >> >> 2 >> >> 1 >> >> 28219 >> >> 27030 >> >> 2 >> >> 2 >> >> 35383 >> >> 36674 >> >> 4 >> >> 1 >> >> 34648 >> >> 28347 >> >> 4 >> >> 3 >> >> 52932 >> >> 52590 >> >> >> >> >> >> Thank you very much, >> >> Joy >> >
