The column family specific numbers are reporting latencies local to the node. So a write/read that has reached the correct replica and just needs to hit memory/disk.
The non column family specific numbers are reporting latencies from the coordinator. So the latency from the time the coordinator receives a write/read request, contacts the right replica(s), receives an internal response and responds to the client. On Wed, Jul 10, 2013 at 12:27 PM, Christopher Wirt <chris.w...@struq.com>wrote: > I was wondering if anyone knows the difference between the JMX latency > stats and could enlighten me.**** > > ** ** > > We’ve been looking the column family specific stats and see really lovely > < 3ms 99th percentile stats for all our families.**** > > > org.apache.cassandra.metrics:type=ColumnFamily,keyspace=mykeyspace,scope=mycolumnfamily,name=ReadLatency > **** > > ** ** > > Now, when we look at the overall client request read latency stats we see > a far more inconsistent jagged 99th percentile flying between 5ms – 80ms * > *** > > org.apache.cassandra.metrics:type=ClientRequest,scope=Read,name=Latency*** > * > > ** ** > > ** ** > > Thanks**** > > ** ** > > Chris**** > > ** ** > > ** ** > > ** ** > > ** ** >
