On 4/7/10 12:16 PM, Mark Jones wrote:
Read Latency: NaN ms.
./trunk/src/java/org/apache/cassandra/tools/NodeCmd.java
"
outs.println("\t\tRead Latency: " + String.format("%01.3f",
cfstore.getRecentReadLatencyMicros() / 1000) + "
"
This call is telling you the (Read|Write|Range)Latency since the last
time it was sampled. The other measure of latency is a value since the
node started, exposed via the JMX interface as
"org.apache.cassandra.service.StorageProxy.Attributes.TotalRangeLatencyMicros".
If you are sure to not restart your node while doing your testing, this
should provide you with the latency number you are looking for.
http://wiki.apache.org/cassandra/JmxInterface#org.apache.cassandra.service.StorageProxy.Attributes.TotalRangeLatencyMicros
The JmxInterface wiki page is currently missing a section on the per-CF
attributes, but as cfstats shows, they are available via the JMX
interface as well.
=Rob
