The properties of a Sampler component determine which properties of which services are to be sampled, how often they should be sampled, and to whom the samples should be sent. You can use the following properties to configure a Sampler:

sampleSources

The list of services and properties to be sampled. Each element of the list is of the form <service name>.<property name>. For example:

sampleSources=\
     /atg/dynamo/server/HttpServer.handledRequestCount,\
     /atg/dynamo/server/HttpServer.averageRequestHandlingTime,\
     /atg/dynamo/server/HttpServer.activeHandlerCount

The order of the Samples in the SampleEvent matches the order of the properties declared in sampleSources.

scheduler

If you want the Sampler to perform sampling automatically, set this property to point to the Scheduler that schedules the samples:

scheduler=/atg/dynamo/service/Scheduler

schedule

If you want the Sampler to perform sampling automatically, set this property to specify the schedule used to run the samples:

schedule=every 10 seconds

sampleListeners

The list of the SampleListener objects that receive the Samples broadcast by the Sampler:

sampleListeners=\
        MemorySampler,\
        SampleGrapher

Oracle ATG Web Commerce comes with a Sampler component at /atg/dynamo/service/Sampler. It monitors various aspects of the Oracle ATG Web Commerce HTTP server, including throughput, latency, and simultaneous connections. It is configured as follows:

$class=atg.service.statistics.Sampler
scheduler=Scheduler
schedule=every 60 sec
sampleSources=\
        ../../../VMSystem.freeMemory,\
        ../servlet/sessiontracking/SessionManager.residentSessionCount,\
        ../servlet/sessiontracking/SessionManager.createdSessionCount,\
        ../servlet/pipeline/DynamoHandler.handledRequestCount,\
        ../servlet/pipeline/DynamoHandler.averageRequestHandlingTime,\
        ../servlet/pipeline/DynamoHandler.totalRequestHandlingTime,\
        ../server/DrpServer.activeHandlerCount,\
        ../server/HttpServer.activeHandlerCount

sampleListeners=\
        LogSampler

You can modify this component’s configuration, or define your own Sampler component.