Collected Stats

Scheduling Data Collection

Command line properties can be used to configure stats collection schedules. The template of these properties is:

-Dcom.googlecode.psiprobe.beans.stats.collectors.CATEGORY.PARAMETER=EXPRESSION

Category

The category of statistics to configure. Must be one of the following:

Category	Description	Data Points per Collection
`app`	Number of requests/errors, current/average processing time time	4 x (# of apps) + 2
`cluster`	Bytes sent/received, messages sent/received	4
`connector`	Number of requests/errors, bytes sent/received, processing time	5 x (# of connectors)
`datasource`	established/busy connections	2 x (# of datasources)
`memory`	JVM memory used per pool	1 x (# of memory pools) + 1
`runtime`	OS physical/virtual/swap memory used, CPU usage	4

Parameter

The parameter for the specified category. Must be one of the following:

Parameter	Description
`period`	The length of time between each collection
`phase`	The offset from the top of the minute or hour when the collection will take place
`span`	The amount of time each data point is retained in history

Expression

A short time expression consisting of a number and a letter representing the unit of time (s for seconds, m for minutes, or h for hours).

The Expression you choose for a category's period should evenly divide the next highest unit of time. Poor choices include 17s, 24m or 5h. Good choices include 15s, 30m, or 6h.

Examples

You may view the default values here to see examples.

Memory Consumption

Each data point takes up 24 bytes of memory, so these statistics can take up large amounts of memory if you have a short period, a long span, or a large number of items within the category. To determine the amount of memory taken up by a category's data, use the following formula:

$m=\frac{24ds}{p}$ , where

m = Memory used in bytes
d = Data Points per Collection (see Category above)
s = span (in seconds)
p = period (in seconds)

For instance, if you configure the cluster category to collect information every 10 seconds and retain it for 3 days, this will take up 2,488,320 bytes (2.37 MB) of memory. The same settings for app statistics would take up about the same amount of memory per application.

Excluding PSI Probe

PSI Probe can ignore its own requests when calculating cumulative application statistics. Just add the following to the command line:

-Dcom.googlecode.psiprobe.beans.stats.collectors.app.selfIgnored=true