19.3. Defining Metrics Collection

The monitoring baselines have two configuration properties that define how the automatic metric baselines are calculated. These properties don't set the value; they set the window of time used for the baseline averages.

Metrics are collected at the intervals specified by the collection schedule. Because not all metrics are mission critical or even likely to change, JBoss ON has different collection schedules for different metrics, with critical metrics collected more frequently.

For most environments, setting a daily collection schedule (once every 24 hours) is sufficient.

To change the collection interval for a specific metric:

The metrics which are collected for a resource type are defined in the monitoring template for the resource type. Each resource type has some metrics disabled by default, and these must be manually enabled. Likewise, metrics which are enabled by default can be disabled.

A SQL query can be added to a PostgreSQL database as a child resource. That entry becomes a custom metric for that PostgreSQL database.

A query metric must have two columns that allow the JBoss ON agent to collect data for the query:

The query has to return a single row with those two columns. The first column signals that it is a collected metric, and the second gives the count for the metric.

For example, to track logged-in users:

SELECT 'metricColumn', count(id) FROM my_application_user WHERE is_logged_in = true

SELECT 'metricColumn', count(id) FROM my_application_user WHERE is_logged_in = true

The SELECT statement defines the metric for the JBoss ON agent. The rest of the query collects the data from the database. Simple as that.

To add a metric based on a query:

Once the query is created, then the agent begins collecting the counts for the data.