Using the Built-in Diagnostic System Modules

3 Using the Built-in Diagnostic System Modules

The built-in diagnostic system modules are provided by the WebLogic Diagnostics Framework (WLDF) as a simple and easy-to-use mechanism for performing basic health and performance monitoring of a WebLogic Server instance.

Overview
The WLDF built-in diagnostic modules collect data from key WebLogic Server run-time MBeans that monitor the main components of a server instance.

Overview

The WLDF built-in diagnostic modules collect data from key WebLogic Server run-time MBeans that monitor the main components of a server instance.Those main components are:

JVM
WebLogic Server run time
JDBC, JMS, transaction, and logging services
Jakarta EE containers hosting servlets, EJBs, and Connector Architecture resource adapters

When configured in a WebLogic Server instance, the built-in diagnostic modules are particularly useful for providing a low-overhead, historical record of server performance. As server workload changes over time, or the performance characteristics change as a result of updates made to the server's configuration, you can examine the data collected by the built-ins to obtain details about performance changes. For example, if you notice a slowdown in the response time of one or more deployed applications, you can use the Monitoring Dashboard or the Metrics Log table in the WebLogic Remote Console to examine the data collected by the built-ins for performance bottlenecks associated with one or more WebLogic Server subsystems. Then using other diagnostic tools, such as custom diagnostic modules, policies and actions, or Java Flight Recorder, you can drill down further into details about those bottlenecks to pinpoint specific causes and test the effectiveness of solutions.

In WebLogic domains configured to run in production mode, a built-in diagnostic module is enabled by default in each server instance. (In domains configured to run in development mode, built-ins are disabled by default.) However, a built-in diagnostic module can be enabled or disabled for a server instance easily and dynamically, using either the WebLogic Remote Console or WLST.

Data collected by the built-in diagnostic modules can be accessed easily, using tools such as the Metrics Log table in the WebLogic Remote Console or the Monitoring Dashboard. The data can also be accessed programmatically using JMX, WLST, or REST.

Parent topic: Using the Built-in Diagnostic System Modules

Types of Built-in Diagnostic System Modules

WLDF provides three built-in diagnostic system module types:

Low — Captures the most important data from key WebLogic Server runtime MBeans (enabled by default in production mode).
Medium — Captures additional attributes from the WebLogic Server runtime MBeans captured by Low, and also includes data from additional runtime MBeans.
High — Captures the most verbose data from attributes on the WebLogic Server runtime MBeans captured by Medium, and also includes data from a larger number of runtime MBeans.

The built-in diagnostic system module type configured for a server instance is specified in the WLDFServerDiagnosticMBean.WLDFBuiltinSystemResourceType=string MBean attribute, where string can be set to one of Low, Medium, High, or None.

Parent topic: Overview

Data Collected by Built-in Diagnostic System Modules

When you enable a built-in diagnostic module in a WebLogic Server instance, WLDF begins collecting data from key WebLogic Server run-time MBeans to obtain information, such as the following:

Data Category	Example of Information Collected
JVM statistics	Amount of available free memory and JVM processor load on host machine.
Thread statistics	Threads being held by a request and the number of pending user requests.
JDBC subsystem statistics	Examples of information collected may include: Number of connections currently in use by applications. Average amount of time taken to create a physical connection to the database. Number of leaked connections (that is, connections reserved from the data source but not returned to the data source). Number of available and idle database connections. Cumulative, running count of requests for a connection from a data source.
JMS subsystem statistics	Examples of information collected may include statistics about: WebLogic JMS consumers and producers, such as number of messages pending by a consumer or producer. JMS destinations, such as current number of messages in the destination, and number of pending messages in the destination. The current number of connections to WebLogic Server.
Logging subsystem statistics	The number of log messages that the WebLogic Server instance has generated.
JTA subsystem	Examples of information collected may include: Number of active transactions on the server. Total number of seconds that transactions were active for all committed transactions.
Jakarta EE container statistics	Examples of information collected may include statistics about: EJBs, such as the EJB cache, EJB pool, and EJB transaction statistics. Servlets, such as the average amount of time all invocations of a servlet have executed since the servlet was created.

Note:

The specific configuration of each built-in diagnostic module is internal to WebLogic Server and subject to change in a future release.

Parent topic: Overview