Foglight for Java EE Technologies 5.9.12 - Installation Guide

Changing the Maximum Number of Methods Tracked

The MaxNumberOfMethodsTracked setting controls the maximum number of Named Methods that the Java EE agent tracks. If the Named Methods list contains a greater number of methods than the value set for MaxNumberOfMethodsTracked, only the first MaxNumberOfMethodsTracked methods are tracked.

For example, if you create a named method list that contains 101 methods, but leave the maximum number of methods tracked set to the default of 100, then only the first 100 methods that are run from the named method list are tracked. The method that is not tracked is the one that runs last.

NOTE: This setting is only valid for Full Detail and Component Detail Instrumentation Levels. Changing this value has no effect if the Instrumentation Level is set to Basic Detail or No Detail. For more information about setting instrumentation levels, see Changing the instrumentation level for Request Metric data collection .

TIP: To review how to access the instrumentation settings editor, see Editing agent instrumentation configurations .

If you manually edit the instrumentation.config file, use the following syntax to specify the maximum number of methods tracked.

Object Tracking settings

The Object Tracking instrumentation settings for a Java EE agent determine how the agent tracks objects that are not reclaimed by the garbage collector. Changing any of these settings can have performance implications. Review the provided information before changing any settings.

Tracking object classes

Use the ObjectTrackerClasses setting to watch for objects that are never reclaimed by the garbage collector. You can specify groups of classes with allocated object instances that are tracked during a sampled request.

Object tracking impacts performance overhead if the number of tracked instances is too high. The simplest way to reduce imposed overhead is to track a smaller number of classes. Recording should be delayed until the application has reached a steady state (that is, after start-up work is complete and permanent objects have been created). Use the IgnoredAllocations setting to indicate which objects should not be tracked, even if those allocations are performed by classes in this tracked class list. For more information, see Ignoring specific objects.

NOTE: The ObjectTrackerClasses settings only take effect when object tracking is enabled. Object Tracking can be enabled and disabled on a per request basis, by setting the Enable Object Tracking option found in the Application Servers Monitor > Server JVM view. For more information, see the Foglight for Application Servers User Guide. The pre-instrumentor script must be run on all agent machines after changing either the ObjectTrackerClasses or IgnoredAllocations properties.

For example, the following procedure shows how to configure this object tracking:

TIP: To review how to access the instrumentation settings editor, see Editing agent instrumentation configurations .

2	To add tracked object classes, click Edit beside ObjectTrackerClasses.

Click Add multiple to define several classes at once.

5	Click Add.

You may also want to ignore specific objects. For more information, see Ignoring specific objects.

If you manually edit the instrumentation.config file, use the following syntax to specify the object tracking instrumentation.

ObjectTrackerClasses = ClassList(
include "com.globex.plan.",
exclude /(\.|^)globex\./

include "com.acme.Widget",

include "java.util.Stack",
include "java.util.Vector",
);

This example tracks all classes in the com.globex.plan package, but it does not track any other classes with globex in the name. It also tracks the com.acme.Widget class, as well as the listed collection classes.

Ignoring specific objects

Even with object tracking enabled, some object allocations may be considered uninteresting. For example, the StringBuffer class is allocated as a temporary object by boilerplate code and is automatically generated by Java compilers. As a result of string manipulation, these objects are generated but should not cause memory issues. Use the IgnoredAllocations property to indicate objects that should not be tracked, even if those allocations are performed by classes in the tracked class list. For more information about tracking object classes, see Tracking object classes .

By default, java.lang.StringBuffer and java.lang.StringBuilder are ignored.

1	On the Object Tracking tab, click Edit beside IgnoredAllocations.

If you manually edit the instrumentation.config file, use the following syntax to specify the ignored allocations.

IgnoredAllocations = ClassList();