Tracing and logging configuration
Configure tracing and logging settings to help diagnose problems or evaluate system performance.
We can configure the application server to start in a trace-enabled state by setting the appropriate configuration properties. We can only enable trace for an application client or standalone process at process startup.
In WebSphere Application Server, V6 and later, a logging infrastructure, extending Java Logging, is used. This results in the following changes to the configuration of the logging infrastructure in WebSphere Application Server:
- Loggers defined in Java logging are equivalent to, and configured in the same way as, trace components introduced in previous versions of WebSphere Application Server. Both are referred to as "components."
- Both Java logging levels and WAS levels can be
used. The following is a complete list of valid levels, ordered in ascending
order of severity:
- all
- finest or debug
- finer or entryExit
- fine or event
- detail
- config
- info
- audit
- warning
- severe or error
- fatal
- off
- Setting the logging and tracing level for a component to all will enable all the logging for that component. Setting the logging and tracing level for a component to off will disable all the logging for that component.
- We can only configure a component to one level. However, configuring a component to a certain level enables it to perform logging on the configured level and any higher severity level.
- Several levels have equivalent names: finest is equivalent to debug; finer is equivalent to entryExit; fine is equivalent to event; severe is equivalent to error.
Java Logging does not distinguish between tracing and message logging. However, previous versions of WAS have made a clear distinction between those kind of messages. In WebSphere Application Server, V6 and later, the differences between tracing and message logging are as follows:
- Tracing messages are messages with lower severity (for example, tracing messages are logged on levels fine, finer, finest, debug, entryExit, or event).
- Tracing messages are generally not localized.
- When tracing is enabled, a much higher volume of messages will be produced.
- Tracing messages provide information for problem determination.
Trace and logging strings
In WebSphere Application Server, V5.1.1 and earlier, trace strings were used for configuring tracing only. Starting in WebSphere Application Server, V6 and later, the "trace string" becomes a "logging string"; it is used to configure both tracing and message logging.
In WebSphere Application Server, V5.1.1 and earlier, the trace service for all WAS components is disabled by default. To request a change to the current state of the trace service, a trace string is passed to the trace service. This trace string encodes the information detailing which level of trace to enable or disable and for which components.
In all versions of WebSphere Application Server, the tracing for all components is disabled by default. To change to the current state of the tracing and message logging, a logging string must be constructed and passed to the server. This logging string specifies what level of trace or logging to enable or disable for specific components.
We can type in trace strings (or logging strings), or construct them using the administrative console. Trace and logging strings must conform to a specific grammar.
For WebSphere Application Server, V5.1.1 and earlier, the specification of this grammar is as follows
TRACESTRING=COMPONENT_TRACE_STRING[:COMPONENT_TRACE_STRING]* COMPONENT_TRACE_STRING=COMPONENT_NAME=LEVEL=STATE[,LEVEL=STATE]* LEVEL = all | entryExit | debug | event STATE = enabled | disabled COMPONENT_NAME = COMPONENT | GROUP
For WebSphere Application Server, V6 and later, the previous grammar is supported. However a new grammar has been added to better represent the underlying infrastructure
LOGGINGSTRING=COMPONENT_LOGGING_STRING[:COMPONENT_LOGGING_STRING]* COMPONENT_TRACE_STRING=COMPONENT_NAME=LEVEL LEVEL = all | (finest | debug) | (finer | entryExit) | (fine | event ) | detail | config | info | audit | warning | (severe | error) | fatal | off COMPONENT_NAME = COMPONENT | GROUP
The COMPONENT_NAME is the name of a component or group registered with the trace service logging infrastructure. Typically, WebSphere Application Server components register using a fully qualified Java class name, for example com.ibm.servlet.engine.ServletEngine. In addition, use a wildcard character of asterisk (*) to terminate a component name and indicate multiple classes or packages. For example, use a component name of com.ibm.servlet.* to specify all components whose names begin with com.ibm.servlet. Use a wildcard character of asterisk (*) at the end of the component or group name to make the logging string applicable to all components or groups whose names start with specified string. For example, a logging string specifying "com.ibm.servlet.*" as a component name will be applied to all components whose names begin with com.ibm.servlet. When an asterisk (*) is used by itself in place of the component name, the level the string specifies, will be applied to all components.
The following are examples of using an asterisk (*) in logging strings. Note that the asterisk (*) in the logging string does not need to have a period (.) in front of it. The period (.) can be used anywhere in the logging string.
- com.ibm.ejs.ras.*=all - enables tracing for all loggers with names starting with "com.ibm.ejs.ras.". If there is a logger named "com.ibm.ejs.ras" it will not have trace enabled.
- com.ibm.ejs.ras*=all - enables tracing for all loggers with names starting with "com.ibm.ejs.ras", such as com.ibm.ejs.ras, com.ibm.ejs.raslogger, com.ibm.ejs.ras.ManagerAdmin
Note:
- In WebSphere Application Server, V5.1.1 and earlier, you could set the level to "all=disabled" to disable tracing. This syntax, beginning with Version 6.0, will result in LEVEL=info; tracing will be disabled, but logging will be enabled.
- In WebSphere Application Server, V6 and later, "info" is the default level. If the specified component is not present (*=xxx is not found), *=info is always implied. Any component that is not matched by the trace string will have its level set to info.
- If the logging string does not start with a component logging string specifying a level for all components, using the "*" in place of component name, one will be added, setting the default level for all components.
- STATE = enabled | disabled is not needed in V6 and later. However,
if used, it has the following effect:
- "enabled" sets the logging for the component specified to the level specified
- "disabled" sets the logging for the component specified to one level above
the level specified. The following examples illustrate the effect that disabling
has on the logging level:
Logging string Resulting logging level Notes com.ibm.ejs.ras=debug=disabled com.ibm.ejs.ras=finer debug (version 5) = finest (version 6) com.ibm.ejs.ras=all=disabled com.ibm.ejs.ras=info "all=disabled" will disable tracing; logging is still enabled. com.ibm.ejs.ras=fatal=disabled com.ibm.ejs.ras=off com.ibm.ejs.ras=off=disabled com.ibm.ejs.ras=off off is the highest severity
Proceed from broad to specific trace specifications in the trace string
Best practice: Start
the trace string from the most broad component groups and then select more
specific traces. The advantage to this approach is that the trace settings
for classes or packages that are contained in a larger group will be specified
correctly by including them later in the trace string.bprac
The logging string is processed from left to right. During the processing, part of the logging string might be modified or removed if the levels they configure are being overridden by another part of the logging string.
Groups that contain packages that disable traces will disable any packages that were enabled previously on the same line. For example
This indicates that the only tracing should come from MyGroup1, MyGroup2, and com.mycompany.mypackage.* (with more specific tracing for MyClass). If you reversed this string, all tracing would be disabled.*=off : MyGroup1=info : MyGroup2=finest : com.mycompany.mypackage.*=info : com.mycompany.mypackage.MyClass=finest
Examples
Examples of legal trace strings include:
V5 syntax V6 syntax
Related tasks
Enabling trace on client and standalone applications Enabling trace at server startup Enabling trace on a running server Manage the application server trace service