4.8 JavaVM GC Log
The JavaVM GC log can be acquired only when the log output destination is set before starting JavaVM or the J2EE server.
The output destination of the GC log is specified in the ejb.server.log.directory parameter in the <configuration> tag of logical J2EE server (j2ee-server), in the Easy Setup definition file.
Also, when you want to perform a Full GC for the running Java processes, execute the javagc command. The javagc command can also be used for measuring the memory used for one transaction, investigating memory leak, and application debugging other than for investigating the cause when a problem occurs.
The execution format of the javagc command when performing a Full GC by specifying a running Java process is as follows. Note that for other options that can be specified, see javagc (forcibly perform GC) in the uCosminexus Application Server Command Reference Guide.
- Execution format
javagc -p process-ID
The following log is output as the execution result. Note that in this example, -XX:+HitachiVerboseGCPrintCause has been specified as the option.
[VGC]<Wed Mar 17 00:42:30 2004>(Skip Full:0,Copy:0)[ Full GC 149K->149K(1984K),0.0786038 secs] [ DefNew::Eden:264K->0K(512K)] [ DefNew::Survivor:0K->63K(64K)] [ Tenured: 85K->149K(1408K)] [Metaspace: 3634K(4492K, 4492K)->3634K(4492K, 4492K)][class space: 356K(388K, 388K)->356K(388K, 388K)] [ cause:JavaGC Command]