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Using Zing GC Log Analyzer

The Garbage Collector Log Analyzer (GC Log Analyzer) is a tool to view and interpret Java heap, pause time, and operating system metrics gathered while running the ZVM.

The GC Log Analyzer offers significantly reduced memory usage and faster loading of large Garbage Collector log files. In addition, it offers graphs to give an insight into the JIT compilation activity, which is recorded in the gc.log file since ZVM

The GC Log Analyzer runs with JRE (version 7 or older) or JDK (version 7 or older) on any platform, Zing is not required to run it.

GCLogAnalyzer2.jar is self-contained and has no external dependencies.

Download New GC Log Analyzer

Download the latest version of the GC Log Analyzer at

Run GC Log Analyzer

No installation is required to start the GC Log Analyzer. You can start the GC Log Analyzer either directly from the /etc directory of the Zing installation or copy it from the Zing installation directory to your desktop system.

To run the GC Log Analyzer, use the following command:

java -Xmx4g -jar GCLogAnalyzer2.jar gc.log

To run GC Log Analyzer in a non-GUI mode and create an HTML output, use the following as an example:

java -jar GCLogAnalyzer2.jar --generate-html ./output-html ./gc.log

This generates ./output-html/all-graphs.html .

If you need a batch of json files with data from your <logfile>, use:

java -jar GCLogAnalyzer2.jar [--generate-html <dir> [--resize WxH]] [--dump-raw-data <dir>] gc.log

Starting with ZVM the SYSINFO line in the GC log is enhanced to include information about cgroup limits and usage, where applicable.

GC Log Analyzer Command-Line Options

To display the list of command-line options available in the new GC Log Analyzer (for example, for batch usage), run:

java -jar GCLogAnalyzer2.jar --help

Usage Recommendations

  • For big log files, consider increasing the size of the Java heap twice as much as the log file size.

    For example, if you have a 3 GB file, use -Xmx6g to start the GC Log Analyzer.

  • To open gc.log directly from the command line, run:

    java -jar GCLogAnalyzer2.jar gc.log

See Also

Working with Graphs

Understanding a Garbage Collection Log Format

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