Java GC log analysis

Question

I am new to gc log.

What is the meaning of the following gc log. Does it imply some useful information?

16960.890: [GC [PSYoungGen: 111960K->36400K(523584K)] 845053K->770190K(1286720K), 0.0270419 secs] [Times: user=0.13 sys=0.00, real=0.03 secs] 
16960.917: [Full GC (System) [PSYoungGen: 36400K->0K(523584K)] [PSOldGen: 733789K->714479K(763136K)] 770190K->714479K(1286720K) [PSPermGen: 34154K->34154K(38208K)], 1.0982179 secs] [Times: user=1.09 sys=0.00, real=1.09 secs] 

what does PSYoundGen mean? what does the Full GC line mean? i search it in google ,but does not understand it clearly. thanks for the reply!

Answer 1

Try Online GC Log analyzer , This is based on GC Viewer http://gcloganalyzer.com

Answer 2

PSYoungGen refers to the garbage collector in use for the minor collection. PS stands for Parallel Scavenge.

Ref: Java Garbage Collection Log messages

Answer 3

GC logs are vital artifacts to troubleshoot memory/CPU related problems and optimize applications performance.

Enable java 9 GC Logs

To enable GC logging in Java 9, a new system property has been introduced. You need to pass this system property during application startup:

-Xlog:gc*:file=

Example:

-Xlog:gc*:file=/tmp/logs/gc.log

Tools to analyze

GC log format is completely changed in Java 9. To analyze Java 9 GC logs, it’s highly recommended to use GC log analysis tools like GCeasy, HPJmeter. These tools parse java 9 GC logs and generate great graphical visualizations of the data, reports Key Performance Indicators and several other useful metrics.