Java GC log analysis

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

Ref: Java Garbage Collection Log messages

A picture can tell a thousand words. It will be a lot easier to interpret your GC logs visually. I've found GCViewer very useful in the past, including its references to related topics.

An excellent whitepaper on memory management in HotSpot JVM will answer most of the questions you might have on the topic.

I would use a graphical tool to analyze the file. It's difficult to extract conclusions from raw data. See Know of any garbage collection log analysis tools?