JVM status

[Eag. E]

Hi Gurus,

Could I get some knowledge from you about the heap size (query service)
See my attach of screenshot.

1. Committed heap size (bytes)
2. Current heap size (bytes)
3. Initially requested heap size (bytes)   
4. Maximum heap size (bytes)

I am not sure what is the difference between 1 & 2.
What's more, I set 3 as 8GB, it seems that when I start Cognos --> running report, the 3 is still in a low level (less then 4GB), then start keep growing. Is that expected? Because I thought it should be 8GB when queryservice started, no?

Thanks

Eag