Speed tradeoff of Java's -Xms and -Xmx options

Question

Given these two commands

A:

$ java -Xms10G -Xmx10G myjavacode input.txt

B:

$ java -Xms5G -Xmx5G myjavacode input.tx         


        

Answer 1

I have found that in some cases too much memory can slow the program down.

For example I had a hibernate based transform engine that started running slowly as the load increased. It turned out that each time we got an object from the db, hibernate was checking memory for objects that would never be used again.

The solution was to evict the old objects from the session.

Stuart