Monitoring JVM Heap

Question

I would like to be able to see what happened to the JVM's heap following a
performance test.
I'm really only interested in amount of heap used (ideally for each area of
the heap - in 1.3 onwards). If I could get this figure regularly (say every
5 seconds) I would be able to plot and see from the graph whether I have too
little or too much heap.
Is verbosegc the best way to do this i.e. just get the figures either side
of a gc? Or is there a better way? I don't want a GUI tool as the runs can
take hours and I want to be able to sleep! Just something that outputs to a
file.
Thanks in advance for all advice
Ed

Answer 1

"Ed Barrett" <[email protected]> wrote:
I would like to be able to see what happened to the JVM's heap following
a
performance test.
I'm really only interested in amount of heap used (ideally for each area
of
the heap - in 1.3 onwards). If I could get this figure regularly (say
every
5 seconds) I would be able to plot and see from the graph whether I have
too
little or too much heap.
Is verbosegc the best way to do this i.e. just get the figures either
side
of a gc? Or is there a better way? I don't want a GUI tool as the runs
can
take hours and I want to be able to sleep! Just something that outputs
to a
file.
Thanks in advance for all advice
Ed
Verbosegc is a good option. Here is how you can do it. Set the heap size to one
of your lower settings. Turn on verbosegc. See how frequently you collect GC.
If you never do it then you do not use a high amount of memory. If the GC is too
frequent then your heap size is small.