Hi all,
I'm trying to understand Tomcat memory usage as observed with
jconsole. I'm using Tomcat 6.0.18 on Mac OS X 10.5.8;
Tomcat is downloaded from the Apache site. I'm starting it with /no/
web applications
at all: just an empty webapps folder, and I'm not hitting it with any
browser.
jconsole shows the following behavior:
Shortly after startup with the heap at 15MB, a GC drops the heap to
just above 5MB.
Over 5 minutes, the heap grows to about 21 MB, at which time another
GC occurs, and it drops to about 6MB.
Over the second 5 minute interval, it rose to a little over 22MB, and
then dropped to just under 5MB.
Then it settles into consistent 5 minute intervals, rising from about
4.8MB to 21.5 MB, then a GC.
So I have three questions:
1) Is this normal Tomcat behavior? Since this is a vanilla Tomcat
download, I assume the answer is yes, but maybe not?
2) What Tomcat activity is consuming the heap?
3) Presumably this means that in planning for a memory restricted
Tomcat + apps, one needs to apportion about 22MB to the Tomcat heap,
apart from heap allocated to applications.
BTW, I verified Chuck's statement that top is bad tool for looking at
Tomcat's heap: at the first pea k rising from 5MB to 21MB, GC dropped
the heap value in jconsole to 6MB, but the RSIZE in top jumped from
54M to 57M.
Thanks in advance,
Ken
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org
For additional commands, e-mail: users-h...@tomcat.apache.org
