no minor GC

Discussion in 'Java' started by gmh, May 16, 2007.

  1. gmh

    gmh Guest

    I have a web-based Java application running under Tomcat 5.0.16,
    started with the following JVM options:

    -Xms128m
    -Xmx2304m
    -Dcom.sun.management.jmxremote
    -Dcom.sun.management.jmxremote.port=<port>
    -Dcom.sun.management.jmxremote.ssl=false
    -Dcom.sun.management.jmxremote.authenticate=false
    -Djava.awt.headless=true
    -Dsun.net.client.defaultReadTimeout=600000
    -Dsun.net.client.defaultConnectTimeout=120000
    -XX:+HeapDumpOnOutOfMemoryError
    -Djavax.net.ssl.trustStoreType=PKCS12
    -Djavax.net.ssl.trustStore=/opt/validation/xxxx.xxx
    -Djavax.net.ssl.trustStorePassword=xxxxxx
    -Xloggc:/home/gmh2441/gc.dat
    -d64
    -server

    (my JVM version is 1.5.0_11 (64 bit))

    In monitoring the application, both with jconsole (from JDK 1.5) and
    looking at the garbage collection log, I have seen that after several
    days of usage, there are no longer any minor GCs taking place; it
    appears, from the jconsole graph, that objects go straight from Eden
    space to tenured space, and the GC takes place there. I see this in
    the GC log as after those several days, there are no minor GCs listed
    in my log, only full GCs. As far as I know, there are no explicit
    calls to System.gc() in the application. I know that using RMI causes
    a full GC every minute by default, but I'm seeing too many full GCs
    for this to be the case. What does this lack of minor GCs indicate?

    Thanks!

    Lynn.
     
    gmh, May 16, 2007
    #1
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  2. Maybe your sessions do not expire and they hold on to too much data.
    Just a wild guess.

    robert
     
    Robert Klemme, May 16, 2007
    #2
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