Monitoring Java heap usage on a Weblogic Server - monitoring

Question

I am monitoring Java heap usage on all managed servers in the Weblogic 10.3 domain using WLST. I have written a Jython script to achieve this. This script first logs into the admin server in the domain. Following is the code snippet that fetches the heap statistics for each managed server:
def getServerJavaHeap():
domainRuntime()
servers=domainRuntimeService.getServerRuntimes()
for server in servers:
free = int(server.getJVMRuntime().getHeapFreeCurrent())/(1024*1024)
freePct = int(server.getJVMRuntime().getHeapFreePercent())
current = int(server.getJVMRuntime().getHeapSizeCurrent())/(1024*1024)
max = int(server.getJVMRuntime().getHeapSizeMax())/(1024*1024)
print 'Domain Name #', cmo.getName()
print 'Server Name #', server.getName()
print 'Current Heap Size #', current
print 'Current Heap Free #', free
print 'Maximum Heap Size #', max
print 'Percentage Heap Free #', freePct
The heap statistics that the above code fetches is different from what the Weblogic admin console shows. For instance for managed server123
The above code gives the heap size usage as 1.25GB while the admin console shows heap usages as 3GB
I am wondering why is there a discrepancy in what admin console shows and the output of the above code. I am trying to determine if I am looking in the right place and invoking the right method calls (listed here in the docs) to get the heap statistics on each managed server.
I am sure the time when the script ran also is a factor. Was wondering how frequently the admin console refreshes these tables.

Answer 1

I can't see anything wrong with your approach tbh. The admin console page won't update automatically unless you click on the auto-refresh icon (the two arrows forming a circle) in the top left of the table. By default the refresh interval is 10 seconds but this can be set from the 'Preferences' page - the link is on the banner of every page.
I tried on both an Admin server and a managed server and as long as I ran the code close to a refresh, the numbers tied up. I can only assume a garbage collect run between the time the console displayed the data and your script ran.