[kepler-dev] Memory leak.

[Kevin Ruland]

Hi guys,

As everybody else, I was concerned that Kepler's memory consumption, so 
I ran just kepler startup through -Xrunhprof and looked at the 250M 
memory report.  I terminated the application "normally" by closing the 
main window as soon as it appeared.

The answer is... Kepler  is leaking.  Yes, in java you don't have memory 
leaks you have "in advertant reference retention".

The allocation which is not released is 
com.microstar.xml.XmlParser.pushURL(XmlParser.java:3169).   This is 
accounting for 333 leaked char[] totalling 10,919,736 bytes.  This is 
15% of the allocated memory when I terminated the application.  The 
number 333 is really interesting it happens to be exactly the same as 
the number of kar files/actors in the current kepler.  I suspect 
ActorMetadata or some such is hanging onto a moml parser.

Also, there are 333 byte[] totalling 5,461,200 bytes.  Also in 
XmlParser.java:4182.  All told about 20% of leaked memory is accounted 
for by XmlParser.

I tracked this reference retention down to the ptolemy.moml.MoMLParser 
class.  It has a private member call _parser which is an XmlParser.  
However, it is not released after parsing is finished.   I added a 
'_parser = null' at line 1326, right before the return in parse( URL, 
Reader ).  That definitely plugged it, but I am uncertain the fix is 
completely safe.  I'm afraid I'll have to defer to The One True Ptolemy 
Hackers.

There are still a couple of very large allocations but they might be 
understandable.  The largest 5 allocations account for 8.5M, 17% of 
memory allocated.  This still seems large since there had been no 
workflow created.  I might be able to find some time to look into these 
tomorrow.

Kevin