[PyKDE] Constantly increasing memory usage in (some) PyQt applications

[Umit Oztosun]

Hello,

I've been using PyQt for about six months. IMHO, PyQt is *great*, a perfect 
tool for creating first-class portable GUI applications. It is also very 
enjoyable to work with Python and Qt, both are elegant and nicely designed.

However, I've some issues about the memory usage of PyQt applications, both 
the ones that I wrote and that I use. As an example I've examined the memory 
usage of Eric with K System Guard:

                      VmSize    VmRss
Initial                49056    35168
Open Settings Window   51116    37884
Close & Open Again     52564    39440
Close & Open Again     54080    40952
Close & Open Again     55724    42588
Close & Open Again     57280    44088
Close & Open Again     58728    45588

Both VmSize and VmRss values are constantly increasing. For the test, I 
started Eric3, then repeatedly clicked Settings -> Preferences and close 
preferences dialog.

I observe similar memory usage patterns on my own code. As the complexity of 
my dialogs/widgets increase, I see more of incresing memory usage.

I tried to track down possible leakages on my code by using gc module, 
specially gc.get_objects() in Python level. But I still observe increased 
memory usage even if gc.get_objects() seems to stay constant.

I googled and searched various lists about Python, as far as I understand, 
Python never releases allocated memory back to the OS, and some objects like 
integers and floats are basically immortal. So it is normal to observe an 
"always increasing memory usage" pattern because memory is never released 
back. However, once the objects are garbage collected, released memory is 
available to be used by new objects. So, for a simple situation like opening 
and closing a dialog, I think the memory usage should remain constant at 
*some* point.

Is this behaviour normal? Can it harm long-running GUI processes?

Best regards,
Umit OZTOSUN

System Information:
Intel P4 2.5 GHz, 512 MB RAM
Debian Testing, Python 2.3.4, Qt 3.3.3, PyQt 3.12, SIP 4.0.1, Eric 3.5.0