[Nepomuk] A nepomuk optimisation amplifying a plasma bug

[Simeon Bird]

Hi,

There is a plasma bug: https://bugs.kde.org/show_bug.cgi?id=313319
which seems to be that plasma is constantly changing the icon in the
list of activities in the activity manager.

Using dbus-monitor I was able to see that it is switching between the
'user-desktop' icon and the '' icon (which I think is the randomly
coloured ball thing you get by default?).

The reason this is about to become a serious problem, rather than an
annoying graphical glitch, is that when the icon changes,
plasma-desktop sends, via dbus, an ActivityIconChanged message to the
ActivityManager, which goes and stores the new icon in nepomuk using
Nepomuk2::Resource.

Previously nepomuk was rather slow at storing the new icon, but I have
some patches ready for submission which make it much faster. This lets
plasma change the icon quite fast, and means that virtuoso will use
all of a CPU switching the icon back and forth endlessly. I don't want
to commit changes that are known to break things, but also making this
bit of nepomuk faster makes kmail faster, so I am loathe to abandon
them. Is there any chance someone who knows how this bit of plasma
works could fix the bug? I couldn't even figure out where the message
was being emitted from, I'm afraid...

Thanks,
Simeon