In my scene I have a large number of splines (about 500), of wich a lot need to be redrawn - I replaced the original with another one, as PCG doesn’t recognize them as the new ones: The old one is deleted and I redraw a replacement.
Now it can take AGES if I delete a spline, or multiple. The editor becomes not responsive, CPU usage is minimal, memory usage in- and decreases minimal,. but the pagefiles are heavily accessed for reading. It seems the system is paging in constantly, nothing or hardly anything written: Page faults are maxed out, and the editor can run that way for tens of minutes. Killing the editor process - though deleted on screen - runs in the background reading the pagefiles, I presume to clean the paged memory pages, before it is terminated - but much faster than when stopped normally (a few minutes in stead of tens).
After restart I took a somewhat different approach: removed the spline mesh and deleted two splines one by one. The first one took over 10 minutes with the said activity, the second was almost instantly. Even without changing the spline mesh to default (None), so it s the first deletion that tahes ages.