I tried an other approach: I loop with getVersionHistory() which gives me
oldid, date and size which I need, and call getOldVersion() for each oldid.
The sad experience is that the script becomes extremely slow. As the page
under investigation is usually quite big (it's a long talk page) and the
loop is so slow, I got the idea that there might be a memory problem with
the first version.
Is it a possible behaviour of Python 2.7.2 that instead of explicitely
throwing a memory error it just breaks from the loop without notice?