The batch edit plugin performs global find and replace operations on all pages of a given namespace. It does so really well.
However, after changing a few hundred pages, it will not find the search pattern at all. That is, I preview and apply the pattern successfully for a few times, and then it might find the pattern in just one file in a namespace when there are many more files which are certain to contain the pattern.
It seems that after waiting a longish while (an hour), it might find more pages with the pattern, but by no means all. It also seems that restarting the server may recover the function. It did so once, it didn't do so another time.
How do I find the cause for this problem? - I am a mere user and do not really know how to handle Apache and PHP.