No, not known problems... perhaps you can come up with a short reproducing script?

I tried to localize in which part of the script the problem could in trying
memory_get_usage() which helped me not. The real usage was constant, while i got negative values for emalloc after a few iterations which didn't make any sense to me. This is true with xdebug enabled and also if it's disabled.

Can you give me a hint how I could try to localize this problem? I could sent you the scripts, but I'm sorry, I can not send you the data stored in MySQL since it's sensitive (data for a study which tested about 12.000 pupils of my state.). But if you tell me how can I help assist you in tracking this down I will gladly help.

i also have problem with high memory usage by apache (1-2Gb of ram) while debuging.
i use eclipse for debug and strange thing that it happens only with phpeclipse plugin (pdt+xdebug works fine). if i kill eclipse and java at all memory continues to grow until hang my system or stopping apache. so i think it's not phpeclipse bug but xdebug's one.

php code with which i experience this problem is quite complex. so i can't make testcase example. only i can say recusrion gettes setters autoloading of classes and some other things.

Duplicate of 0000425, which I've just fixed.