Francisco Eduardo Webber writes:

the memory usage of the python threads grows slowly but constantly until= =20 zope dies .... I do no longer remember when the "SQL-Alias" memory leak has been fixed (---> searchable mailing list archives). I think it was after 2.3.0.

Maybe this leak causes your problems. If not, do you know the debug section in Zope's control panel. If the problem comes from an Python application fault (rather than C extensions), then the reference counts there may give you a hint. Dieter