Just a report & workaround fyi for anyone running into the same problem: I created a db consisting of a single, fairly small table (4 fields of short strings & a few floats) and imported a large amount of data into it (over a million records). Added a few indexes. The db size is about 440MB. Upon trying to access the data, my sql methods puked - got some memory errors sometimes, sometimes there was something wrong with a "query" variable or something. I did not dig deep on those. Alas, upgrade to Zope 2.7.8 seems to have solved the problem. And there was much joy. Cheers, Petri