bug 861153 on SourceForge
about this. Tentative conclusion there is that this is probably due
to the previously discussed massive memory leaks in certain versions
of Oracle's OCI client libraries. If so, then this problem has
nothing to do with OpenACS or AOLserver per-se, it is Oracle's bug.
Best solution is to either patch or upgrade Oracle's client libraries,
but if that's not feasible, it might also be possible to work around
the issue by changing the AOLserver Oracle driver to use different OCI
calls which may trigger fewer memory leaks.