When I tuned a news application I found that all the news_items_* views
retrieve the news content blob. Creating a second view
news_items_approved_sans_body and pointing the news queries in question to it,
made those queries lighter (maybe 50%).
So you need to be careful when retrieving "useless" values or perform
"useless" where clauses (in Oracle at least). There's a lot of code in OpenACS
that could and needs to reviewed in this respect.