The biggest single thing we keep in hot RAM is the interconnect table used for the 'related' page. We keep it in memory because we want to be able to give the related list while the person who asked for it is still young enough to care about the answer. Even adding something like one 32-bit timestamp would add another 24M of ram use. We're maxed out and running at 100% of 64GB ram now. Adding 24M would mean we'd have something page out, impacting performance.
The next step for us DB-wise will be to go to a No SQL or similar setup to relieve this kind of limitation. This means more hardware. Cheaper hardware, but more of it. This is one of the reasons we're trying new advertisers, so we can budget-up for the growth we need.
Goal: Clear, Concise and Witty
An improvement to the code storing the relationships has been made that will relieve a big chunk of this issue. I'll close this one out so any new issues will be easier to spot.
Goal: Clear, Concise and Witty
Might it be possible to make a way "watch" not only a trope page, but also a the wicks of a trope, so that you get notices whenever a trope is added to a page on the wiki. The reason being is that many of us are monitoring certain trope pages to prevent misuse, however there is no easy way to monitor how the trope is being used on other pages, especially if it is a trope with hundreds of wicks, making it hard to figure out which ones are new when you look at the "Related To" page.