Jens Frank wrote: Well... we've already established that this would have to live in a separate table, since it would have to be MyISAM. The table doesn't need to be written to for each edit, only when a category is added/changed/deleted from a page, which must be a pretty small subset of edits (wild guess: 10%?), so maybe it's not that big a problem...? To dig up a little history, the queries I/we have tried on the existing categorylinks table take too long, so we either 1) can't run queries against really big categories or 2) need a separate table/data structure. Aerik