We already have page_is_redirect_latest in the mediawiki_page_history table, but it would be very useful to have an is_redirect flag for each revision.

This would allow us to analyze article trends—such as deletion rates, average edit rates, or article counts—over time while properly filtering out redirects (which can significantly alter the conclusions). Knowing whether a page is currently a redirect can help with this, but redirects are sometimes turned into regular pages and vice versa. For example, on the English Wikipedia, it's relatively common that a new user creates an article which duplicates an existing one, and a patroller reacts by turning that new page into a redirect to the existing article.