Fixing broken “screen options” in wordpress site

SELECT * from wp_usermeta where `meta_key` like 'edit_%_per_page'

So probably you chose “Number of items per page” as 1000 or 200 and now the page doesnt load anymore because your database ran out of memory.

If that is the case, run the above query on phpmysql or any other way, edit the numbers and fixed!