DB QUERY ERROR (one_row_query()): Out of resources when opening file './mandarinab_2016/pages_categories.MYD' (Errcode: 24 - Too many open files)

SELECT seo_title, seo_keywords, seo_description FROM pages AS p INNER JOIN pages_categories AS c ON c.categoryid = p.categoryid WHERE c.groupid = 2 AND p.special_page = 'start' LIMIT 1;