DB QUERY ERROR (one_row_query()): Out of resources when opening file './mbscientific_2017/pages.MYD' (Errcode: 24 - Too many open files)

SELECT seo_title, seo_keywords, seo_description FROM pages WHERE CHAR_LENGTH(seo_title) AND pageid = (SELECT item_id FROM rewrite WHERE groupid = 2 AND module_id = 4 AND rewrite = 'policyandaction' LIMIT 1)