WordPress database error: [Error writing file '/tmp/MYyAWvg0' (Errcode: 28 - No space left on device)]

SELECT SQL_CALC_FOUND_ROWS wwpp_posts.ID FROM wwpp_posts LEFT JOIN wwpp_postmeta ON (wwpp_posts.ID = wwpp_postmeta.post_id AND wwpp_postmeta.meta_key = 'rate' ) LEFT JOIN wwpp_postmeta AS mt1 ON ( wwpp_posts.ID = mt1.post_id ) WHERE 1=1 AND ( wwpp_postmeta.post_id IS NULL OR mt1.meta_key = 'rate' ) AND wwpp_posts.post_type = 'post' AND (wwpp_posts.post_status = 'publish') GROUP BY wwpp_posts.ID ORDER BY wwpp_postmeta.meta_value+0 DESC LIMIT 0, 4