Error in SQL query '( SELECT id, added, published, modified, domain, title, description, alexa_rank, estimated_daily_visits, estimated_daily_revenue, estimated_worth FROM `sites` USE INDEX(id_state_adult) WHERE id < 1940521 AND state='published' AND adult='0' ORDER BY id DESC LIMIT 5 ) UNION ( SELECT id, added, published, modified, domain, title, description, alexa_rank, estimated_daily_visits, estimated_daily_revenue, estimated_worth FROM `sites` USE INDEX(id_state_adult) WHERE id > 1940521 AND state='published' AND adult='0' ORDER BY id ASC LIMIT 5 ) ORDER BY id DESC': Got error 28 from storage engine