mysql> explain SELECT  partner_name, partner_url, partner_description FROM lb_link LEFT JOIN lb_partner ON link_partner_id = partner_id WHERE link_site_id = 142 AND partner_category = '2' AND partner_language = 'jp' AND link_status IN (1,2)   LIMIT 4600, 40\G;
*************************** 1. row ***************************
           id: 1
  select_type: SIMPLE
        table: lb_partner
         type: ref
possible_keys: PRIMARY,partner_language,p_cat_lang
          key: p_cat_lang
      key_len: 10
          ref: const,const
         rows: 5408
        Extra: Using where
*************************** 2. row ***************************
           id: 1
  select_type: SIMPLE
        table: lb_link
         type: eq_ref
possible_keys: link_partner_id
          key: link_partner_id
      key_len: 8
          ref: const,link_builder.lb_partner.partner_id
         rows: 1
        Extra: Using where
2 rows in set (0.00 sec)