КАК РЕШИТЬ ЭТУ ЗАДАЧУ?????

Создаётся больная нагрузка на сервере и сайтом дублируются запросы вида.
mysql> show processlist;
+-----+---------+-----------+------+---------+------+----------------------+------------------------------------------------------------------------------------------------------+
| Id | User | Host | db | Command | Time | State | Info |
+-----+---------+-----------+------+---------+------+----------------------+------------------------------------------------------------------------------------------------------+
| 12 | dizuser | localhost | diz | Query | 599 | Copying to tmp table | SELECT c.*,
IFNULL(u.nickname, 0) as nickname,
IFNULL(u.login, 0) as login,
|
| 149 | dizuser | localhost | diz | Query | 395 | Copying to tmp table | SELECT c.*,
IFNULL(u.nickname, 0) as nickname,
IFNULL(u.login, 0) as login,
|
| 150 | dizuser | localhost | diz | Query | 557 | Copying to tmp table | SELECT c.*,
IFNULL(u.nickname, 0) as nickname,
IFNULL(u.login, 0) as login,
|
| 151 | dizuser | localhost | diz | Query | 358 | Copying to tmp table | SELECT c.*,
IFNULL(u.nickname, 0) as nickname,
IFNULL(u.login, 0) as login,
|
| 172 | dizuser | localhost | diz | Query | 420 | Copying to tmp table | SELECT c.*,
IFNULL(u.nickname, 0) as nickname,
IFNULL(u.login, 0) as login,
|
| 173 | dizuser | localhost | diz | Query | 90 | Copying to tmp table | SELECT c.*,
IFNULL(u.nickname, 0) as nickname,
IFNULL(u.login, 0) as login,
|
| 180 | dizuser | localhost | diz | Query | 284 | Copying to tmp table | SELECT c.*,
IFNULL(u.nickname, 0) as nickname,
IFNULL(u.login, 0) as login,
| 183 | dizuser | localhost | diz | Query | 275 | Copying to tmp table | SELECT c.*,
IFNULL(u.nickname, 0) as nickname,
IFNULL(u.login, 0) as login,
|
| 187 | dizuser | localhost | diz | Query | 245 | Copying to tmp table | SELECT c.*,
IFNULL(u.nickname, 0) as nickname,
IFNULL(u.login, 0) as login,
|
| 190 | dizuser | localhost | diz | Query | 230 | Copying to tmp table | SELECT c.*,
IFNULL(u.nickname, 0) as nickname,
IFNULL(u.login, 0) as login,
|
| 192 | dizuser | localhost | diz | Query | 224 | Copying to tmp table | SELECT c.*,
IFNULL(u.nickname, 0) as nickname,
IFNULL(u.login, 0) as login,
|
| 193 | dizuser | localhost | diz | Query | 90 | Copying to tmp table | SELECT c.*,
IFNULL(u.nickname, 0) as nickname,
IFNULL(u.login, 0) as login,
|
| 202 | dizuser | localhost | diz | Query | 77 | Copying to tmp table | SELECT p.*,
u.nickname as author, u.login, u.is_deleted,
|
| 206 | dizuser | localhost | diz | Query | 31 | Copying to tmp table | SELECT c.*,
IFNULL(u.nickname, 0) as nickname,
IFNULL(u.login, 0) as login,
|
| 209 | root | localhost | NULL | Query | 0 | NULL | show processlist |
+-----+---------+-----------+------+---------+------+----------------------+------------------------------------------------------------------------------------------------------+
15 rows in set (0.00 sec)

Как найти и убрать эти дублирующие запросы?