MYSQL分表优化

我们的项目中有好多不等于的情况。今天写这篇文章简单的分析一下怎么个优化法。
这里的分表逻辑是根据t_group表的user_name组的个数来分的。
因为这种情况单独user_name字段上的索引就属于烂索引。起不了啥名明显的效果。
1、试验PROCEDURE.
DELIMITER $$
DROP PROCEDURE `t_girl`.`sp_split_table`$$
CREATE PROCEDURE `t_girl`.`sp_split_table`()
BEGIN
declare done int default 0;
declare v_user_name varchar(20) default '';
declare v_table_name varchar(64) default '';
-- Get all users' name.
declare cur1 cursor for select user_name from t_group group by user_name;
-- Deal with error or warnings.
declare continue handler for 1329 set done = 1;
-- Open cursor.
open cur1;
while done <> 1
do 
    fetch cur1 into v_user_name;
    if not done then
      -- Get table name.
      set v_table_name = concat('t_group_',v_user_name);
      -- Create new extra table.
      set @stmt = concat('create table ',v_table_name,' like t_group');
      prepare s1 from @stmt;
      execute s1;
      drop prepare s1;
      -- Load data into it.
      set @stmt = concat('insert into ',v_table_name,' select * from t_group where user_name = ''',v_user_name,'''');
      prepare s1 from @stmt;
      execute s1;
      drop prepare s1;
    end if;
end while;
-- Close cursor.
close cur1;
-- Free variable from memory.
set @stmt = NULL;
END$$
DELIMITER ;
2、试验表。
我们用一个有一千万条记录的表来做测试。
mysql&gt; select count(*) from t_group;
+----------+
| count(*) |
+----------+
| 10388608 | 
+----------+
1 row in set (0.00 sec)
表结构。
mysql&gt; desc t_group;
+-------------+------------------+------+----