EXPLAIN EXTENDED

CREATE TABLE t_text (
       id INT NOT NULL AUTO_INCREMENT,
     value VARCHAR(200) NOT NULL,
        PRIMARY KEY(id),
    KEY ix_text_value (value)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE TEMPORARY TABLE t_filler (
 id INT NOT NULL PRIMARY KEY
);

CREATE TEMPORARY TABLE t_letters (
 id INT NOT NULL PRIMARY KEY
);

DELIMITER $$

CREATE PROCEDURE prc_fill_filler (cnt INT)
BEGIN
    DECLARE _cnt INT;
   SET _cnt := 1;
      WHILE _cnt <= cnt DO
                INSERT
              INTO    t_filler
            VALUES  (_cnt);
             SET _cnt := _cnt + 1;
       END WHILE;
  SET _cnt := 1;
      WHILE _cnt <= 20 DO
         INSERT
              INTO    t_letters
           VALUES  (_cnt);
             SET _cnt := _cnt + 1;
       END WHILE;
END
$$

DELIMITER ;

START TRANSACTION;
CALL prc_fill_filler (100000);
COMMIT;

SET @l_vowels = 'aeiouy';
SET @u_vowels = UPPER(@l_vowels);
SET @l_consonants = 'bcdfghjklmnpqrstvwxz';
SET @u_consonants = UPPER(@l_consonants);

INSERT
INTO   t_text (id, value)
SELECT    id,
 CONCAT(
             CASE
                        WHEN rnd < 0.05 THEN 'A '
                 WHEN rnd < 0.1 THEN 'The '
                        ELSE ''
           END,
                (
           SELECT  GROUP_CONCAT(
                       IF(
                 (slen - id) % 2 = 0,
                        SUBSTR(IF(l.id = 1, @u_vowels, @l_vowels), FLOOR(RAND(20090323) * LENGTH(@l_vowels) + 1), 1), 
                      SUBSTR(IF(l.id = 1, @u_consonants, @l_consonants), FLOOR(RAND() * LENGTH(@l_consonants) + 1), 1)
                    )
                   ORDER BY l.id
                       SEPARATOR '')
             FROM    t_letters l
         WHERE   l.id <= slen
                )
   )
FROM       (
   SELECT  id,
         RAND(20090323) AS rnd,
              FLOOR(RAND() * 10) + 4 AS slen
      FROM    t_filler
    ) q;

DROP TABLE t_filler;
DROP TABLE t_letters;