Acabo de hacer una prueba de laboratorio borre y cree nuevamente el PK y ahora anda mejor
Código SQL:
Ver originalmysql> SELECT SQL_NO_CACHE COUNT(c_id) FROM myTabla WHERE c_id = 2;
+--------------+
| COUNT(c_id) |
+--------------+
| 17563648 |
+--------------+
1 ROW IN SET (5.64 sec)
Código SQL:
Ver originalmysql> SELECT SQL_NO_CACHE MIN(noRow) AS MIN,MAX(noRow) AS MAX FROM myTabla WHERE c_id = 2;
+----------+----------+
| MIN | MAX |
+----------+----------+
| 18022057 | 35585704 |
+----------+----------+
1 ROW IN SET (8.36 sec)
Código SQL:
Ver originalmysql> EXPLAIN SELECT SQL_NO_CACHE c_id FROM myTabla WHERE c_id = 2 AND (noRow BETWEEN 18022057 AND 35585704);
+----+-------------+----------+------+-----------------+---------+---------+-------+----------+--------------------------+
| id | select_type | TABLE | TYPE | possible_keys | KEY | key_len | REF | ROWS | Extra |
+----+-------------+----------+------+-----------------+---------+---------+-------+----------+--------------------------+
| 1 | SIMPLE | myTabla | REF | PRIMARY,Index_2 | Index_2 | 2 | const | 17563767 | USING WHERE; USING INDEX |
+----+-------------+----------+------+-----------------+---------+---------+-------+----------+--------------------------+
1 ROW IN SET (0.00 sec)
la PK es
noRow, como ven estos resultados ?
se podria optimizar mas ?
Saludos!