As you are selecting all records (no where clause), it will scan the whole table every time, I believe...
does anyone know if he added the other columns to his index, or had 4 seperate indexes (one per column) would they be used in this operation? > > Ok, I've found the optimization chapter in the manual and I'm still > reading it. > Here's what I've done so far: > > mysql> alter table traf_oper add index (tel), add index (telefb); > > mysql> explain select tel, telefb, rutaentran, rutasalien, > sum(minutos) > as minutos from traf_oper group by 1, 2, 3, 4; > +----+-------------+-----------+------+---------------+------+ > ---------+------+---------+---------------------------------+ > | id | select_type | table | type | possible_keys | key > | key_len | > ref | rows | Extra | > +----+-------------+-----------+------+---------------+------+ > ---------+------+---------+---------------------------------+ > | 1 | SIMPLE | traf_oper | ALL | NULL | NULL > | NULL | > NULL | 5014313 | Using temporary; Using filesort | > +----+-------------+-----------+------+---------------+------+ > ---------+------+---------+---------------------------------+ > 1 row in set (0.50 sec) > > mysql> describe traf_oper; > +------------+----------+-------------------+------+-----+---- > -----+-------+ > | Field | Type | Collation | Null | Key | > Default | Extra | > +------------+----------+-------------------+------+-----+---- > -----+-------+ > | tel | char(8) | latin1_swedish_ci | YES | MUL | > NULL | | > | fecha | char(8) | latin1_swedish_ci | YES | | > NULL | | > | hora | char(6) | latin1_swedish_ci | YES | | > NULL | | > | telefb | char(14) | latin1_swedish_ci | YES | MUL | > NULL | | > | tiempotasa | char(6) | latin1_swedish_ci | YES | | > NULL | | > | rutasalien | char(7) | latin1_swedish_ci | YES | | > NULL | | > | rutaentran | char(7) | latin1_swedish_ci | YES | | > NULL | | > | serie | char(3) | latin1_swedish_ci | YES | | > NULL | | > | tipotraf | int(1) | binary | YES | | > NULL | | > | minutos | int(4) | binary | YES | | > NULL | | > +------------+----------+-------------------+------+-----+---- > -----+-------+ > 10 rows in set (0.00 sec) > > So, why isn't SELECT using indexes (key = NULL, key_len = NULL)? > Where else do I need to add indexes? > Thanks for your help! > > > -- > MySQL General Mailing List > For list archives: http://lists.mysql.com/mysql > To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED] -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
