maria-discuss team mailing list archive

[Federico Razzoli <federico_raz@xxxxxxxx>]

Hi Sergej,

Thank you for this update. I'm still curious: does CONNECT read the rows several times? If so, is there a way to avoid this until the bug is solved?

Regards,
Federico


--------------------------------------------
El lun, 12/5/14, Sergei Golubchik <serg@xxxxxxxxxxx> escribió:

 Asunto: Re: [Maria-discuss] EXPLAIN and CONNECT
 Para: "Federico Razzoli" <federico_raz@xxxxxxxx>
 CC: maria-discuss@xxxxxxxxxxxxxxxxxxx
 Fecha: lunes, 12 de mayo, 2014 15:40
 
 Hi, Federico!
 
 On Mar 27, Federico Razzoli
 wrote:
 > Hi Sergei
 >
 
 > You can repeat this very easily:
 > 
 > MariaDB [test]>
 CREATE TABLE t_connect (c INT PRIMARY KEY) ENGINE=CONNECT
 TABLE_TYPE=CSV;
 > Query OK, 0 rows
 affected, 1 warning (0.11 sec)
 > 
 > Warning (Code 1105): No file name. Table
 will use t_connect.csv
 > MariaDB
 [test]> INSERT INTO t_connect VALUES (1),(2);Query OK, 2
 rows affected (0.00 sec)
 > Records: 2 
 Duplicates: 0  Warnings: 0
 > 
 > MariaDB [test]> EXPLAIN SELECT MAX(c)
 FROM t_connect;
 >
 +------+-------------+-----------+------+---------------+------+---------+------+------+-------+
 > | id   | select_type | table 
    | type | possible_keys | key  | key_len |
 ref  | rows | Extra |
 >
 +------+-------------+-----------+------+---------------+------+---------+------+------+-------+
 > |    1 | SIMPLE      | t_connect |
 ALL  | NULL          | NULL | NULL    | NULL |   
 4 |       |
 >
 +------+-------------+-----------+------+---------------+------+---------+------+------+-------+
 > 1 row in set (0.00 sec)
 > 
 > But adding more
 rows, the difference between the rows value and the reality
 becomes big.
 
 Thanks,
 I've reported it as
 
 https://mariadb.atlassian.net/browse/MDEV-6232
 
 I tried to repeat it earlier,
 but then it uncovered other bugs in the
 CONNECT indexes, they're fixed now. Your
 original query gets "Table was
 optimized away", so I have to modified it
 a bit for the bug report.
 
 Regards,
 Sergei