[rt-users] mysql 5.1 slow query in RT

[Ruslan Zakirov]

Added bug into mysql tracker http://bugs.mysql.com/bug.php?id=37680

Some developers suggest to test mysql 5.1.25

On Thu, May 29, 2008 at 7:20 PM, Mike Zupan <hijinks at gmail.com> wrote:
> We moved our RT server from mysql 4.0 to 5.1 and we are having some slow
> query issues on the Attachments table not finding the correct index
>
>
> mysql> explain SELECT main.* FROM Attachments main WHERE (main.Parent =
> '308267') AND (main.ContentType = 'text/plain') ORDER BY main.id ASC;
> +----+-------------+-------+-------+----------------------------------+---------+---------+------+---------+-------------+
> | id | select_type | table | type | possible_keys | key | key_len | ref |
> rows | Extra |
> +----+-------------+-------+-------+----------------------------------+---------+---------+------+---------+-------------+
> | 1 | SIMPLE | main | index | Attachments3,Attachments4,Parent | PRIMARY | 4
> | NULL | 1321158 | Using where |
> +----+-------------+-------+-------+----------------------------------+---------+---------+------+---------+-------------+
> 1 row in set (0.00 sec)
>
>
> mysql> explain SELECT main.* FROM Attachments main FORCE INDEX(Attachments3)
> WHERE (main.Parent = '308267') AND (main.ContentType = 'text/plain') ORDER
> BY main.id ASC;
> +----+-------------+-------+------+---------------+--------------+---------+-------+------+-----------------------------+
> | id | select_type | table | type | possible_keys | key | key_len | ref |
> rows | Extra |
> +----+-------------+-------+------+---------------+--------------+---------+-------+------+-----------------------------+
> | 1 | SIMPLE | main | ref | Attachments3 | Attachments3 | 4 | const | 1 |
> Using where; Using filesort |
> +----+-------------+-------+------+---------------+--------------+---------+-------+------+-----------------------------+
> 1 row in set (0.00 sec)
>
>
> It works if I choose to force the index.
>
> I have been trying to find where in the code this is to at least force the
> index but I have not found it.
>
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-- 
Best regards, Ruslan.