[rt-users] Re: Slow Queries

[Ruslan Zakirov]

This is mysql bug that wouldn't be fixed in 4.1 branch, but is fixed
in 5.x. I know how to fix this on RT side, but it's quite hard to
implement a solution and I don't think we'll have enough time for
this. Sorry. See also http://bugs.mysql.com/?id=20182

On 10/24/06, Asif Iqbal <vadud3 at gmail.com> wrote:
> Here is another query that takes 6.95 secs
>
> Count: 198  Time=6.95s (1377s)  Lock=0.00s (0s)  Rows=1.1 (224),
> rt_user[rt_user]@localhost
>   SELECT DISTINCT main.* FROM (((Tickets main  JOIN Groups Groups_1
> ON ( Groups_1.Instance = main.id))  LEFT JOIN CachedGroupMembers
> CachedGroupMembers_2  ON ( CachedGroupMembers_2.GroupId = Groups_1.id)
> AND ( (CachedGroupMembers_2.GroupId !=
> CachedGroupMembers_2.MemberId)))  LEFT JOIN Users Users_3  ON (
> Users_3.id = CachedGroupMembers_2.MemberId))   WHERE ((Groups_1.Domain
> = 'S')) AND ((Groups_1.Type = 'S')) AND ((main.EffectiveId = main.id))
> AND ((main.Status != 'S')) AND ((main.Type = 'S')) AND ( (  (
> (Users_3.EmailAddress = 'S') )  ) AND ( (main.Status =
> 'S')OR(main.Status = 'S') ) )  ORDER BY main.Priority DESC  LIMIT N
>
> Is there a way to improve this?
>
>
> On 10/9/06, Asif Iqbal <vadud3 at gmail.com> wrote:
> > Hi
> >
> > I am noticing from my slow log file (5 secs) that the following query
> > on mysql 4.0.24 is taking a 11 secs
> >
> > # Query_time: 11  Lock_time: 0  Rows_sent: 299925  Rows_examined: 983836
> > use rt3;
> > SELECT * FROM Transactions where Transactions.type = 'create';
> >
> > Now looking at the explain I see
> >
> > mysql> explain SELECT * FROM Transactions where Transactions.type = 'create';
> > +--------------+------+---------------+------+---------+------+--------+-------------+
> > | table        | type | possible_keys | key  | key_len | ref  | rows
> > | Extra       |
> > +--------------+------+---------------+------+---------+------+--------+-------------+
> > | Transactions | ALL  | NULL          | NULL |    NULL | NULL | 984572
> > | Using where |
> > +--------------+------+---------------+------+---------+------+--------+-------------+
> >
> > It has to go thru about 1 million rows and not using any index.
> >
> > Is there any index, that I can create, to improve this w/o hurting any
> > other query?
> >
> > --
> > Asif Iqbal
> > PGP Key: 0xE62693C5 KeyServer: pgp.mit.edu
> >
>
>
> --
> Asif Iqbal
> PGP Key: 0xE62693C5 KeyServer: pgp.mit.edu
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-- 
Best regards, Ruslan.