Check performance with script :
http://mysqltuner.pl/mysqltuner.pl - Variable tunning
http://hackmysql.com/mysqlidxchk - Unused Index
Thanks,
Prabhat
On Thu, May 24, 2012 at 4:32 PM, Rick James <rjames@stripped> wrote:
> Thanks. I got tired of answering the same questions about buffer_pool and
> key_buffer over and over on forums.mysql.com; now I just point people at
> that page.
>
> INT(1) and INT(50) are identical -- and take 4 bytes. See TINYINT,
> BIGINT, etc. Also, UNSIGNED is probably wanted in more places than you
> have it.
>
> 555KB is not very big. But a table scan (as indicated by the EXPLAIN)
> costs something.
>
> select * -- Is this what you are really fetching? If not, we
> can discuss a "covering" index.
> from thold_data
> where thold_enabled='on' -- 2-valued flag? Not likely to be useful in
> an index, esp. not by itself
> AND data_id = 91633; -- Probably the best bet.
>
> Recommend:
> INDEX(data_id) -- or UNIQUE, if it is unique
> INDEX(data_id, thold_enabled) -- or the opposite order; this probably
> would not be noticeable better.
>
> `notify_default` enum('on','off') default NULL
> Did you really mean to have 3 values (on, off, NULL)?
>
>
>
> > -----Original Message-----
> > From: Yu Watanabe [mailto:yu.watanabe@stripped]
> > Sent: Wednesday, May 23, 2012 7:10 PM
> > To: mysql@stripped
> > Subject: Re: Need help for performance tuning with Mysql
> >
> > Rick
> >
> > Thank you for the reply.
> >
> > >1. There are only a few things worth tuning -- see
> > >http://mysql.rjweb.org/doc.php/memory (they don't include the ones you
> > >tried)
> > >
> >
> > The page is really cool. Its very simple and easy to understand.
> >
> > >2. Instead INDEXes and schema design must be studied. Please provide:
> > >SHOW CREATE TABLE
> >
> > | thold_data | CREATE TABLE `thold_data` (
> > `id` int(11) NOT NULL auto_increment,
> > `rra_id` int(11) NOT NULL default '0',
> > `data_id` int(11) NOT NULL default '0',
> > `thold_hi` varchar(100) default NULL,
> > `thold_low` varchar(100) default NULL,
> > `thold_fail_trigger` int(10) unsigned default NULL,
> > `thold_fail_count` int(11) NOT NULL default '0',
> > `thold_alert` int(1) NOT NULL default '0',
> > `thold_enabled` enum('on','off') NOT NULL default 'on',
> > `bl_enabled` enum('on','off') NOT NULL default 'off',
> > `bl_ref_time` int(50) unsigned default NULL,
> > `bl_ref_time_range` int(10) unsigned default NULL,
> > `bl_pct_down` int(10) unsigned default NULL,
> > `bl_pct_up` int(10) unsigned default NULL,
> > `bl_fail_trigger` int(10) unsigned default NULL,
> > `bl_fail_count` int(11) unsigned default NULL,
> > `bl_alert` int(2) NOT NULL default '0',
> > `lastread` varchar(100) default NULL,
> > `oldvalue` varchar(100) NOT NULL default '',
> > `repeat_alert` int(10) unsigned default NULL,
> > `notify_default` enum('on','off') default NULL,
> > `notify_extra` varchar(255) default NULL,
> > `host_id` int(10) default NULL,
> > `syslog_priority` int(2) default '3',
> > `cdef` int(11) NOT NULL default '0',
> > PRIMARY KEY (`id`),
> > KEY `rra_id` (`rra_id`)
> > ) ENGINE=MyISAM AUTO_INCREMENT=69641 DEFAULT CHARSET=latin1 |
> >
> > >SHOW TABLE SIZE
> >
> > You must be mentioning about the "show table status"
> >
> > mysql> show table status where name = "thold_data";
> > +------------+--------+---------+------------+------+----------------+-
> > ------------+-----------------+--------------+-----------+-------------
> > ---+---------------------+---------------------
> > +---------------------+-------------------+----------+----------------
> > +---------+
> > | Name | Engine | Version | Row_format | Rows | Avg_row_length |
> > Data_length | Max_data_length | Index_length | Data_free |
> > Auto_increment | Create_time | Update_time | Check_time
> > | Collation | Checksum | Create_options | Comment |
> > +------------+--------+---------+------------+------+----------------+-
> > ------------+-----------------+--------------+-----------+-------------
> > ---+---------------------+---------------------
> > +---------------------+-------------------+----------+----------------
> > +---------+
> > | thold_data | MyISAM | 10 | Dynamic | 6161 | 90 |
> > 555128 | 281474976710655 | 140288 | 0 | 70258 |
> > 2012-05-24 10:41:47 | 2012-05-24 10:47:19 | 2012-05-24
> > 10:41:47 | latin1_swedish_ci | NULL | | |
> > +------------+--------+---------+------------+------+----------------+-
> > ------------+-----------------+--------------+-----------+-------------
> > ---+---------------------+---------------------
> > +---------------------+-------------------+----------+----------------
> > +---------+
> > 1 row in set (0.00 sec)
> >
> > >EXPLAIN SELECT
> >
> > I have seen the following select query in the slow query log.
> > I also saw update queries as well.
> >
> > mysql> explain select * from thold_data where thold_enabled='on' AND
> > mysql> data_id = 91633;
> > +----+-------------+------------+------+---------------+------+--------
> > -+------+------+-------------+
> > | id | select_type | table | type | possible_keys | key | key_len
> > | ref | rows | Extra |
> > +----+-------------+------------+------+---------------+------+--------
> > -+------+------+-------------+
> > | 1 | SIMPLE | thold_data | ALL | NULL | NULL | NULL
> > | NULL | 6161 | Using where |
> > +----+-------------+------------+------+---------------+------+--------
> > -+------+------+-------------+
> > 1 row in set (0.06 sec)
> >
> > If cache size tuning is not an option ,
> > do you think that following action would be an choice to faten the
> > queries little bit more?
> >
> > 1. depriving the database and setup as an another process. (multiple
> > mysql processes) 2. Move the MYD, MYI, frm to ram disk (/dev/shm)
> >
> > Thanks,
> > Yu
> >
> > Rick James さんは書きました:
> > >100% CPU --> A slow query. Tuning will not help. Period.
> > >
> > >1. There are only a few things worth tuning -- see
> > >http://mysql.rjweb.org/doc.php/memory (they don't include the ones you
> > >tried)
> > >
> > >2. Instead INDEXes and schema design must be studied. Please provide:
> > >SHOW CREATE TABLE
> > >SHOW TABLE SIZE
> > >EXPLAIN SELECT ...
> > >
> > >
> > >> -----Original Message-----
> > >> From: Yu Watanabe [mailto:yu.watanabe@stripped]
> > >> Sent: Tuesday, May 22, 2012 7:07 PM
> > >> To: mysql@stripped
> > >> Subject: Need help for performance tuning with Mysql
> > >>
> > >> Hello all.
> > >>
> > >> I would like to ask for advice with performance tuning with MySQL.
> > >>
> > >> Following are some data for my server.
> > >>
> > >> CPU : Xeon(TM) 2.8GHz (2CPUs - 8core total)
> > >> Memory : 8GB
> > >> OS : RHEL 4.4 x86_64
> > >> MySQL : MySQL 5.0.50sp1-enterprise
> > >>
> > >> Attached file
> > >> # my.cnf.txt : my.cnf information
> > >> # mysqlext_20120522131034.log : variable and status information from
> > >> mysqladmin
> > >>
> > >> I have 2 database working with high load.
> > >>
> > >> I wanted to speed up my select and update queries not by optimizing
> > >> the query itself but tuning the my.cnf.
> > >>
> > >> I have referred to following site,
> > >> http://dev.mysql.com/doc/refman/5.0/en/server-status-variables.html
> > >>
> > >> and read "Hiperformance Mysql vol.2" , and increased the following
> > >> values,
> > >>
> > >> table_cache
> > >> thread_cache_size
> > >> tmp_table_size
> > >> max_heap_table_size
> > >>
> > >> but made not much difference.
> > >>
> > >> According to the ps and sar result
> > >>
> > >> *1 PS result
> > >> Date Time CPU% RSS VSZ
> > >> 2012/5/22 21:00:39 109 294752 540028
> > >>
> > >> *2 SAR
> > >> Average CPU user 25%
> > >> sys 5%
> > >> io 3%
> > >>
> > >> I assume that MySQL can work more but currently not.
> > >>
> > >> I am considersing to off load 1 high load database to seperate
> > >> process and make MySQL work in multiple process.
> > >>
> > >> It would be a great help if people in this forum can give us an
> > >> adivice for the tuning.
> > >>
> > >> Best Regards,
> > >> Yu Watanabe
> > >
> > >
> >
> >
> > --
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>
>
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>
--
Best Regards,
Prabhat Kumar
MySQL DBA
My Blog: http://adminlinux.blogspot.com
My LinkedIn: http://www.linkedin.com/in/profileprabhat
