List:General Discussion« Previous MessageNext Message »
From:spameden Date:April 9 2013 6:57am
Subject:Re: How to tweek the max connections
View as plain text  
2013/4/9 Rick James <rjames@stripped>

> There is no "exact" calculation.  Too many buffers, etc, are allocated (or
> not) on a per-thread, or even per-subquery basis, that it is impractical to
> compute a totally "safe" value for the various tunables.
>

I tend to agree with you, but you can calculate approximate values which
mysqld might use.


> Here's my discussion on such:
>    http://mysql.rjweb.org/doc.php/memory
> max_connections is a minor player in memory usage.
>
> The STATUS value Max_used_connections gives the high-water-mark (since
> startup) toward using up all of max_connections.
>

Check
https://raw.github.com/rackerhacker/MySQLTuner-perl/master/mysqltuner.pl as
well

>
> > -----Original Message-----
> > From: spameden [mailto:spameden@stripped]
> > Sent: Monday, April 08, 2013 4:32 AM
> > To: Yu Watanabe
> > Cc: mysql@stripped
> > Subject: Re: How to tweek the max connections
> >
> > Is it really so hard?
> >
> > http://bit.ly/YG6JQn
> >
> > first link shows how it works.
> >
> > NOTE: it seems your MySQL setup might be using SWAP so be careful it
> > can lead to slowdowns.
> >
> >
> > 2013/4/8 Yu Watanabe <yu.watanabe@stripped>
> >
> > > Hi all!
> > >
> > > I would like know if there are any calculatios for specifying the
> > > maximum number of the 'max_connections' value.
> > >
> > > I understand that max_connections should be decided by the remaining
> > > RAM size of the system. But exactly how should it be actually
> > > calculated?
> > >
> > > I am currently using RHEL 5.3 32 bit and following are samples of the
> > > memory usage of my system.
> > >
> > > [root@GWM bin]# ps -eo "pcpu,vsz,rss,args" | grep mysql
> > >  0.0   5420  1172 /bin/sh /usr/bin/mysqld_safe --
> > datadir=/var/lib/mysql
> > > --pid-file=/var/lib/mysql/GWM.pid
> > >  0.0 332592 40040 /usr/sbin/mysqld --basedir=/usr
> > > --datadir=/var/lib/mysql --plugin-dir=/usr/lib/mysql/plugin
> > > --user=mysql --log-error=/var/lib/mysql/GWM.err
> > > --pid-file=/var/lib/mysql/GWM.pid -- socket=/var/lib/mysql/mysql.sock
> > --port=3306
> > >  0.0   4980   760 grep mysql
> > >
> > > [root@GWM bin]# free
> > >              total       used       free     shared    buffers
> > cached
> > > Mem:      16623956   12727012    3896944          0     103668
> > 11634904
> > > -/+ buffers/cache:     988440   15635516
> > > Swap:     10482404       1368   10481036
> > >
> > > Version of mysql is ,
> > >
> > > [root@GWM bin]# mysqladmin -u root --password=groundwork variables |
> > > grep version
> > > | version                                           | 5.5.25-log
> > >
> > >                       |
> > > | version_comment                                   | MySQL Community
> > > Server (GPL)
> > >                             |
> > > | version_compile_machine                           | i686
> > >
> > >                       |
> > > | version_compile_os                                | Linux
> > >
> > > Thanks,
> > > Yu
> > >
> > >
> > > --
> > > MySQL General Mailing List
> > > For list archives: http://lists.mysql.com/mysql
> > > To unsubscribe:    http://lists.mysql.com/mysql
> > >
> > >
>

Thread
How to tweek the max connectionsYu Watanabe8 Apr
  • Re: How to tweek the max connectionsspameden8 Apr
    • RE: How to tweek the max connectionsRick James9 Apr
      • Re: How to tweek the max connectionsspameden9 Apr