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From:Jesper Wisborg Krogh Date:December 9 2009 10:07am
Subject:Re: MySQL variables
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On 09/12/2009, at 6:56 PM, machiel.richards wrote:

> Good day guys (and girls if any)
>
>
>
>                 I am constantly in a position where variables on a
> production mysql database needs to be changed.
>
>
>
>                 The database runs a 24/7 system and thus to reboot  
> is not
> preffered and should be the absolute last resort.
>
>
>
>                 How can I set variables to be effective  
> immediately?   ( I
> am still a junior in mysql dba and still learning)

If you take a look at the manual in the section about server options  
and variables (http://dev.mysql.com/doc/refman/5.0/en/mysqld-option- 
tables.html in MySQL 5.0 or http://dev.mysql.com/doc/refman/5.1/en/ 
mysqld-option-tables.html in MySQL 5.1), then you can see which  
settings can be changed dynamically. To change a variable dynamically  
you need to have super privilege, and then set the variable as e.g.

SET GLOBAL system_var_name = ...

>
>                 If I set these will it still be effective should the
> database be restarted somewhere in the future?

The change above will not persist when the database is restarted. In  
order to ensure that, you will have to update the configuration file  
as well.

- Jesper

>
>
>
>                 Thanks in advance for your help.
>
>
>
> Regards
>
>
>
>
>

Thread
MySQL variablesmachiel.richards9 Dec
  • Re: MySQL variablesJesper Wisborg Krogh9 Dec