Hi,

What is the Use of MySQL Server Variables?

Regards
sivaraman.

hi...

Mysql server have many server variables, they are used to configure the various components and aspects of the MySQL server, storage engines, client, and support tools. Each system variable has a default value. System variables can be set at server startup. Most of them can be changed dynamically while the server is running by means of the SET statement, which enables you to modify operation of the server without having to stop and restart it.


Regards,
S.Ashokkumar

Are the system variable can be changed by any user or only by admin user ?

Also let me know if we can able to allow (Partially, limited access to modify the system variables) a common user to modify the system variables ?

__________________
Keep smiling...

The User who has privilege to create session and alter session can modify some basic system variable as per the session.

__________________
-Murali..

Hi,

I want to change some variable values in mysql datebase (EX:system_time_zone,wait_timeout,sort_buffer_size ) is it possible in sever variable.

Regards
sivaraman

Hi Sivaram,

Yes u change the values of some server variables manually for active session using commands below,

SHOW variables LIKE 'wait_timeout';
SHOW variables LIKE 'sort_buffer_size';
Where as the system_time_zone variable could not be changed due to the reason there will be some job scheduling which activates the time zone variable as per daylight savings.

Hope its clear !!!

__________________
-Murali..

hi...

We can change the some server variable globally....

Syntax :

SET GLOBAL variable_name = value;

Example :

SET GLOBAL group_concat_max_len = 65535;


If we change a session system variable, the value remains in effect until our session ends or until we change the variable to a different value. The change is not visible to other clients.

If we change a global system variable, the value is remembered and used for new connections until the server restarts. The change affects the corresponding session variable only for clients that connect after the change.


Regards,
S.Ashokkumar.

Yes Ashok we can set the values for some global variable present in the server temporarily till the system restarts.

If we need that value to be set permanently then we need to change the server parameter values in the mysql config file.

__________________
-Murali..