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mysqldatabaseglobal-variablessystem-variablemysql-variables

Cannot set a global variable on MySQL

I'm using MySQL in localhost (in ubuntu and also in windows). I want to set a global variable, and I have tried in all ways but even though I get an "ok" message from mysql, then when I do the "select @var" it allways says "NULL". I've tried:

set global var=17;
set @global.var=17;
set @@var=17;

Can anyone help me?

Thanks in advance.

ps: I have the SUPER privilege.

Solution

  • The variable name var does not reference a valid system variable. The GLOBAL and SESSION keywords in the SET statement are used for specifying the scope when setting MySQL system variables, not MySQL user variables.

    Try for example:

    SELECT @@global.net_read_timeout ;

SET GLOBAL net_read_timeout = 45 ;

SELECT @@global.net_read_timeout ;

    http://dev.mysql.com/doc/refman/8.0/en/set-statement.html

    http://dev.mysql.com/doc/refman/5.5/en/set-statement.html