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Buttle Butkus
Asked: 2012-01-06 02:12:27 +0800 CST

Set group_concat_max_len permanently (MySQL config)

  • 772

I have MySQL installed on an Ubuntu machine.

I added this line in /etc/mysql/my.cnf

group_concat_max_len=15360

But there is no effect. Every time I restart mysql, the value is set to 1,024. I have to manually run

SET GLOBAL group_concat_max_len=15360

...every time I start up mysql.

Why is my.cnf not working the way I thought it should? Thank you

ubuntu mysql

3 Answers

  1. Best Answer

    If you have the setting already in my.cnf or my.cfg, and a restart did not bring about the change you expected, you may just have the setting placed in the wrong location.

    Make sure the setting is under the [mysqld] group header

    [mysqld]
group_concat_max_len=15360

    then you can restart mysqld without worry

    BTW @gbn may be more correct in this instance because you cannot use commas in the numerical settings for my.cnf (+1 for @gbn)

    • 33

  2. Use group_concat_max_len=15360 without the thousands separator

    See the docs

    If this doesn't persist, then you need to identify the correct my.cnf or my.cfg used by your installation

    • 5

  3. Here is what I do:
    Open MySQL Workbench and select the connection you want to manipulate if you have more than one, then click Server Administration - Advanced - Various, select group_concat_max_len and set your long desired value.
    Remember to restart MySql.
    Kind regards, Ola Balstad.

    • 0