Jonathan López » MySQL

Change MySQL variables without restart

Jonathan — Tue, 15 Apr 2008 23:03:24 +0000

A simple way to change runtime variables wihtout restarting mysql server.

First check the running value:

mysql> show variables like 'long_query%'; +-----------------+-------+ | Variable_name | Value | +-----------------+-------+ | long_query_time | 10 | +-----------------+-------+

Change the value:

mysql> set @@long_query_time=2;

Check again:

mysql> show variables like 'long_query%'; +-----------------+-------+ | Variable_name | Value | +-----------------+-------+ | long_query_time | 2 | +-----------------+-------+

Success!

Could not connect to database for SQL SessionHandler

Jonathan — Thu, 03 Apr 2008 21:00:57 +0000

When you try to login in Horde you see this error:

A fatal error has occurred
Could not connect to database for SQL SessionHandler.
Details have been logged for the administrator.

There are some different reasons that causes this error. This is a checklist to solve the problem.

First, check the /etc/my.cnf and remove skip-innodb if its in there.

Second, repair Horde database

mysqlcheck --auto-repair horde

Third, enter mysql and check what socket file is using mysql:

# mysql mysql> show variables like 'socket';

You must see something like this:

socket /var/lib/mysql/mysql.sock

Edit the config file:

vi /usr/local/cpanel/base/horde/config/conf.php

Change the following two lines from:

$conf['sql']['hostspec'] = 'localhost'; $conf['sessionhandler']['params']['hostspec'] = 'localhost';

to:

$conf['sql']['hostspec'] = 'localhost:/var/lib/mysql/mysql.sock'; $conf['sessionhandler']['params']['hostspec'] = 'localhost:/var/lib/mysql/mysql.sock';

Cambiar password de root de MySQL

Jonathan — Tue, 18 Dec 2007 22:17:21 +0000

Pasos para cambiar la contraseña del usuario root para el servicio MySQL:

1º Parar cualquier instancia del servicio

/etc/init.d/mysql stop

2º Iniciar MySQL en modo seguro

/usr/bin/mysqld_safe --skip-grant-tables

3º Ejecutamos el cliente de MySQL y seleccionamos la base de datos mysql

mysql

use mysql;

4º Actualizamos la contraseña del usuario root

update user set Password=('password') where user='root';

5º Recargar las tablas de permisos

flush privileges

6º Por ultimo, parar mysql e iniciarlo de forma normal.