Can't connect to local MySQL server through socket

chris (2004-07-06 23:45:43)
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1 replies
I have been asked this mysql socket question a thousand times, so I decided to document the post-installation process you should go through to ensure that all the permissions are as they should be for your mysql installation.

The error generally looks like the following:

Can't connect: Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)

The usual fix for these errors is to go through the MySQL post installation process as documented below: (note this is also documented on the mysql documentation site)

shell> groupadd mysql
shell> useradd -g mysql mysql
shell> gunzip < mysql-VERSION.tar.gz | tar -xvf -
shell> cd mysql-VERSION
shell> ./configure --prefix=/usr/local/mysql
shell> make
shell> make install
shell> scripts/mysql_install_db
shell> chown -R root /usr/local/mysql
shell> chown -R mysql /usr/local/mysql/var
shell> chgrp -R mysql /usr/local/mysql
shell> cp support-files/my-medium.cnf /etc/my.cnf
shell> /usr/local/mysql/bin/mysqld_safe --user=mysql &

If your version of MySQL is older than 4.0, use safe_mysqld rather than mysqld_safe


If you want more ideas, then read on. Below is how I have documented the MySQL installation process on servers within my own organisation:

Create a new my.cnf in your /etc directory,
containing the following directives:

[mysqld]
datadir=/export/data
log=/var/log/mysql-messages

# move the compressed archive from it's
download location into a convenient build area
cd /usr/src && mv /home/user/mysql-standard-4.0.13-pc-linux-i686.tar.gz .

# extract and create a symlinked mysql directory
tar -zxvf mysql-standard-4.0.13-pc-linux-i686.tar.gz
ln -s mysql-standard-4.0.13-pc-linux-i686 mysql

# create new mysql user
/usr/sbin/groupadd mysql
/usr/sbin/useradd -g mysql mysql


# create a data directory
mkdir /export/data

# build the default mysql databases
cd /usr/src/mysql
scripts/mysql_install_db
chown -R root .
chown -R mysql data
chown -R mysql /export/data
chgrp -R mysql .

# finally, symlink to mysql's usual location
cd /usr/local/
ln -s /usr/src/mysql mysql

# end of mysql installation

# start server
bin/mysqld_safe --user=mysql &

note that this means that any upgrades to the
mysql installation will atomatically fall into place,
so long as they are symlinked to /usr/src/mysql
as was explained at the beginning of this section.


Hope that helps,

Christo
comment
chris
2005-03-16 17:51:07

an additional note - on some systems you will need to run a chown under /var as shown:

$ chown -R mysql.mysql /var/lib/mysql/*



christo





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