418
votes

I am having a big problem trying to connect to mysql. When I run:

/usr/local/mysql/bin/mysql start

I have the following error :

Can't connect to local MySQL server through socket '/var/mysql/mysql.sock' (38)

I do have mysql.sock under the /var/mysql directory.

In /etc/my.cnf I have:

[client]
port=3306
socket=/var/mysql/mysql.sock

[mysqld]
port=3306
socket=/var/mysql/mysql.sock
key_buffer_size=16M
max_allowed_packet=8M

and in /etc/php.ini I have :

; Default socket name for local MySQL connects.  If empty, uses the built-in
; MySQL defaults.
mysql.default_socket = /var/mysql/mysql.sock

I have restarted apache using sudo /opt/local/apache2/bin/apachectl restart

But I still have the error.

Otherwise, I don't know if that's relevant but when I do mysql_config --sockets I get

--socket         [/tmp/mysql.sock]
30
Is MySQL running?David
That certainly explains the error in trying to connect to it. How, as @Romain mentioned, is there anything in MySQL's logs (try /var/log/mysql or somewhere around there) which indicates why it isn't running? Do you get an error when you try to start it?David
I was getting the same error, but in my case, I found out mysql wouldn't start because the disk was 100% full. /var/log/mysqld.log was helpful.yellavon
the reason they are asking if it is running, i presume, is because the socket is made when the service starts. i installed mysql, but never started the service, so the .sock file doesn't exist. type service mysqld start if you just installed. hthchangokun
Below answer of shimanyi sudo service mysql start saved meKiren S

30 Answers

225
votes

If your file my.cnf (usually in the /etc/mysql/ folder) is correctly configured with

socket=/var/lib/mysql/mysql.sock

you can check if mysql is running with the following command:

mysqladmin -u root -p status

try changing your permission to mysql folder. If you are working locally, you can try:

sudo chmod -R 755 /var/lib/mysql/

that solved it for me

94
votes

are you sure you installed mysql as well as mysql server..

For example to install mySql server I'll use yum or apt to install both mysql command line tool and the server:

yum -y install mysql mysql-server (or apt-get install mysql mysql-server)

Enable the MySQL service:

/sbin/chkconfig mysqld on

Start the MySQL server:

/sbin/service mysqld start

afterwards set the MySQL root password:

mysqladmin -u root password 'new-password' (with the quotes)

I hope it helps.

84
votes

A quick workaround that worked for me: try using the local ip address (127.0.0.1) instead of 'localhost' in mysql_connect(). This "forces" php to connect through TCP/IP instead of a unix socket.

53
votes

I got the following error

ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (111)

Tried several ways and finally solved it through the following way

sudo gksu gedit /etc/mysql/my.cnf

modified

#bind-address       = 127.0.0.1

to

bind-address        = localhost

and restarted

sudo /etc/init.d/mysql restart

it worked

33
votes

Make sure you are running mysqld : /etc/init.d/mysql start

21
votes

I got this error when I set cron job for my file. I changed the permissions of file to 777 but it still not worked for me. Finally I got the solution. May be it will be helpful for others.

Try with this command:

mysql -h 127.0.0.1 -P 3306 -u root -p

Remember that -h means host, -P means port and -p means password.

19
votes

To prevent the problem from occurring, you must perform a graceful shutdown of the server from the command line rather than powering off the server.

shutdown -h now

This will stop the running services before powering down the machine.

Based on Centos, an additional method for getting it back up again when you run into this problem is to move mysql.sock:

mv /var/lib/mysql/mysql.sock /var/lib/mysql/mysql.sock.bak

service mysqld start

Restarting the service creates a new entry called mqsql.sock

13
votes

As can be seen by the many answers here, there are lots of problems that can result in this error message when you start the MySQL service. The thing is, MySQL will generally tell you exactly what's wrong, if you just look in the appropriate log file.

For example, on Ubuntu, you should check /var/log/syslog. Since lots of other things might also be logging to this file, you probably want to use grep to look at mysql messages, and tail to look at only the most recent. All together, that might look like:

grep mysql /var/log/syslog | tail -50

Don't blindly make changes to your configuration because someone else said 'This worked for my system.' Figure out what is actually wrong with your system and you'll get a better result much faster.

12
votes

Another workaround is to edit /etc/my.cnf and include host in the section [client]

 [client]
 #password       = your_password
 host            = 127.0.0.1
 port            = 3306
 socket          = /var/run/mysql/mysql.sock

And then restarting the mysql service.

This workaround was tested in: Server version: 5.5.25a-log Source distribution

8
votes

I had the same problem and it has been caused by an update of mysql drivers when mysql server was running. I fixed it just restarting both mysql and apache2:

sudo service mysql stop

sudo service mysql start

sudo service apache2 stop

sudo service apache2 start

7
votes

try with -h (host) and -P(port):

mysql -h 127.0.0.1 -P 3306 -u root -p

6
votes

In my case, I was using Centos 5.5. I found that the problem was because the mysql service was stopped some how. So I started mysql service with the command:

 /etc/init.d/mysqld start

So.. silly mistake.

6
votes

If everything worked just fine and you just started seeing this error, before you do anything else, make sure you're not out of disk space:

df -h

If the volume where the mysql.sock is being created is at 100% use, MySql won't be able to create it and this will be the cause of this error. All you need to do is delete something that's not needed, like old log files.

6
votes
sudo service mysql start

This should serve you just fine. There could be a possibility that you changed some commands that affected the mysql configurations.

5
votes

There are many solutions to this problem but for my situation, I just needed to correct the DATE on the machine/server (Ubuntu 16.04 Server).

i) Check the date of your server and correct it.

ii) Run sudo /etc/init.d/mysql restart

That should get it started.

4
votes

I was getting the error because I was running MAMP and my .sock file was in a different location. I just added a symbolic link where the app thought it should be that pointed to where it actually was and it worked like a charm.

4
votes

If you are using AWS (Amazon Web Services) Micro version, then it is a memory issue. When I ran

mysql

from the terminal it would say

ERROR 2002 (HY000): Can't connect to local MySQL server through socket /var/run/mysqld/mysqld.sock' (111)

So I tried the following and it would just fail.

service mysqld restart

After much searching, I found out that you have to create a swap file for MySQL to have enough memory. Instructions are listed: http://www.prowebdev.us/2012/05/amazon-ec2-linux-micro-swap-space.html.

Then, I was able to restart mysqld.

4
votes

I also found that this was a permissions problem. I compared the MySQL files to a working install (both on Debian 6 squeeze) and had to make the following ownership changes (where mydatabase is any database(s) you have).

Ownership mysql:mysql:

chown mysql:mysql /var/lib/mysql
chown mysql:mysql /var/lib/mysql/ib*
chown mysql:mysql /var/lib/mysql/mydatabase
chown mysql:mysql /var/lib/mysql/mydatabase/*
chown mysql:mysql /var/lib/mysql/mysql/* 

Ownership mysql:root:

chown mysql:root /var/lib/mysql/mysql
chown mysql:root /var/run/mysqld 

Ownership mysql:adm:

chown mysql:adm /var/log/mysql
chown mysql:adm /var/log/mysql.err
chown mysql:adm /var/log/mysql.log* 
4
votes

For me - this was simply a case of MySQL taking a long time to load. I have over 100,000 tables in one of my databases and it did eventually start but obviously has to take a long time in this instance.

3
votes

you can always start mysql server by specifying the location of the mysql.sock file using the --socket option like

mysql --socket=/var/mysql/mysql.sock 

This will work even if the location of socket file in specified in a different location in the my.cnf file.

3
votes

For those whose any solution did not work, try:

cd /etc/mysql

check if my.cnf is present

nano my.cnf

and make sure you have only one bind-address as follows:

bind-address = 127.0.0.1

If not, that might be the problem, just exit nano and save the file.

and service mysql start

note that if you don't have nano (its a text editor) just install it with apt-get install nano and once in just press Ctrl+X to exit, dont forget to say Y to save and use the same file)

3
votes
sudo service mysqld start

Worked for me, I'm using Centos

3
votes

I had this problem too when trying to start the server, so many of the answers here that just say to start the server didn't work. The first thing you can do is execute the following to see if there are any config errors:

/usr/sbin/mysqld --verbose --help 1>/dev/null

I did have one error that showed up:

160816 19:24:33 [Note] /usr/sbin/mysqld (mysqld 5.5.50-0ubuntu0.14.04.1-log) starting as process 9461 ...
160816 19:24:33 [Warning] Using unique option prefix myisam-recover instead of myisam-recover-options is deprecated and will be removed in a future release. Please use the full name instead.
160816 19:24:33 [Note] Plugin 'FEDERATED' is disabled.
160816 19:24:33 [ERROR] /usr/sbin/mysqld: unknown variable 'innodb-online-alter-log-max-size=4294967296'
160816 19:24:33 [ERROR] Aborting

A simple grep -HR "innodb-online-alter-log-max-size" /etc/mysql/ showed me exactly what file contained the offending line, so I removed that line from the file.

Then, checking my /var/log/mysql/error.log file I had:

InnoDB: Error: log file ./ib_logfile0 is of different size 0 5242880 bytes
InnoDB: than specified in the .cnf file 0 671088640 bytes!
160816 22:46:46 [ERROR] Plugin 'InnoDB' init function returned error.
160816 22:46:46 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
160816 22:46:46 [ERROR] Unknown/unsupported storage engine: InnoDB
160816 22:46:46 [ERROR] Aborting

Based on this question the accepted solution wouldn't work because I couldn't even get the server started, so I followed what some of the comments said and deleted my /var/lib/mysql/ib_logfile0 and /var/lib/mysql/ib_logfile1 files.

This allowed the server to start and I was able to connect and execute queries, however checking my error log file it was quickly getting filled up with several tens of thousands of lines like this:

160816 22:52:15  InnoDB: Error: page 1415 log sequence number 82039318708
InnoDB: is in the future! Current system log sequence number 81640793100.
InnoDB: Your database may be corrupt or you may have copied the InnoDB
InnoDB: tablespace but not the InnoDB log files. See
InnoDB: http://dev.mysql.com/doc/refman/5.5/en/forcing-innodb-recovery.html
InnoDB: for more information.

Based on a suggestion from here, to fix this I did a mysqldump and restore of all databases (see the link for several other solutions).

$ mysqldump -u root -p --allow-keywords --add-drop-database --comments --hex-blob --opt --quote-names --databases db_1 db_2 db_3 db_etc > backup-all-databases.sql
$ mysql -u root -p < backup-all-databases.sql

Everything appears to be working as expected now.

2
votes

Adding

--protocol=tcp 

to the list of pramaters in your connection worked for me.

2
votes

This was good enough for me

sudo /etc/init.d/mysql restart
2
votes

I ran into this issue today. None of these answers provided the fix. I needed to do the following commands (found here https://stackoverflow.com/a/20141146/633107) for my mysql service to start:

sudo /etc/init.d/mysql stop
cd /var/lib/mysql/
ls ib_logfile*
mv ib_logfile0 ib_logfile0.bak
mv ib_logfile1 ib_logfile1.bak
... etc ...
/etc/init.d/mysql restart

This was partly indicated by the following errors in /var/log/mysql/error.log:

140319 11:58:21 InnoDB: Completed initialization of buffer pool
InnoDB: Error: log file ./ib_logfile0 is of different size 0 50331648 bytes
InnoDB: than specified in the .cnf file 0 5242880 bytes!
140319 11:58:21 [ERROR] Plugin 'InnoDB' init function returned error.
140319 11:58:21 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
140319 11:58:21 [ERROR] Unknown/unsupported storage engine: InnoDB
140319 11:58:21 [ERROR] Aborting

I also saw the disk full error, but only when running commands without sudo. If the permissions check fails, it reports disk full (even when your partition is not even close to full).

2
votes

CentOS 7, 64 bit. Fresh installation.
In my case, the error was because I didn't have the right MySQL server and MySQL client installed.
Using yum, I removed mariadb and mysql-community edition. I downloaded the rpm's for the client and server from the official MySQL website and installed the server and client.

On installing the server, I was shown a message that the password to the root account for MySQL was stored in a file which I could view with sudo cat /root/.mysql_secret.

So after installing the client and server, I checked if MySQL was working (I think I rebooted before doing so) with the command sudo service mysql status and I got the result.

MySQL running (2601) [ OK ]

I logged into MySQL using the password from the .mysql_secret file:
mysql -uroot -pdxM01Xfg3DXEPabpf. Note that dxM01Xfg3DXEPabpf is the password mentioned in the .mysql_secret file.

and then typed entered the following command at the mysql prompt to change the password of root:

mysql> SET PASSWORD FOR 'root'@'localhost' = PASSWORD('somePassword');

Everything worked fine from then on.

2
votes

This doesn't directly answer your question but a subset of it, namely using PythonAnywhere. I kept stumbling upon this question when looking for a fix so I'm adding it here in the hope that it will help others in my situation.


PythonAnywhere decided to change the database connection hostnames in order to improve efficiency and reliability, as detailed here:

The official host name you should use for connecting to your account's MySQL database instance has changed from mysql.server to yourusername.mysql.pythonanywhere-services.com. This bypasses a part of our infrastructure that has started showing problems in recent weeks, and it should be much more efficient and reliable than the old way.

Hence, you will need to update your hostname to the value highlighted above.

2
votes

I've just had this problem. after a day of checking finally I've got the answer with that The mysql.sock file is created when MariaDB starts and is removed when MariaDB is shutdown. It won't exist if MariaDB is not running. maybe you didn't install MariaDB. YOU COULD FOLLOW THE INSTRUCTION BELOW: https://www.linode.com/docs/databases/mariadb/how-to-install-mariadb-on-centos-7 BEST

1
votes

I had this socket error and it basically came down to the fact that MySQL was not running. If you run a fresh install, make sure that you install 1) the system package and 2) the panel installer (mysql.prefPane). The panel installer will allow you to goto your System Preferences and open MySQL, and then get an instance running.

Note that, on a fresh install, I needed to reset my computer for the changes to properly take effect. Following a reboot, I got a new instance running and was able to open up a connection to localhost with no problem.

Also of note, I apparently had previous versions of MySQL installed but had removed the panel, which makes it easy to get an instance of MySQL running for mac users.

A good link for this process of reinstalling: http://www.coolestguyplanettech.com/how-to-install-php-mysql-apache-on-os-x-10-6/