Mysql problem: no mysql.sock

Question

Yesterday I was working using MySQL installed on my computer.
I downloaded xampp, so I have I changed on my.cnf file the path to the socket:

 /opt/lampp/var/mysql/mysql.sock  

That file was just there. Today I wanted to keep working on it, and I found that file is not there anymore, so I am getting the following error while I am starting mysql server:

ERROR 2002 (HY000): 
Can't connect to local MySQL server through socket 
'/opt/lampp/var/mysql/mysql.sock' (2)

Here are some tests I made:

mujeresponja@ubuntu:~$ ps -fea | grep mysqld
1000     15707 15615  0 16:28 pts/1    00:00:00 grep --color=auto mysqld
mujeresponja@ubuntu:~$ ps -fea | grep mysql 
1000     15709 15615  0 16:29 pts/1    00:00:00 grep --color=auto mysql

As a possible solution I uninstalled xampp and reinstall it, and also a new MySQL server, just in case. Anyway, that file is not there anymore.

EDIT Where the mysql.sock should be, instead there are two files mysql_upgrade_info (Which contains just 5.5.8) and another binary file called ubuntu.err:

mujeresponja@ubuntu:/opt/lampp/var/mysql$ sudo cat ubuntu.err 
110403 17:28:52 mysqld_safe Starting mysqld daemon with databases from /opt/lampp/var/mysql
110403 17:28:52 [Note] Plugin 'FEDERATED' is disabled.
/opt/lampp/sbin/mysqld: Can't find file: './mysql/plugin.frm' (errno: 13)
110403 17:28:52 [ERROR] Can't open the mysql.plugin table. Please run mysql_upgrade to create it.
InnoDB: The InnoDB memory heap is disabled
InnoDB: Mutexes and rw_locks use InnoDB's own implementation
InnoDB: Compressed tables use zlib 1.2.3
110403 17:28:52  InnoDB: Initializing buffer pool, size = 16.0M
110403 17:28:52  InnoDB: Completed initialization of buffer pool
110403 17:28:52  InnoDB: Operating system error number 13 in a file operation.
InnoDB: The error means mysqld does not have the access rights to
InnoDB: the directory.
InnoDB: File name /opt/lampp/var/mysql/ibdata1
InnoDB: File operation call: 'create'.
InnoDB: Cannot continue operation.
110403 17:28:52 mysqld_safe mysqld from pid file /opt/lampp/var/mysql/ubuntu.pid ended
110403 17:29:22 mysqld_safe Starting mysqld daemon with databases from /opt/lampp/var/mysql
110403 17:29:22 [Note] Plugin 'FEDERATED' is disabled.
/opt/lampp/sbin/mysqld: Can't find file: './mysql/plugin.frm' (errno: 13)
110403 17:29:22 [ERROR] Can't open the mysql.plugin table. Please run mysql_upgrade to create it.
InnoDB: The InnoDB memory heap is disabled
InnoDB: Mutexes and rw_locks use InnoDB's own implementation
InnoDB: Compressed tables use zlib 1.2.3
110403 17:29:22  InnoDB: Initializing buffer pool, size = 16.0M
110403 17:29:22  InnoDB: Completed initialization of buffer pool
110403 17:29:22  InnoDB: Operating system error number 13 in a file operation.
InnoDB: The error means mysqld does not have the access rights to
InnoDB: the directory.
InnoDB: File name /opt/lampp/var/mysql/ibdata1
InnoDB: File operation call: 'create'.
InnoDB: Cannot continue operation.
110403 17:29:22 mysqld_safe mysqld from pid file /opt/lampp/var/mysql/ubuntu.pid ended

(Sorry, I don't know how to show terminal messages in an appropiuate way) Can anybody help me on this? Thanks in advance!

Answer 1

I didn't find a certain reason for my problem. I just unisntalled and reinstalled, and then everything went Ok.
That is not a real solution, but it worked. Good luck

Answer 2

I had the same problem with you, and I found some useful information:

2015-08-14 10:51:17 30934 [ERROR] InnoDB: Unable to lock /opt/lampp/var/mysql/ibdata1, error: 11
2015-08-14 10:51:17 30934 [Note] InnoDB: Check that you do not already have another mysqld process using the same InnoDB data or log files.

So, I rebooted the computer and restarted XAMPP, and the problem was resolved.

Answer 3

You can locate the actual socket file and create a symbolic link leading to it as follows:

# check path to socket from mysql settings  
mysqladmin | grep d.sock

# create a symbolic link
ln -s path_to_mysql_socket /opt/lampp/var/mysql/mysql.sock

Answer 4

Although the test you did is a bit garbled, Im going to assume that the test just prove mysql isnt running.

Depending on how the mysql configured itself there should be a startup file somewhere, usually around the /etc/rc.* directories, and you would need to run the rc.mysql start (or it could be a S<nn>MySQL in an rc3.d directory for example

Answer 5

I came in the same situation when I made a grant to *.* to other user. Mysql tried to give permissions over the mysql database and that provoked the disaster: instantly, the mysql.sock file disappeared.

this happened with the version 5.6