Restart mysql keeping the data

Question

I'm quite new using mysql, so let me know if I'm missing something. I took some holidays, and when I got back to work and I tried to log in phpmyadmin I got a ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2).

I never had this problem, so I was browsing to look for a solution. I tried some things, and I'm afraid I touched too much. I couldn't solve the problem, and the I realized that I had some actualizations to be done, and I thought that they may be helpful for mysql. Then I also realized that when I was doing this actualizations first day, they stopped because I had a lack of space, so I restarted then. Then,when the system was configuring mysql, it didn't advance. I waited for a long time and then I just stopped it and restarted the computer. After it, I just tried to uninstall mysql with sudo apt-get remove mysql-server-5.1, and install it again, but it didn't work. Now I have 2 questions:

1. What do you think it is happening? Should I remove mysql completely? What should I do?
2. I'm afraid of losing my databases, is there anyway to recover the data?

Thank you very much in advance.

-----------EDIT-------

These are the messages:

alfonso@alfonso-laptop:/$ tail -F /var/log/syslog | grep 
Feb 15 15:08:01 alfonso-laptop init: mysql post-start process (15192) terminated with status 
Feb 15 15:08:01 alfonso-laptop init: mysql main process (15263) terminated with status 
Feb 15 15:08:01 alfonso-laptop init: mysql main process ended, 
Feb 15 15:08:31 alfonso-laptop init: mysql post-start process (15264) terminated with status 
Feb 15 15:08:31 alfonso-laptop init: mysql main process (15358) terminated with status 
Feb 15 15:08:31 alfonso-laptop init: mysql main process ended, 
Feb 15 15:09:01 alfonso-laptop init: mysql post-start process (15359) terminated with status 
Feb 15 15:09:01 alfonso-laptop init: mysql main process (15447) terminated with status 
Feb 15 15:09:01 alfonso-laptop init: mysql main process ended, 
Feb 15 15:09:32 alfonso-laptop init: mysql post-start process (15448) terminated with status 1

This is the content of error.log-old

110128 13:17:20 [Note] /usr/sbin/mysqld: Normal shutdown

110128 13:17:20 [Note] Event Scheduler: Purging the queue. 0 events
110128 13:17:20  InnoDB: Starting shutdown...
110128 13:17:22  InnoDB: Shutdown completed; log sequence number 0 590872
110128 13:17:22 [Note] /usr/sbin/mysqld: Shutdown complete

110214  2:08:18 [Note] Plugin 'FEDERATED' is disabled.
110214  2:08:19  InnoDB: Started; log sequence number 0 590872
110214  2:08:19 [Note] Event Scheduler: Loaded 0 events
110214  2:08:19 [Note] /usr/sbin/mysqld: ready for connections.
Version: '5.1.41-3ubuntu12.8'  socket: '/var/run/mysqld/mysqld.sock'  port: 3306  (Ubuntu)

--> Some links of similar problems

• https://bugs.launchpad.net/ubuntu/+source/mysql-dfsg-5.1/+bug/573318
• http://www.linuxquestions.org/questions/linux-newbie-8/lamp-install-on-lucid-mysqld-sock-missing-mysql-terminating-status%3D1-853152/

It seems it's a permissions problem... But I don't know which permissions I should change...

SOLVED --> mysql error 2002 "cannot connect to socket"

Answer 1

You could try typing in the command sudo mysqld start in your terminal

Check the host setting, set it to "localhost", otherwise the server isn't reachable when your IP-address changes.

Answer 2

1. Look at the mysql logs to see if there is a specific error. Probably in /var/logs/ somewhere.
2. Your databases are probably in the /var/lib/mysql/ directory. If there are files and directories in there you probably haven't lost anything. First thing I would do is make a copy of everything in that directory to a safe place.

Depending on what you find in the logs you should look at this question on how to recover a failed mysql database.

Answer 3

Normally apt-get remove doesn't remove data nor configuration files (as opposite of purge), if you're on Debian you can find databases file in /var/lib/mysql directory, if this dir is not empty the first thing you should do is to make a backup copy with rsync -av /var/lib/mysql /path/to/backup/. After that you can try to recover your installation.

If you removed the package you should reinstall it and then look into /var/log directory for any error message. You can start a terminal and as root type tail -F /var/log/syslog | grep mysql, after that on another terminal try to start mysql server with /etc/init.d/mysql start and look for error messages in the first window. Then post them here.