I have Debian etch and apache2 and php and mysql. Somehow I messed up mysql. It won't start at boot time. When I type

it says there's no socket at "/var/run/mysqld/mysqld.sock". Is there a way to just create this socket, and is this my problem, or just a symptom? I tried "apt-get remove mysql-server" and then "apt-get install mysql-server" but it didn't make the socket on its own. Any help would be greatly greatly apreciated. Thanks in advance...

Check if the dir /var/run/mysqld exists and is writable by mysql:
Also you can edit my.cnf (/etc/mysql/my.cnf) and change the location of the socket to another dir, for example:either in the [client] and the [mysqld] section.

Regards

I tried setting the permissions on the "/var/run/mysqld" folder. It didn't help. Then I was off to change the location of the socket in the my.cnf file.

I changed the two places it asked for the location of the socket, at [client] and [mysqld], from "/var/run/mysqld/mysqld.sock" to "/tmp/mysqld.sock". No dice. mysql still doesn't work.

I have a question. In the my.cnf file, in the [client] section, it says you should change the debian.cnf file if you change the socket location but the debian.cnf file says not to change the contents (of the debian.cnf file) by hand. It says

Do I touch it anyway? Is there a tool for changing this file? Can I proceed without changing it? Will it help with my problem? When I type "/etc/init.d/mysql start" (as above) I get the following error.

I'm guessing I need to change that debian.cnf file, or there is another place where that socket location is specified. I dont know. Any help would be apreciated.

If the location of mysql.sock is also written in that file you can try to edit it (make a backup first, just in case something goes wrong) and see what happens. If that doesn't work check this to see if it solves your problem.

Regards

I tried changing the debian.cnf file with no good results. I checked out the link you provided (good link, bye the way) and I changed the locations of the mysqld.pid file, but no good results. The error message when I type "/etc/init.d/mysql start" now mentions "/tmp/mysqld.sock" instead of "/var/run/mysqld/mysqld.sock", but nothing else changed.

I was looking at the standard php info page ("phpinfo();" in a php document served by apache2), and there's a section for mysql, even though mysql isn't running. I went to "/etc/php4/apache2/php.ini" and went to the mysql section and specified the location for "mysqld.sock". Then the php info page lists, in two different places, both the old location and the new location for "mysqld.sock".

Where it should show MYSQL_SOCKET under "MySQL support" it shows the old location. Where it should show mysql.default_socket under "directive" it shows the new location. Is there another configuration file somewhere that I'm totally missing?

EDIT: I only noticed now that if I type "/etc/init.d/mysql start" as root, I get an error message that mentions "/tmp/mysqld.sock". If I type "/etc/init.d/mysql start" as normal user, I get an error message that mentions "/var/run/mysqld/mysqld.sock".

I know this is kind of dense and maybe hard to figure out, but I really apreciate the help. Thanks.

You can try to start mysqld either using the mysqld_safe script if your distro uses it (it's available if you install the binary or source from mysql site), or directly using myslqd and see what happens:
Of course you have to change the location of the socket to be the same in all the relevant files.
Another thing to check is, if you have enabled your loopback interface (lo):
Regards

Well here's what happened when I tried "mysqld". Is this helpfull?

"ifconfig -a" seems to return what it should.

Is this helpfull? Also, if I reset the mysql.sock to some new location, what permissions should that new location have?

According to the errors above it seems that after mysql installation you didn't run the "mysql_install_db" script which is used to create the initial mysql database, grant privileges etc. I don't know how you installed mysql, but this must be done before anything else. You can read the postinstallation tasks here. Mind that the location of these files may vary according to your installation method.

Still trouble. Thanks for all your help. I've still got problems. I read the link. I think it was helpfull. I tried the program mysql_install_db. I followed the link. First I erased the folder /var/lib/mysql/mysql so that I could create a new one. Then I typed mysql_install_db as root. I checked and the file had been recreated. Then I typed "mysql_install_db --user=mysql" to initialize the tables. It seemed to go well.

When I try "mysql start" I get the following

When I try "mysqld_safe" I get the following

when I try "mysqld" I get the following

That's everything. Any help would be apreciated. Thanks for all your time so far. I think my mysql database directory was messed up, and the command "mysql_install_db" helped. The socket problem seems to remain, but the error messages seem to have changed. When I read "Do you already have another mysqld server running on port: 3306 ?" I wondered, so I tried phpmyadmin again but no dice.

This means that there is already a mysqld runnig. You can check syslog as suggested by the startup script and also the other log files, specially mysql ones to see if you find out what happens. You can kill the process and try again. Or this is due to the fact that you ran this command (dave@dcl:/etc$ /usr/sbin/mysqld --user=mysql --socket=/tmp/mysql.sock) without being root (note the $ at the prompt)
From my experience with mysql this command is a little tricky. I run it without the "--user=mysql" and then manually change ownership of the datadir. Assuming that yours is /var/lib/mysql/mysql, run:
If you think you have messed up your mysql installation, you can uninstall it and install it again using either your distro's package manager, or the binary from www.mysql.com

Thanks for your help. I reinstalled, and this time I made sure to remove everything related to mysql. I removed or changed all the configuration files, and now mysql works great. Thanks again.