ERROR! MySQL manager or server PID file could not

问题:

I am having an issue where MySQL isn't starting on my QNAP NAS.

I found this first by not being able to log in through phpMyAdmin - was getting error:

#2002 Cannot log in to the MySQL server

I then went to attempt to start mysql, as I guess this is a common issue with this, but it just gave a generic error.

I went through troubleshooting the mysql.sock file and everything, changing its permissions, but nothing is working.

I have rebooted my NAS many times.

I eventually tried to restart mysql. In doing so I get:

ERROR! MySQL manager or server PID file could not be found!

I can't find anything specific to the QNAP or any general type troubleshooting for this. Everything I find seems to be OSX related.

回答1:

After a lot of searching, I was able to fix the "PID file cannot be found" issue on my machine. I'm on OS X 10.9.3 and installed mysql via Homebrew.

First, I found my PID file here:

/usr/local/var/mysql/{username}.pid

Next, I located my my.cnf file here:

/usr/local/Cellar/mysql/5.6.19/my.cnf

Finally, I added this line to the bottom of my.cnf:

pid-file = /usr/local/var/mysql/{username}.pid

Hopefully this works for someone else, and saves you a headache! Don't forget to replace {username} with your machine's name (jeffs-air-2 in my case).

回答2:

I tried everything above, but saw no results until I got a hint from here: https://superuser.com/questions/159486/how-to-kill-process-in-mac-os-x-and-not-have-it-restart-on-its-own

I eventually went over to the activity monitor in my Mac, force Quit the PID, and ran the command:

sudo /usr/local/mysql/support-files/mysql.server restart

The magic was done!!!

回答3:

If you have installed MySQL using brew the best way to go would be with homebrew

brew services restart mysql

after you run that command, all the problems that the update generated will be resolved

回答4:

I ended up figuring this out on my own.

In searching for my logs I went into

cd /usr/local/mysql/var

In there I found the file named [MyNAS].pid (replace [MyNAS] with the name of your NAS.

I then ran the following to remove the file

rm -rf /usr/local/mysql/var/[MyNAS].pid

I then restarted mysql

[/usr/local/mysql/var] # /etc/init.d/mysqld.sh restart        
/mnt/ext/opt/mysql
/mnt/ext/opt/mysql
Try to shutting down MySQL
ERROR! MySQL manager or server PID file could not be found!
/mnt/ext/opt/mysql
Starting MySQL. SUCCESS! 

I tested everything and it all works like a charm again!

回答5:

Just run mysqld (don't run as root) from your terminal. Your mysql server will restart and reset everything like shown in the picture below:

And use a command like so:

mysql -u root -h 127.0.0.1

回答6:

Run the below commands and it will work.

Go to terminal and type

sudo chown -RL root:mysql /usr/local/mysql

sudo chown -RL mysql:mysql /usr/local/mysql/data

sudo /usr/local/mysql/support-files/mysql.server start

回答7:

I had the same issue. It turns out I added incorrect variables to the my.cnf file. Once I removed them and restarted mysql started with no issue.

回答8:

Check if your server is full first, thats a common reason (can't create the PID file because you have no space). Run this to check your disk usage..

df -h

If you get something like this, you are full..

Filesystem      Size  Used Avail Use% Mounted on
/dev/vda1        40G   40G  6.3M 100% /

In that case, you need to start looking for what to delete to make room, or add an additional drive to your server.

回答9:

ERROR! MySQL server PID file could not be found!

This might be due to issues with disk space, disk inode usage or innodb corruption which may lead to the error.

The issue was with the pid file and the solution was:

1. SSH login to server as a root

2. Create directory /var/run/mysql

mkdir /var/run/mysql

3) Create a file with name as mysqld.pid

touch mysqld.pid

4. Change its ownership and group to mysql:mysql

   chown mysql:mysql mysqld.pid

5. Restart MySQL service

Done!

回答10:

I have the same problem. I found the file {username}.local.err instead {username}.local.pid inside the /usr/local/mysql then i change the name *.err for *.pid and work fine. Starting MySQL SUCCESS!

My OS El Capitan 10.11.5

回答11:

I know this is an older post, but I ran into the ERROR! MySQL server PID file could not be found! when trying to start MySQL after making an update to my.cnf file. I did the following to resolve the issue:

1. Deleted my experimental update to my.cnf

2. Deleted the .net.pid and .net.err files.

delete /usr/local/var/mysql/**<YourUserName>**-MBP.airstreamcomm.net.*

3. Ensured all MySQL processes are stopped.

ps -ax | grep mysql
kill **<process id>**

4. Started MySQL server as normal.

mysql.server start

回答12:

First find PID of mysql service

ps aux | grep mysql

Then, you have to kill process

 sudo kill <pid>

After you again start mysql service

mysql.server start

回答13:

If you're using MySQL Workbench, the mysql.server stop/restart/start will not work.

You will need to login into the workbench and then click "shutdown server". See image attached.

回答14:

I was able to solve this on OS X by shutting down the existing mysql.server that was running:

mysql.server stop

The starting:

mysql.server start

From there I could run mysql.server restart without throwing the ERROR.