Error mysql server pid file could not be found

Hello everyone, I have one problem of my MySQL database. I am getting an error in the database stated “MySQL is running but PID file could not be found” and I have tried several process to fix it. Even I have tried to shutdown mysqladmin which also does not work. Finally I have to kill the process ID and I was lucky enough that my database is safe and it did not cause any issue. But still I am confused what to do and not getting any option to solve it. What to do, can anyone help me?

Well MySQL is one of the useful database which is used by many organization and it is a database software in the application world. It is used for many purpose and sometimes users has to work with its services and then restart the services for the changes which is made to see the effect. But while starting MySQL service, an error may occur which can disturb the entire database. The error states:

MySQL is running but PID file could not be found

This issue can be due to several unwanted things and even due to disk space, innodb corruption or may be disk inode.

Here the issue is with PID file and solution is mentioned:

SSH server as a root user

Then create a directory /var/run/mysql

Now create a file named as mysqld.pid

Then change its ownership and group to mysql:mysql

chown mysql:mysql mysqld.pid

At last restart the MySQL service and no errors will be seen.

If you are not satisfied with this process then you have to completely kill the process Id. For that you have to follow the steps provided:

First check whether /tmp partition is full. This happens when MySQL cannot write the /tmp partition to create a lock file.

Even there is a possibility that the /tmp partition is cleared and MySQL server is looking for PID file there. Therefore just create a new PID file and again restart the server.

By doing this the status is checked, even sometimes you can get an error message like:

ERROR! MySQL is not running, but lock file (/var/lock/subsys/mysql) exists

Well this may be an instance, just remove the lock file and then restart the server.

rm /var/lock/subsys/mysql

When this does not work then you have to kill the current MySQL process from server by below mentioned steps:

With process ID you can get all process of MySQL. You need to kill PID for MySQL by the following command

At last restart MySQL service

The above steps mentioned are the ways to repair error! MySQL is not running, but PID file exists and this should be followed properly.

Automatic Way to Repair “MySQL Is Running But PID File Could Not Be Found”

After trying the above mentioned steps if still you are facing the same issue then you need to use third party tool like MySQL file Repair Tool which is one of the best tool for repairing MySQL database. It completely works to fix any type of error in MySQL and recovers the entire database.

This software can also save the retrieved information in Transact-SQL script which is fit for quick database recreation. And also it recovers table structure and data. It supports MySQL versions like 5.x, 4.x, 3.x, 2.x and 1.x and available for all modern platforms that includes windows 95/98/2000/XP/2003 server.

It has the ability to repair password protected SQL files smoothly. And most importantly it is very user friendly. So, you need to download this excellent program and follow its easy steps to fix error! MySQL server PID file could not be found! with ease.

Steps to repair corrupted MySQL table

Step 1: Start with Stellar Phoenix Database Repair for MySQL . Software and you can see the main interface as shown below.

Step 2: Click on ‘Select’ button & then select ‘Repair corrupt database which is stored at default location of MySQL’ option to select your database from default location and then click.

Step 3: The left pane shows the preview of database and its component in a tree like structure after completing scanning process.

Step 4: After previewing your database, to start repair process click ‘Repair’ button in file menu on the main user interface. Stellar Phoenix Database Repair for MySQL dialog box appears. Click Yes.

Step 5: After successful completion of the process, a message box is displayed as ‘repair process finished successfully’. Click ‘OK’ to close the message box.

Step 6: If you want to select the database manually then select ‘Manual selection of database to repair’ option & then click browse. Browse the folder dialog box opens. Select the folder that contains database and click ‘OK’.

Time To Conclude

I Hope, the aforementioned methods will help you to resolve ‘MySQL is running but PID file could not be found’ error and recovers table structure & data with ease. but if you want instant resolution to fix this error then you can try MySQL Repair Tool. This program will definitely allow you to repair your MySQL database and get back all the database in a hassle free manner.

Therefore, all the very best to you………

The MySql server PID file could not be found error occurs when MySQL cannot find the PID file. It may also occur if the MySQL process is killed abruptly. Since the process does not end properly, the PID file is mismatched.

Solution

Step 1. Check for the parameter PID-file and create /var/run/mysqld/

Check where your PID-file points to. You can do this by running:

my.cnf

If the parameter is not present, set it as shown below:

pid-file    = /var/run/mysqld/mysqld.pid

Next, create the following directory and give it the appropriate permissions, as follows:

mkdir /var/run/mysqld
touch /var/run/mysqld/mysqld.pid
chown -R mysql:mysql /var/run/mysqld

Step 2. Change ownership of the MySQL folder

Change the ownership of the MySQL folder:

sudo chown -R _mysql:_mysql mysql

Step 3. Change permissions of the MySQL folder

You can change the permissions of the MySQL folder by typing:

sudo chmod 777 /usr/local/var/mysql

Change permissions of /usr/local/var

If the above solutions do not work, try changing the permissions of /usr/local/var by typing:

sudo chmod 777 /usr/local/var

Getting frustrated with MySQL PID could not be found CentOS error?

This is a common problem that happens when we simply restart the MySQL server.

Also, the error is due to the existing PID doesn’t allow us to create a new PID.

At Bobcares, we often get requests to solve such MySQL errors as part of our Server Management Services.

Today, let’s analyze the causes and see how our Support Team fix it for our customers.

What is MySQL PID could not be found CentOS error?

Let’s first get an idea of the error as such. In any server, Process identifier, a PID is a unique number that identifies each running process. Every service running on the server will have a unique PID associated with it.

The MYSQL PID error occurs due to existing PID doesn’t allow to create new PID. So we kill the old PID and restart the MYSQL service. Usually, this error arises when we try to restart the MYSQL service.

Recently one of our customers contacted us with the MYSQL PID error. He tried to restart the MYSQL service and it returned the error as:

How we fix MySQL PID could not be found centos error?

So far, we discussed MySQL PID could not be found centos error. Now let’s see how our Support Engineers fix this error for our customers.

Solution 1

To fix this error Our Support Engineers follow the below steps.

Normally, the reason for the error is due to the existing PID not allowing us to create a new PID. So we kill the old PID and then start MySQL service.

1. Therefore, we first check the MySQL existing PID.  So we use the below command.

ps -aufx | grep mysql

Normally, the sample result will appear like this,

[root@server ~]# ps -aufx | grep mysql
root 10075 0.0 0.0 61304 748 pts/0 S+ 00:31 0:00 _ grep mysql
mysql 4745 0.0 0.0 65948 1312 ? S Mar13 0:00 /bin/sh /usr/bin/mysqld_safe --datadir=/var/lib/mysql --pid-file=/var/lib/mysql/cent.pid
mysql 3546 0.0 2.1 288868 85376 ? Sl Mar13 198:35 _ /usr/sbin/mysqld --basedir=/ --datadir=/var/lib/mysql --user=mysql --log-error=/var/lib/mysql/cent .err --pid-file=/var/lib/mysql/cent.pid

From this above result, we found two existing MYSQL PIDs. And follow the steps.

2. Next, we kill the process using the below command.

[root@server ~]# kill -9 4745

[root@server ~]# kill -9 3546

3. Then we start MySQL service.

[root@server ~]# /etc/init.d/mysqld start
Starting MySQL...... SUCCESS!

4. Next, we check the MySQL service Status.

[root@server ~]# /etc/init.d/mysqld status
SUCCESS! MySQL running (14346)
[root@server ~]#

The MySQL service has been restarted successfully

Solution 2

Sometimes, the 100% usage of a server partition also can cause an error. Here, we check for the /tmp partition is full or not. Also, this can happen when MySQL can’t write to the /tmp partition to create a lock file.

1. For that, we use the below command to check the storage of partition.

$ df -h

Also, in many cases, clearing the /tmp partition results in failure to fetch the MySQL PID file. So we just create the PID file and restart the service.

2. Therefore, we use the below command to create the PID file. After that, we restart the MYSQL service.

$ touch /tmp/mysql.sock

$ service mysqld restart

3. Next, we check the MYSQL status.

service mysqld status
ERROR! MySQL is not running, but lock file (/var/lock/subsys/mysql) exists

Similarly, when the error is with the lock file, we remove the lock file and restart the MYSQL service.

$rm /var/lock/subsys/mysql
$ service mysqld restart

4. Again, if we get an error like this:

$ service mysqld restart
ERROR! MySQL server PID file could not be found!
Starting MySQL. ERROR! The server quit without updating PID file (/var/lib/mysql/mydomain.com.pid).

5. Then we check the log file:/var/lib/mysql/mydomain.com.err

$ tail /var/lib/mysql/mydomain.com.err
130506 14:44:07 mysqld_safe mysqld from pid file /var/lib/mysql/mydomain.com.pid ended

Here the error tells us that we have a compatibility problem with some of our tables and MySQL fails to start in safe mode.

6. Therefore, we change the way MySQL starts to work around this situation.

$ { echo “mysql_enable=”YES””; echo “mysql_args=”–skip-grant-tables –skip-networking””; } >> /etc/init/rc.conf

7. Again we start the MYSQL service successfully.

8. Then after, we try to upgrade the MYSQL service.

$ mysql_upgrade

[Need more assistance for MySQL PID could not be found CentOS error? We are available 24×7 to fix it for you.]

Conclusion

In short, the MySQL PID could not be found CentOS error occurs due to the existing PID not allowing us to create a new PID. Also, it is a common problem during the restart of the MYSQL server. Today, we saw how our Support Engineers fix this error.

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Related Article — MySQL Error

Display Errors Using MySQLi Error Functions

Starting and stopping the MySQL server via Preferences Pane/launchd and on the other hand via sudo /usr/local/mysql/support-files/mysql.server start/stop are not really compatible.

After choosing «Launchd Support» in the MySQL installer the launch daemon com.oracle.oss.mysql.mysqld will be created and the MySQL preferences pane uses the launchd mechanism to start and stop mysql. If you enable «Automatically Start MySQL Server on startup», mysqld is enabled automatically after starting your Mac.

The pid file’s name created by the launch daemon is not compatible with the one created and expected by the mysql-server script.

The launch daemon’s pid file name created while running is mysql.local.pid, the script expects a name based on your Mac’s hostname, .local or computer name though.

So either use the MySQL pref pane/launchctl or the script to start and stop mysqld.

To some extent you can make both methods compatible by modifying the file com.oracle.oss.mysql.mysqld though:

After stopping mysql replace the array

<array>
    <string>/usr/local/mysql/bin/mysqld</string>
    <string>--user=_mysql</string>
    <string>--basedir=/usr/local/mysql</string>
    <string>--datadir=/usr/local/mysql/data</string>
    <string>--plugin-dir=/usr/local/mysql/lib/plugin</string>
    <string>--log-error=/usr/local/mysql/data/mysql.local.err</string>
    <string>--pid-file=/usr/local/mysql/data/mysql.local.pid</string>
</array>

by

<array>
    <string>/usr/local/mysql/bin/mysqld</string>
    <string>--user=_mysql</string>
    <string>--basedir=/usr/local/mysql</string>
    <string>--datadir=/usr/local/mysql/data</string>
    <string>--plugin-dir=/usr/local/mysql/lib/plugin</string>
    <string>--log-error=/usr/local/mysql/data/$name.err</string>
    <string>--pid-file=/usr/local/mysql/data/$name.pid</string>
</array>

with $name: either HostName (e.g. host.example.com), LocalHostName (e.g. host.local) or ComputerName (e.g. host). Probably the best is to use a hostname. You may get a hostname with hostname with scutil --get HostName or set it with sudo scutil --set HostName your_hostname.

You can also get the actually used mysql-server script pid’s name — after stopping the launch daemon and starting mysqld with mysql-server start— by checking mysql’s data directory with sudo ls /usr/local/mysql/data. Use the name found there to adjust the plist’s pid name.

You may have to convert the launch daemon file to xml to edit it. The app TextWrangler opens it as xml file immediately.

Reload the plist with launchctl afterwards.

Now should be able to start and stop with the MySQL pref pane and the mysql.server script.

If you have enabled «Automatically Start MySQL Server on Startup», you can’t stop the server – even after modifying the plist – with the script because launchd overrides any stop command after a few seconds and launches mysqld again.