LinuxQuestions.org - [SOLVED] Process ID changing ubruptly while killing mysqld

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Process ID changing ubruptly while killing mysqld

Hi All,

I tried to stop mysqld deamon. It failed

Code:

[zabbix@CDCTGIMCLSA ~]$ sudo /etc/init.d/mysqld stop

Stopping MySQL:                                            [FAILED]

Then I tried to kill the process, but Process Id is getting changed ubruptly.

Code:

[zabbix@CDCTGIMCLSA ~]$ ps -e | grep mysql

 5954 pts/1    00:00:00 mysqld

27338 pts/1    00:00:01 mysqld_safe

[zabbix@CDCTGIMCLSA ~]$ sudo kill -9 5954

kill 5954: No such process

[zabbix@CDCTGIMCLSA ~]$ ps -e | grep mysql

 6155 pts/1    00:00:00 mysqld

27338 pts/1    00:00:02 mysqld_safe

[zabbix@CDCTGIMCLSA ~]$ sudo kill -9 6155

kill 6155: No such process

[zabbix@CDCTGIMCLSA ~]$ ps -e | grep mysql

 6315 pts/1    00:00:00 mysqld

27338 pts/1    00:00:02 mysqld_safe

But following works !!

Code:

sudo kill -9 `pgrep mysqld`

Any reason for this ubrupt changing pid ?

Check if mysqld_safe is the parent

Code:

ps -ef|grep mysql

I don't have Linux system in front of me to check right now.

Thanks for your reply chrism01.

Here mysqld seems to be the parent as mysqld PID 17705 < mysqld_safe PID 23163

Code:

[308718@CDCTGIMCLSB ~]$ sudo /sbin/service mysqld stop

Stopping MySQL:                                            [FAILED]

[308718@CDCTGIMCLSB ~]$ ps -e | grep mysql

17705 ?        00:00:00 mysqld

23163 ?        00:00:06 mysqld_safe

Quote:

Check if mysqld_safe is the parent

chrism01 is right

run pstree | grep mysql and you will find parent and child process

Code:

debian:~# pstree | grep mysql

    |-mysqld_safe-+-logger

    |            `-mysqld---27*[{mysqld}]

if single instant running on server you can user pkill command

Code:

# ps -e | grep mysql

  2837 ?        00:00:00 mysqld_safe

  2874 ?        00:00:11 mysqld

# pkill -15 mysqld

# pkill -15 mysqld_safe

# ps -e | grep mysql

HTH

Thanks sem007,

Here mysqld_safe seems to be the parenet with pstree command

Code:

[zabbix@CDCTGIMCLSA ~]$ sudo pstree | grep mysq

    |-mysqld_safe---mysqld---9*[{mysqld}]

But is it Okay to kill a process with pkill or Kill, when the deamon can't be stopped with

Code:

/etc/init.d/mysqld stop

Here's a thought:

Code:

killall /etc/init.d/mysqld

just run pkill command to kill mysqld

Code:

[root@localhost ~]# ps aux | grep mysql

root      1711  0.0  0.1  4492  1104 pts/3    S    21:46  0:00 /bin/sh /usr/bin/mysqld_safe --datadir=/var/lib/mysql --socket=/var/lib/mysql/mysql.sock --log-error=/var/log/mysqld.log --pid-file=/var/run/mysqld/mysqld.pid --user=mysql

mysql    1767  0.1  1.6 137188 17048 pts/3    Sl  21:46  0:00 /usr/libexec/mysqld --basedir=/usr --datadir=/var/lib/mysql --user=mysql --pid-file=/var/run/mysqld/mysqld.pid --skip-external-locking --socket=/var/lib/mysql/mysql.sock

root      1798  0.0  0.0  3920  660 pts/3    R+  21:48  0:00 grep mysql





[root@localhost ~]# pkill -9 mysqld





[root@localhost ~]# ps aux | grep mysql

root      1802  0.0  0.0  3920  656 pts/3    S+  21:48  0:00 grep mysql



[root@localhost ~]#

@ Kenny_Strawn

Quote:

Code:

killall /etc/init.d/mysqld

it gives me error

Code:

[root@localhost ~]# ps -e | grep mysql

 1849 pts/3    00:00:00 mysqld_safe

 1909 pts/3    00:00:00 mysqld



[root@localhost ~]# killall /etc/init.d/mysqld

/etc/init.d/mysqld: no process killed



[root@localhost ~]#

[EDIT]

when i run below command it works

killall mysqld

@sem007,

Yeah I got it how this pkill works. But my question is, does killing a process with pkill or kill cause abrupt deamon stop ?

Is it the step taken when the deamon fails to stop ?

@ Kenny_Strawn

This gives error..

Code:

[root@localhost ~]# killall /etc/init.d/mysqld

/etc/init.d/mysqld: no process killed

[root@localhost ~]#

Quote:

Yeah I got it how this pkill works. But my question is, does killing a process with pkill or kill cause abrupt deamon stop ?

Is it the step taken when the deamon fails to stop ?

when you stop service it will use kill command to terminate process.

some lines from /etc/init.d/mysqld script

Code:

stop(){

        MYSQLPID=`cat "$mypidfile"  2>/dev/null `

        if [ -n "$MYSQLPID" ]; then

            /bin/kill "$MYSQLPID" >/dev/null 2>&1

I advise use signal 15 (TERM) when you kill process.

HTH

You should use ps -ef (full format) instead of ps -e. I'm pretty sure you will recognize that: mysqld_safe is parent process of mysqld:

Code:

# ps -ef | grep mysqld

root      2657    1  0 Jun13 ?        00:00:00 /bin/sh /usr/bin/mysqld_safe --datadir=/var/lib/mysql --socket=/var/lib/mysql/mysql.sock --log-error=/var/log/mysqld.log --pid-file=/var/run/mysqld/mysqld.pid --user=mysql

mysql    2707  2657  0 Jun13 ?        03:19:36 /usr/libexec/mysqld --basedir=/usr --datadir=/var/lib/mysql --user=mysql --pid-file=/var/run/mysqld/mysqld.pid --skip-external-locking --socket=/var/lib/mysql/mysql.sock

Exactly, the relative values of the pids is irrelevant, the system pids wrap around after 4 digits...

@quanta, @chrism01, @sem007
Thank you for your advices.