maria-discuss team mailing list archive

[Geunsik Lim <leemgs@xxxxxxxxx>]

Recently, I have often been getting the "Error:MySQL server has gone away"
message
after I enabled the multiple-user access in front web service.
Here is logs.

       . . . Upper Omission . . .
2017-04-10 21:15:22.881 [INFO][socketio.js] socket disconnect
2017-04-10 21:15:23.858 [INFO][socketio.js] socket connection
2017-04-10 21:36:07.635 [INFO][socketio.js] socket disconnect
2017-04-10 21:36:16.635 [INFO][socketio.js] socket disconnect
2017-04-10 21:46:12.254 [INFO][socketio.js] socket disconnect
2017-04-10 21:46:12.255 [INFO][socketio.js] socket disconnect
events.js:160
      throw er; // Unhandled 'error' event
      ^

Error: MySQL server has gone away
    at Error (native)


At this time, I have checked the status of mariadb server. Please, see a
time stampe information from the below mariadb's status.
As we can see, the mariadb server was not stopped or not restarted.


root@mytizen:~# systemctl status mysql
* mysql.service - LSB: Start and stop the mysql database server daemon
   Loaded: loaded (/etc/init.d/mysql; bad; vendor preset: enabled)
   Active: active (running) since  2017-04-10 15:35:34 KST; 15h ago
     Docs: man:systemd-sysv-generator(8)
  Process: 1982 ExecStart=/etc/init.d/mysql start (code=exited,
status=0/SUCCESS)
    Tasks: 28
   Memory: 131.6M
      CPU: 29.563s
   CGroup: /system.slice/mysql.service
           ├─2544 /bin/bash /usr/bin/mysqld_safe
           ├─2691 /usr/sbin/mysqld --basedir=/usr --datadir=/var/lib/mysql
--plugin-dir=/usr/lib/mysql/plugin --user=my
           └─2692 logger -t mysqld -p daemon error

 4월 10 15:35:31 mytizen mysqld[2692]: 170410 15:35:31 [Note] InnoDB: 128
rollback segment(s) are active.
 4월 10 15:35:31 mytizen mysqld[2692]: 170410 15:35:31 [Note] InnoDB:
Waiting for purge to start
 4월 10 15:35:31 mytizen mysqld[2692]: 170410 15:35:31 [Note] InnoDB:
 Percona XtraDB (http://www.percona.com) 5.6.34-79
 4월 10 15:35:31 mytizen mysqld[2692]: 170410 15:35:31 [Note] Plugin
'FEEDBACK' is disabled.
 4월 10 15:35:31 mytizen mysqld[2692]: 170410 15:35:31 [Note] Server socket
created on IP: '127.0.0.1'.
 4월 10 15:35:33 mytizen mysqld[2692]: 170410 15:35:33 [Note]
/usr/sbin/mysqld: ready for connections.
 4월 10 15:35:33 mytizen mysqld[2692]: Version:
'10.0.29-MariaDB-0ubuntu0.16.04.1'  socket: '/var/run/mysqld/mysqld.sock
 4월 10 15:35:34 mytizen mysql[1982]:    ...done.
 4월 10 15:35:34 mytizen systemd[1]: Started LSB: Start and stop the mysql
database server daemon.
 4월 10 15:35:34 mytizen mysql[1982]: ERROR 1045 (28000): Access denied for
user 'root'@'localhost' (using password: NO)
root@mytizen:~#
root@mytizen:~#

-------------------

root@mytizen:~# ls -al /var/run/mysqld/mysqld.sock
srwxrwxrwx 1 mysql mysql 0  4 10 15:35 /var/run/mysqld/mysqld.sock

After digging the operation functions  from the mariadb source (
https://github.com/MariaDB/server),
I could get  some hints where the issue was generated.  For example,

a) storage/spider/spd_trx.cc (!conn->disable_reconnect)
https://dev.mysql.com/doc/refman/5.7/en/server-system-variables.html#sysvar_wait_timeout

b) storage/cassandra/ha_cassandra.cc


Anyone who experience a similar issue such as "Error: MySQL server has gone
away" message?




-- 
http://leemgs.fedorapeople.org
Don't try to avoid pain if you fail.
If you decided to face the challenges in life,
you can gain a lot by giving your best.
Cheolsang Jeong's Book & life
--