[mythtv-users] Why oh why oh why ... mysql suddenly broken

Damian myth at surr.co.uk
Fri Apr 29 12:41:39 UTC 2016 

Hi All,

Well, everything was working fine for about a couple of hours.

Then one of the frontends suddenly couldn't connect to the backend.

Then the frontend on the actual backend system couldn't connect.

Then the backend couldn't connect.

Then I couldn't even connect to mysql, as root or mythtv.

I noticed that there were lots of updates, so I ran them. They seemed to 
be wanting me to reconfigure mysql in some way (talking abut 'MySQL 
administrative account' and 'debian-sys-maint' for some reason).

The problems are still here though (I was hopeful that the updates would 
sort things, but not too hopeful!)

"sudo service mysql status" gives me ...
\u25cf mysql.service - MySQL Community Server
    Loaded: loaded (/lib/systemd/system/mysql.service; enabled; vendor 
preset: enabled)
    Active: activating (start-post) (Result: exit-code) since Fri 
2016-04-29 13:36:41 BST; 15s ago
   Process: 14663 ExecStart=/usr/sbin/mysqld (code=exited, status=1/FAILURE)
   Process: 14659 ExecStartPre=/usr/share/mysql/mysql-systemd-start pre 
(code=exited, status=0/SUCCESS)
  Main PID: 14663 (code=exited, status=1/FAILURE);         : 14664 
(mysql-systemd-s)
     Tasks: 2 (limit: 512)
    CGroup: /system.slice/mysql.service
            \u2514\u2500control
              \u251c\u250014664 /bin/bash 
/usr/share/mysql/mysql-systemd-start post
              \u2514\u250014739 sleep 1

Apr 29 13:36:41 gingerserver systemd[1]: Starting MySQL Community Server...
Apr 29 13:36:43 gingerserver systemd[1]: mysql.service: Main process 
exited, code=exited, status=1/FAILURE


Running "tail -f /var/log/mysql/error.log" in one terminal, and "sudo 
service mysql start" in another gives me ...

Job for mysql.service failed because the control process exited with 
error code. See "systemctl status mysql.service" and "journalctl -xe" 
for details.

... in the first terminal and ...

2016-04-29T12:38:45.431735Z 0 [Note] Shutting down plugin 'MEMORY'
2016-04-29T12:38:45.431747Z 0 [Note] Shutting down plugin 
'PERFORMANCE_SCHEMA'
2016-04-29T12:38:45.431922Z 0 [Note] Shutting down plugin 'MRG_MYISAM'
2016-04-29T12:38:45.431930Z 0 [Note] Shutting down plugin 'MyISAM'
2016-04-29T12:38:45.431959Z 0 [Note] Shutting down plugin 'CSV'
2016-04-29T12:38:45.431969Z 0 [Note] Shutting down plugin 'sha256_password'
2016-04-29T12:38:45.431976Z 0 [Note] Shutting down plugin 
'mysql_native_password'
2016-04-29T12:38:45.432235Z 0 [Note] Shutting down plugin 'binlog'
2016-04-29T12:38:45.432449Z 0 [Note] /usr/sbin/mysqld: Shutdown complete

2016-04-29T12:39:13.767861Z 0 [Warning] Changed limits: max_open_files: 
1024 (requested 5000)
2016-04-29T12:39:13.767955Z 0 [Warning] Changed limits: 
table_open_cache: 457 (requested 2000)
2016-04-29T12:39:14.003323Z 0 [Warning] option 'net_buffer_length': 
unsigned value 8388608 adjusted to 1048576
2016-04-29T12:39:14.003433Z 0 [Warning] TIMESTAMP with implicit DEFAULT 
value is deprecated. Please use --explicit_defaults_for_timestamp server 
option (see documentation for more details).
2016-04-29T12:39:14.004410Z 0 [Note] /usr/sbin/mysqld (mysqld 
5.7.12-0ubuntu1) starting as process 15522 ...
2016-04-29T12:39:14.020515Z 0 [Note] InnoDB: PUNCH HOLE support available
2016-04-29T12:39:14.020666Z 0 [Note] InnoDB: Mutexes and rw_locks use 
GCC atomic builtins
2016-04-29T12:39:14.020705Z 0 [Note] InnoDB: Uses event mutexes
2016-04-29T12:39:14.020746Z 0 [Note] InnoDB: GCC builtin 
__atomic_thread_fence() is used for memory barrier
2016-04-29T12:39:14.020783Z 0 [Note] InnoDB: Compressed tables use zlib 
1.2.8
2016-04-29T12:39:14.020819Z 0 [Note] InnoDB: Using Linux native AIO
2016-04-29T12:39:14.021329Z 0 [Note] InnoDB: Number of pools: 1
2016-04-29T12:39:14.021582Z 0 [Note] InnoDB: Not using CPU crc32 
instructions
2016-04-29T12:39:14.058894Z 0 [Note] InnoDB: Initializing buffer pool, 
total size = 128M, instances = 1, chunk size = 128M
2016-04-29T12:39:14.098798Z 0 [Note] InnoDB: Completed initialization of 
buffer pool
2016-04-29T12:39:14.103250Z 0 [Note] InnoDB: If the mysqld execution 
user is authorized, page cleaner thread priority can be changed. See the 
man page of setpriority().
2016-04-29T12:39:14.215961Z 0 [Note] InnoDB: Highest supported file 
format is Barracuda.
2016-04-29T12:39:14.415294Z 0 [Note] InnoDB: Creating shared tablespace 
for temporary tables
2016-04-29T12:39:14.415567Z 0 [Note] InnoDB: Setting file './ibtmp1' 
size to 12 MB. Physically writing the file full; Please wait ...
2016-04-29T12:39:14.626559Z 0 [Note] InnoDB: File './ibtmp1' size is now 
12 MB.
2016-04-29T12:39:14.628693Z 0 [Note] InnoDB: 96 redo rollback segment(s) 
found. 96 redo rollback segment(s) are active.
2016-04-29T12:39:14.628732Z 0 [Note] InnoDB: 32 non-redo rollback 
segment(s) are active.
2016-04-29T12:39:14.631349Z 0 [Note] InnoDB: Waiting for purge to start
2016-04-29T12:39:14.681788Z 0 [Note] InnoDB: 5.7.12 started; log 
sequence number 12386129
2016-04-29T12:39:14.685628Z 0 [Note] Plugin 'FEDERATED' is disabled.
2016-04-29T12:39:14.687806Z 0 [Note] InnoDB: Loading buffer pool(s) from 
/var/lib/mysql/ib_buffer_pool
2016-04-29T12:39:14.688230Z 0 [Note] InnoDB: Buffer pool(s) load 
completed at 160429 13:39:14
2016-04-29T12:39:14.688831Z 0 [ERROR] unknown variable 'table_cache=128'
2016-04-29T12:39:14.689004Z 0 [ERROR] Aborting

2016-04-29T12:39:14.689118Z 0 [Note] Binlog end
2016-04-29T12:39:14.689309Z 0 [Note] Shutting down plugin 'ngram'
2016-04-29T12:39:14.689417Z 0 [Note] Shutting down plugin 'ARCHIVE'
2016-04-29T12:39:14.689520Z 0 [Note] Shutting down plugin 'partition'
2016-04-29T12:39:14.689622Z 0 [Note] Shutting down plugin 'BLACKHOLE'
2016-04-29T12:39:14.689724Z 0 [Note] Shutting down plugin 
'INNODB_SYS_VIRTUAL'
2016-04-29T12:39:14.689827Z 0 [Note] Shutting down plugin 
'INNODB_SYS_DATAFILES'
2016-04-29T12:39:14.689928Z 0 [Note] Shutting down plugin 
'INNODB_SYS_TABLESPACES'
2016-04-29T12:39:14.690055Z 0 [Note] Shutting down plugin 
'INNODB_SYS_FOREIGN_COLS'
2016-04-29T12:39:14.690156Z 0 [Note] Shutting down plugin 
'INNODB_SYS_FOREIGN'
2016-04-29T12:39:14.690255Z 0 [Note] Shutting down plugin 
'INNODB_SYS_FIELDS'
2016-04-29T12:39:14.690355Z 0 [Note] Shutting down plugin 
'INNODB_SYS_COLUMNS'
2016-04-29T12:39:14.692938Z 0 [Note] Shutting down plugin 
'INNODB_SYS_INDEXES'
2016-04-29T12:39:14.692997Z 0 [Note] Shutting down plugin 
'INNODB_SYS_TABLESTATS'
2016-04-29T12:39:14.693026Z 0 [Note] Shutting down plugin 
'INNODB_SYS_TABLES'
2016-04-29T12:39:14.693054Z 0 [Note] Shutting down plugin 
'INNODB_FT_INDEX_TABLE'
2016-04-29T12:39:14.693081Z 0 [Note] Shutting down plugin 
'INNODB_FT_INDEX_CACHE'
2016-04-29T12:39:14.693108Z 0 [Note] Shutting down plugin 'INNODB_FT_CONFIG'
2016-04-29T12:39:14.693135Z 0 [Note] Shutting down plugin 
'INNODB_FT_BEING_DELETED'
2016-04-29T12:39:14.693162Z 0 [Note] Shutting down plugin 
'INNODB_FT_DELETED'
2016-04-29T12:39:14.693189Z 0 [Note] Shutting down plugin 
'INNODB_FT_DEFAULT_STOPWORD'
2016-04-29T12:39:14.693216Z 0 [Note] Shutting down plugin 'INNODB_METRICS'
2016-04-29T12:39:14.693242Z 0 [Note] Shutting down plugin 
'INNODB_TEMP_TABLE_INFO'
2016-04-29T12:39:14.693269Z 0 [Note] Shutting down plugin 
'INNODB_BUFFER_POOL_STATS'
2016-04-29T12:39:14.693296Z 0 [Note] Shutting down plugin 
'INNODB_BUFFER_PAGE_LRU'
2016-04-29T12:39:14.693323Z 0 [Note] Shutting down plugin 
'INNODB_BUFFER_PAGE'
2016-04-29T12:39:14.693349Z 0 [Note] Shutting down plugin 
'INNODB_CMP_PER_INDEX_RESET'
2016-04-29T12:39:14.693375Z 0 [Note] Shutting down plugin 
'INNODB_CMP_PER_INDEX'
2016-04-29T12:39:14.693402Z 0 [Note] Shutting down plugin 
'INNODB_CMPMEM_RESET'
2016-04-29T12:39:14.693430Z 0 [Note] Shutting down plugin 'INNODB_CMPMEM'
2016-04-29T12:39:14.693456Z 0 [Note] Shutting down plugin 'INNODB_CMP_RESET'
2016-04-29T12:39:14.693482Z 0 [Note] Shutting down plugin 'INNODB_CMP'
2016-04-29T12:39:14.693509Z 0 [Note] Shutting down plugin 
'INNODB_LOCK_WAITS'
2016-04-29T12:39:14.693535Z 0 [Note] Shutting down plugin 'INNODB_LOCKS'
2016-04-29T12:39:14.693561Z 0 [Note] Shutting down plugin 'INNODB_TRX'
2016-04-29T12:39:14.693588Z 0 [Note] Shutting down plugin 'InnoDB'
2016-04-29T12:39:14.693711Z 0 [Note] InnoDB: FTS optimize thread exiting.
2016-04-29T12:39:14.693904Z 0 [Note] InnoDB: Starting shutdown...
2016-04-29T12:39:14.794315Z 0 [Note] InnoDB: Dumping buffer pool(s) to 
/var/lib/mysql/ib_buffer_pool
2016-04-29T12:39:14.794575Z 0 [Note] InnoDB: Buffer pool(s) dump 
completed at 160429 13:39:14
2016-04-29T12:39:16.456235Z 0 [Note] InnoDB: Shutdown completed; log 
sequence number 12386148
2016-04-29T12:39:16.465232Z 0 [Note] InnoDB: Removed temporary 
tablespace data file: "ibtmp1"
2016-04-29T12:39:16.465410Z 0 [Note] Shutting down plugin 'MEMORY'
2016-04-29T12:39:16.465476Z 0 [Note] Shutting down plugin 
'PERFORMANCE_SCHEMA'
2016-04-29T12:39:16.465700Z 0 [Note] Shutting down plugin 'MRG_MYISAM'
2016-04-29T12:39:16.465760Z 0 [Note] Shutting down plugin 'MyISAM'
2016-04-29T12:39:16.465840Z 0 [Note] Shutting down plugin 'CSV'
2016-04-29T12:39:16.465899Z 0 [Note] Shutting down plugin 'sha256_password'
2016-04-29T12:39:16.465954Z 0 [Note] Shutting down plugin 
'mysql_native_password'
2016-04-29T12:39:16.466268Z 0 [Note] Shutting down plugin 'binlog'
2016-04-29T12:39:16.472604Z 0 [Note] /usr/sbin/mysqld: Shutdown complete

Any idea what's going on?

Thanks,
Damian

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