我刚刚将 Ubuntu 从 11.10 升级到 12.04。我的 rails 应用程序现在返回 (passenger) 错误“无法通过套接字‘/var/run/mysqld/mysqld.sock’(111) (Mysql2::Error) 连接到本地 MySQL 服务器”。当我尝试使用 mysql -u root -p 在 Ubuntu 服务器上的命令行访问 mysql 时，我收到类似的错误。
我安装了 mysql-server 5.5。我检查了一下，mysql 没有运行。当我尝试重新启动它时，失败了。
以下是尝试重新启动后 /var/log/syslog 末尾的一些关键行：
dean@dgwjasonfried:/etc/mysql$ tail -f /var/log/syslog
Mar 7 08:55:27 dgwjasonfried /etc/mysql/debian-start[5107]: Looking for 'mysqlcheck' as: /usr/bin/mysqlcheck
Mar 7 08:55:27 dgwjasonfried /etc/mysql/debian-start[5107]: Running 'mysqlcheck' with connection arguments: '--port=3306' '--socket=/var/run/mysqld/mysqld.sock' '--host=localhost' '--socket=/var/run/mysqld/mysqld.sock' '--host=localhost' '--socket=/var/run/mysqld/mysqld.sock'
Mar 7 08:55:27 dgwjasonfried /etc/mysql/debian-start[5107]: Running 'mysqlcheck' with connection arguments: '--port=3306' '--socket=/var/run/mysqld/mysqld.sock' '--host=localhost' '--socket=/var/run/mysqld/mysqld.sock' '--host=localhost' '--socket=/var/run/mysqld/mysqld.sock'
Mar 7 08:55:27 dgwjasonfried /etc/mysql/debian-start[5107]: /usr/bin/mysqlcheck: Got error: 2013: Lost connection to MySQL server during query when executing 'CHECK TABLE ... FOR UPGRADE'
Mar 7 08:55:27 dgwjasonfried /etc/mysql/debian-start[5107]: FATAL ERROR: Upgrade failed
Mar 7 08:55:27 dgwjasonfried /etc/mysql/debian-start[5107]: molex_app_development.assets OK
Mar 7 08:55:27 dgwjasonfried /etc/mysql/debian-start[5107]: molex_app_development.ecd_types OK
Mar 7 08:55:27 dgwjasonfried /etc/mysql/debian-start[5124]: Checking for insecure root accounts.
Mar 7 08:55:27 dgwjasonfried kernel: [ 7551.769657] init: mysql main process (5064) terminated with status 1
Mar 7 08:55:27 dgwjasonfried kernel: [ 7551.769697] init: mysql respawning too fast, stopped
/etc/mysql/my.cnf 的大部分内容如下：
Remember to edit /etc/mysql/debian.cnf when changing the socket location.
[client]
port = 3306
socket = /var/run/mysqld/mysqld.sock
Here is entries for some specific programs
The following values assume you have at least 32M ram
This was formally known as [safe_mysqld]. Both versions are currently parsed.
[mysqld_safe]
socket = /var/run/mysqld/mysqld.sock
nice = 0
[mysqld]
Basic Settings
user = mysql
pid-file = /var/run/mysqld/mysqld.pid
socket = /var/run/mysqld/mysqld.sock
port = 3306
basedir = /usr
datadir = /var/lib/mysql
tmpdir = /tmp
lc-messages-dir = /usr/share/mysql
skip-external-locking
Instead of skip-networking the default is now to listen only on
localhost which is more compatible and is not less secure.
bind-address = 127.0.0.1
以下是 var/run/mysqld/mysqld.sock 的权限：
srwxrwxrwx 1 mysql mysql 0 3月 7 09:18 mysqld.sock
我将非常感谢社区提供的任何建议。我查看了此处的相关问题并尝试了一些提供的修复方法，但无济于事。
谢谢！
迪安·理查森
更新：
感谢 quanta 的建议，我查看了 /var/log/mysql/error.log 文件。我发现了与指针、致命信号和更多我实在无法理解的内容相关的错误消息。不过，我还找到了 mysql 手册页参考。有人建议我尝试使用 --innodb_force_recovery=# 选项启动 mysqld，然后尝试转储（或删除）有问题/损坏的数据库或表。
我逐一完成了升级选项级别（innodb_force_recovery=1、innodb_force_recovery=2 等）。这使我能够从命令行成功运行 mysql -u root -p 并执行多个命令。我能够在生产数据库上运行查询，但任何查询、转储甚至删除开发数据库的尝试都会引发错误并导致我失去与 mysql 的连接。
所以我取得了进展，但直到我以某种方式能够删除或修复我的开发数据库时，我仍然无法加载我的应用程序。
还有其他建议或建议吗？
谢谢！
院长
更新：
从命令行运行 sudo mysqld --innodb_force_recover=1 后，error.log 包含以下内容：
重试 sudo mysqld --innodb_force_recover=1 后，error.log 文件显示以下内容：
130308 4:55:39 [Note] Plugin 'FEDERATED' is disabled.
130308 4:55:39 InnoDB: The InnoDB memory heap is disabled
130308 4:55:39 InnoDB: Mutexes and rw_locks use GCC atomic builtins
130308 4:55:39 InnoDB: Compressed tables use zlib 1.2.3.4
130308 4:55:39 InnoDB: Initializing buffer pool, size = 128.0M
130308 4:55:39 InnoDB: Completed initialization of buffer pool
130308 4:55:39 InnoDB: highest supported file format is Barracuda.
InnoDB: The log sequence number in ibdata files does not match
InnoDB: the log sequence number in the ib_logfiles!
130308 4:55:39 InnoDB: Database was not shut down normally!
InnoDB: Starting crash recovery.
InnoDB: Reading tablespace information from the .ibd files...
InnoDB: Restoring possible half-written data pages from the doublewrite
InnoDB: buffer...
130308 4:55:40 InnoDB: Waiting for the background threads to start
130308 4:55:41 InnoDB: 1.1.8 started; log sequence number 10259220
130308 4:55:41 InnoDB: !!! innodb_force_recovery is set to 1 !!!
130308 4:55:41 [Note] Server hostname (bind-address): '127.0.0.1'; port: 3306
130308 4:55:41 [Note] - '127.0.0.1' resolves to '127.0.0.1';
130308 4:55:41 [Note] Server socket created on IP: '127.0.0.1'.
130308 4:55:41 [Note] Event Scheduler: Loaded 0 events
130308 4:55:41 [Note] mysqld: ready for connections.
Version: '5.5.29-0ubuntu0.12.04.2' socket: '/var/run/mysqld/mysqld.sock' port: 3306 (Ubuntu)
然后在 mysql -u root -p 之后
mysql> drop database molex_app_development;
ERROR 2013 (HY000): Lost connection to MySQL server during query
mysql>
error.log 包含：
dean@dgwjasonfried:/var/log/mysql$ tail -f error.log
/lib/x86_64-linux-gnu/libc.so.6(clone+0x6d)[0x7f6a3ff9ecbd]
Trying to get some variables.
Some pointers may be invalid and cause the dump to abort.
Query (7f6a1c004bd8): is an invalid pointer
Connection ID (thread ID): 1
Status: NOT_KILLED
The manual page at http://dev.mysql.com/doc/mysql/en/crashing.html contains
information that should help you find out what is causing the crash.
130308 4:55:39 [Note] Plugin 'FEDERATED' is disabled.
130308 4:55:39 InnoDB: The InnoDB memory heap is disabled
130308 4:55:39 InnoDB: Mutexes and rw_locks use GCC atomic builtins
130308 4:55:39 InnoDB: Compressed tables use zlib 1.2.3.4
130308 4:55:39 InnoDB: Initializing buffer pool, size = 128.0M
130308 4:55:39 InnoDB: Completed initialization of buffer pool
130308 4:55:39 InnoDB: highest supported file format is Barracuda.
InnoDB: The log sequence number in ibdata files does not match
InnoDB: the log sequence number in the ib_logfiles!
130308 4:55:39 InnoDB: Database was not shut down normally!
InnoDB: Starting crash recovery.
InnoDB: Reading tablespace information from the .ibd files...
InnoDB: Restoring possible half-written data pages from the doublewrite
InnoDB: buffer...
130308 4:55:40 InnoDB: Waiting for the background threads to start
130308 4:55:41 InnoDB: 1.1.8 started; log sequence number 10259220
130308 4:55:41 InnoDB: !!! innodb_force_recovery is set to 1 !!!
130308 4:55:41 [Note] Server hostname (bind-address): '127.0.0.1'; port: 3306
130308 4:55:41 [Note] - '127.0.0.1' resolves to '127.0.0.1';
130308 4:55:41 [Note] Server socket created on IP: '127.0.0.1'.
130308 4:55:41 [Note] Event Scheduler: Loaded 0 events
130308 4:55:41 [Note] mysqld: ready for connections.
Version: '5.5.29-0ubuntu0.12.04.2' socket: '/var/run/mysqld/mysqld.sock' port: 3306 (Ubuntu)
130308 4:58:23 [ERROR] Incorrect definition of table mysql.proc: expected column 'comment' at position 15 to have type text, found type char(64).
130308 4:58:23 InnoDB: Assertion failure in thread 140168992810752 in file fsp0fsp.c line 3639
InnoDB: We intentionally generate a memory trap.
InnoDB: Submit a detailed bug report to http://bugs.mysql.com.
InnoDB: If you get repeated assertion failures or crashes, even
InnoDB: immediately after the mysqld startup, there may be
InnoDB: corruption in the InnoDB tablespace. Please refer to
InnoDB: http://dev.mysql.com/doc/refman/5.5/en/forcing-innodb-recovery.html
InnoDB: about forcing recovery.
10:58:23 UTC - mysqld got signal 6 ;
This could be because you hit a bug. It is also possible that this binary
or one of the libraries it was linked against is corrupt, improperly built,
or misconfigured. This error can also be caused by malfunctioning hardware.
We will try our best to scrape up some info that will hopefully help
diagnose the problem, but since we have already crashed,
something is definitely wrong and this may fail.
key_buffer_size=16777216
read_buffer_size=131072
max_used_connections=1
max_threads=151
thread_count=1
connection_count=1
It is possible that mysqld could use up to
key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 346681 K bytes of memory
Hope that's ok; if not, decrease some variables in the equation.
Thread pointer: 0x7f7ba4f6c2f0
Attempting backtrace. You can use the following information to find out
where mysqld died. If you see no messages after this, something went
terribly wrong...
stack_bottom = 7f7ba3065e60 thread_stack 0x30000
mysqld(my_print_stacktrace+0x29)[0x7f7ba3609039]
mysqld(handle_fatal_signal+0x483)[0x7f7ba34cf9c3]
/lib/x86_64-linux-gnu/libpthread.so.0(+0xfcb0)[0x7f7ba2220cb0]
/lib/x86_64-linux-gnu/libc.so.6(gsignal+0x35)[0x7f7ba188c425]
/lib/x86_64-linux-gnu/libc.so.6(abort+0x17b)[0x7f7ba188fb8b]
mysqld(+0x65e0fc)[0x7f7ba37160fc]
mysqld(+0x602be6)[0x7f7ba36babe6]
mysqld(+0x635006)[0x7f7ba36ed006]
mysqld(+0x5d7072)[0x7f7ba368f072]
mysqld(+0x5d7b9c)[0x7f7ba368fb9c]
mysqld(+0x6a3348)[0x7f7ba375b348]
mysqld(+0x6a3887)[0x7f7ba375b887]
mysqld(+0x5c6a86)[0x7f7ba367ea86]
mysqld(+0x5ae3a7)[0x7f7ba36663a7]
mysqld(_Z15ha_delete_tableP3THDP10handlertonPKcS4_S4_b+0x16d)[0x7f7ba34d3ffd]
mysqld(_Z23mysql_rm_table_no_locksP3THDP10TABLE_LISTbbbb+0x568)[0x7f7ba3417f78]
mysqld(_Z11mysql_rm_dbP3THDPcbb+0x8aa)[0x7f7ba339780a]
mysqld(_Z21mysql_execute_commandP3THD+0x394c)[0x7f7ba33b886c]
mysqld(_Z11mysql_parseP3THDPcjP12Parser_state+0x10f)[0x7f7ba33bb28f]
mysqld(_Z16dispatch_command19enum_server_commandP3THDPcj+0x1380)[0x7f7ba33bc6e0]
mysqld(_Z24do_handle_one_connectionP3THD+0x1bd)[0x7f7ba346119d]
mysqld(handle_one_connection+0x50)[0x7f7ba3461200]
/lib/x86_64-linux-gnu/libpthread.so.0(+0x7e9a)[0x7f7ba2218e9a]
/lib/x86_64-linux-gnu/libc.so.6(clone+0x6d)[0x7f7ba1949cbd]
Trying to get some variables.
Some pointers may be invalid and cause the dump to abort.
Query (7f7b7c004b60): is an invalid pointer
Connection ID (thread ID): 1
Status: NOT_KILLED
The manual page at http://dev.mysql.com/doc/mysql/en/crashing.html contains
information that should help you find out what is causing the crash.
- 院长
答案1
让我们以出现的第一个错误作为起点。根据以下信息，它似乎与升级密切相关：
http://forums.mysql.com/read.php?10,503634,503634#msg-503634
尝试运行mysql_upgrade
您还可以使用以下命令检查所有 mysql 数据库表：
myisamchk /var/lib/mysql/mysql/*.MYI
请发布升级前后 mysql 的确切版本
答案2
我建议您从 Oracle mysql 切换到 Percona Mysql Server。
我经常遇到 mysql 和 innodb 问题。percona 团队在他们的 mysql 服务器上做了很多开发修补和性能调优工作。
http://www.percona.com/software/percona-server
您无需触碰 mysql 的数据目录。它无需触碰/修改转换中的数据即可工作。