lower_case_table_names = 2我在文件中设置/etc/my.cnf。我还在/etc/mysql/my.cnf文件中更新了这个变量。设置变量后，我重新启动了 mysql 服务器，但当我使用时，值仍然为 0 SHOW VARIABLES。
我正在使用 MySQL 5.5。还有什么需要做的吗？
更新
my.cnf 内容：-
#
# The MySQL database server configuration file.
#
# You can copy this to one of:
# - "/etc/mysql/my.cnf" to set global options,
# - "~/.my.cnf" to set user-specific options.
#
# One can use all long options that the program supports.
# Run program with --help to get a list of available options and with
# --print-defaults to see which it would actually understand and use.
#
# For explanations see
# http://dev.mysql.com/doc/mysql/en/server-system-variables.html
# This will be passed to all mysql clients
# It has been reported that passwords should be enclosed with ticks/quotes
# escpecially if they contain "#" chars...
# 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
#
lower_case_table_names = 2
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
#
# * Fine Tuning
#
key_buffer = 16M
max_allowed_packet = 16M
thread_stack = 192K
thread_cache_size = 8
# This replaces the startup script and checks MyISAM tables if needed
# the first time they are touched
myisam-recover = BACKUP
#max_connections = 100
#table_cache = 64
#thread_concurrency = 10
#
# * Query Cache Configuration
#
query_cache_limit = 1M
query_cache_size = 16M
#
# * Logging and Replication
#
# Both location gets rotated by the cronjob.
# Be aware that this log type is a performance killer.
# As of 5.1 you can enable the log at runtime!
#general_log_file = /var/log/mysql/mysql.log
#general_log = 1
#
# Error log - should be very few entries.
#
log_error = /var/log/mysql/error.log
#
# Here you can see queries with especially long duration
#log_slow_queries = /var/log/mysql/mysql-slow.log
#long_query_time = 2
#log-queries-not-using-indexes
#
# The following can be used as easy to replay backup logs or for replication.
# note: if you are setting up a replication slave, see README.Debian about
# other settings you may need to change.
#server-id = 1
#log_bin = /var/log/mysql/mysql-bin.log
expire_logs_days = 10
max_binlog_size = 100M
#binlog_do_db = include_database_name
#binlog_ignore_db = include_database_name
#
# * InnoDB
#
# InnoDB is enabled by default with a 10MB datafile in /var/lib/mysql/.
# Read the manual for more InnoDB related options. There are many!
#
# * Security Features
#
# Read the manual, too, if you want chroot!
# chroot = /var/lib/mysql/
#
# For generating SSL certificates I recommend the OpenSSL GUI "tinyca".
#
# ssl-ca=/etc/mysql/cacert.pem
# ssl-cert=/etc/mysql/server-cert.pem
# ssl-key=/etc/mysql/server-key.pem
[mysqldump]
quick
quote-names
max_allowed_packet = 16M
[mysql]
#no-auto-rehash # faster start of mysql but no tab completition
[isamchk]
key_buffer = 16M
#
# * IMPORTANT: Additional settings that can override those from this file!
# The files must end with '.cnf', otherwise they'll be ignored.
#
!includedir /etc/mysql/conf.d/
答案1
正如您在文件中看到的，有多个地方也加载了配置文件。
!includedir /etc/mysql/conf.d/：检查此目录下的每个文件，看设置是否被一个文件覆盖：
grep -i lower_case_table_names /etc/mysql/conf.d/*
或者手动检查文件并搜索配置值。
# - "~/.my.cnf" to set user-specific options.：请检查.my.cnf运行守护进程的用户mysql，也许该设置已被覆盖。
使用以下命令找出用户的 uid：
ps -ef | grep mysql
第一行是 uid。使用以下命令查找用户的主目录：
grep <uid> /etc/passwd
第 6 个:以 分隔的字符串是主目录。当此目录中有 时.my.cnf，将加载此文件。
使用 停止 mysql 守护进程。然后使用和/etc/init.d/mysql stop检查守护进程是否已停止。如果 pgrep 命令仍返回 pid，则使用 终止这些 pid 。有时需要很长时间才能停止大型数据库，这是正常的。因此，在终止之前请先等待。pgrep mysqlpgrep mysqldkillmysql
如果您确定mysql已停止并且所有配置文件都已从该配置值中清除，则mysql重新启动/etc/init.d/mysql start并检查该值。
答案2
对于使用 Windows 和 Workbench 6.1 的用户，以下是我发现的使它工作的方法。选择您的架构并在查询框中输入： set global max_allowed_packet = 1073741824。您可以使用较小的数字，但它必须是 1024 的倍数。这是允许的最大值（1 GB）。执行此操作后，SHOW VARIABLES 不会显示更改 :(，但显然，它确实发生了变化。执行上述语句后立即（可能没有必要）转到 Server/Import。错误“... 9932：MySQL 服务器已消失”不再出现。