我正在尝试修改Ubuntu 12.04中的my.cnf文件来微调mysql。我复制粘贴使用此工具https://tools.percona.com/wizard
这确实加速了mysql但是当我尝试通过CLI访问mysql时，我收到以下错误：
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (13)
我替换旧的my.cnf文件后，一切都恢复正常。这是我的原始文件：
#
# 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
#
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/
这是我的新文件，任何人都可以帮助我，看看为什么我在文件更新后出现此错误？感谢
# Generated by Percona Configuration Wizard (http://tools.percona.com/) version REL5-20120208
[mysql]
# CLIENT #
port = 3306
socket = /var/lib/mysql/mysql.sock
[mysqld]
# GENERAL #
user = mysql
default-storage-engine = InnoDB
socket = /var/lib/mysql/mysql.sock
pid-file = /var/lib/mysql/mysql.pid
# MyISAM #
key-buffer-size = 32M
myisam-recover = FORCE,BACKUP
# SAFETY #
max-allowed-packet = 16M
max-connect-errors = 1000000
# DATA STORAGE #
datadir = /var/lib/mysql/
# BINARY LOGGING #
log-bin = /var/lib/mysql/mysql-bin
expire-logs-days = 14
sync-binlog = 1
# CACHES AND LIMITS #
tmp-table-size = 32M
max-heap-table-size = 32M
query-cache-type = 0
query-cache-size = 0
max-connections = 500
thread-cache-size = 50
open-files-limit = 65535
table-definition-cache = 1024
table-open-cache = 2048
# INNODB #
innodb-flush-method = O_DIRECT
innodb-log-files-in-group = 2
innodb-log-file-size = 256M
innodb-flush-log-at-trx-commit = 1
innodb-file-per-table = 1
innodb-buffer-pool-size = 6G
# LOGGING #
log-error = /var/lib/mysql/mysql-error.log
log-queries-not-using-indexes = 1
slow-query-log = 1
slow-query-log-file = /var/lib/mysql/mysql-slow.log
答案 0 :(得分：2)
最简单的方法是将对已更改路径 /var/lib/mysql/mysql.sock 的所有引用重置为其原始值，即 / var / run / mysqld / mysqld .sock 。用 /var/run/mysqld/mysqld.pid 替换 /var/lib/mysql/mysql.pid 也是如此。然后通过 /var/log/mysql/error.log 和 / var / lib / mysql更改对 /var/lib/mysql/error.log 的引用/mysql-slow.log 到 /var/log/mysql/mysql-slow.log
<强>替代
或者，您可以将“client”部分添加回新配置文件中，然后更新其值以匹配新配置文件的“mysqld”部分中定义的值（即 / var / lib /mysql/mysqld.sock）。
[client]
socket = /var/lib/mysql/mysql.sock
然后，您必须确保此目录存在，并且可由用户 mysql 写入。
答案 1 :(得分：2)
这是一个完整的替换文件。
[client]
port = 3306
socket= /var/run/mysqld/mysqld.sock
[mysqld_safe]
socket= /var/run/mysqld/mysqld.sock
nice = 0
[mysqld]
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
bind-address = 127.0.0.1
key_buffer= 16M
max_allowed_packet = 16M
thread_stack = 192K
thread_cache_size = 8
myisam-recover= BACKUP
query_cache_limit= 1M
query_cache_size = 16M
log_error = /var/log/mysql/error.log
expire_logs_days = 10
max_binlog_size= 100M
###### Additions #######
default-storage-engine= InnoDB
key-buffer-size = 32M
myisam-recover = FORCE,BACKUP
max-allowed-packet = 16M
max-connect-errors = 1000000
log-bin= /var/lib/mysql/mysql-bin
expire-logs-days= 14
sync-binlog = 1
tmp-table-size = 32M
max-heap-table-size= 32M
query-cache-type= 0
query-cache-size= 0
max-connections = 500
thread-cache-size = 50
open-files-limit= 65535
table-definition-cache= 1024
table-open-cache= 2048
innodb-flush-method= O_DIRECT
innodb-log-files-in-group= 2
innodb-log-file-size = 256M
innodb-flush-log-at-trx-commit = 1
innodb-file-per-table = 1
innodb-buffer-pool-size = 6G
log-queries-not-using-indexes = 1
slow-query-log = 1
slow-query-log-file= /var/log/mysql/mysql-slow.log
[mysqldump]
quick
quote-names
max_allowed_packet = 16M
[mysql]
port= 3306
socket = /var/run/mysqld/mysqld.sock
[isamchk]
key_buffer= 16M
!includedir /etc/mysql/conf.d/