我以前遇到过这样的问题：我的 C 应用程序在 /tmp/mysql.sock 中寻找套接字，但我的套接字位置已设置为 /var/run/mysqld.sock。我现在更改了 my.cnf 中的设置，始终将套接字放入 /tmp。
现在，当我尝试使用 nginx 和 php5-fpm 运行我的 Web 应用程序时，它找不到套接字，因为它仍在 /var/run/mysqld.sock 中查找。起初我创建了一个链接，但后来注意到，每当我重新启动计算机时，该链接就会被删除。
我搜索了 php.ini 并将所有三个（pdo_mysql.default_socket、mysql.default_socket、mysqli.default_socket）可用套接字选项设置为 /tmp/mysql.sock。我在 cgi、cli 和 fpm 文件夹中执行此操作。然而，它仍然不起作用。我还需要添加另一个选项吗？或者我应该重新考虑我的总体方法？
这是我的 php.ini：
[PHP]
engine = On
short_open_tag = On
asp_tags = Off
precision = 14
y2k_compliance = On
output_buffering = 4096
zlib.output_compression = Off
implicit_flush = Off
unserialize_callback_func =
serialize_precision = 100
allow_call_time_pass_reference = Off
s afe_mode = Off
safe_mode_gid = Off
safe_mode_include_dir =
safe_mode_exec_dir =
safe_mode_allowed_env_vars = PHP_
safe_mode_protected_env_vars = LD_LIBRARY_PATH
disable_functions =
disable_classes =
expose_php = On
max_execution_time = 30
max_input_time = 60
memory_limit = 128M
error_reporting = E_ALL & ~E_DEPRECATED
display_errors = Off
display_startup_errors = Off
log_errors = On
log_errors_max_len = 1024
ignore_repeated_errors = Off
ignore_repeated_source = Off
report_memleaks = On
track_errors = Off
html_errors = Off
variables_order = "GPCS"
request_order = "GP"
register_globals = Off
register_long_arrays = Off
register_argc_argv = Off
auto_globals_jit = On
post_max_size = 8M
magic_quotes_gpc = Off
magic_quotes_runtime = Off
magic_quotes_sybase = Off
auto_prepend_file =
auto_append_file =
default_mimetype = "text/html"
doc_root =
user_dir =
enable_dl = Off
file_uploads = On
upload_max_filesize = 2M
max_file_uploads = 20
allow_url_fopen = On
allow_url_include = Off
default_socket_timeout = 60
[Date]
[filter]
[iconv]
[intl]
[sqlite]
[sqlite3]
[Pcre]
[Pdo]
[Pdo_mysql]
pdo_mysql.cache_size = 2000
pdo_mysql.default_socket=/tmp/mysql.sock
[Phar]
[Syslog]
define_syslog_variables = Off
[mail function]
SMTP = localhost
smtp_port = 25
mail.add_x_header = On
[SQL]
sql.safe_mode = Off
[ODBC]
odbc.allow_persistent = On
odbc.check_persistent = On
odbc.max_persistent = -1
odbc.max_links = -1
odbc.defaultlrl = 4096
odbc.defaultbinmode = 1
[Interbase]
ibase.allow_persistent = 1
ibase.max_persistent = -1
ibase.max_links = -1
ibase.timestampformat = "%Y-%m-%d %H:%M:%S"
ibase.dateformat = "%Y-%m-%d"
ibase.timeformat = "%H:%M:%S"
[MySQL]
mysql.allow_local_infile = On
mysql.allow_persistent = On
mysql.cache_size = 2000
mysql.max_persistent = -1
mysql.max_links = -1
mysql.default_port =
mysql.default_socket=/tmp/mysql.sock
mysql.default_host=
mysql.default_user =
mysql.default_password =
mysql.connect_timeout = 60
mysql.trace_mode = Off
[MySQLi]
mysqli.max_persistent = -1
mysqli.allow_persistent = On
mysqli.max_links = -1
mysqli.cache_size = 2000
mysqli.default_port = 3306
mysqli.default_socket =/tmp/mysql.sock
mysqli.default_host =
mysqli.default_user =
mysqli.default_pw =
mysqli.reconnect = Off
[mysqlnd]
mysqlnd.collect_statistics = On
mysqlnd.collect_memory_statistics = Off
[OCI8]
[PostgresSQL]
pgsql.allow_persistent = On
pgsql.auto_reset_persistent = Off
pgsql.max_persistent = -1
pgsql.max_links = -1
pgsql.ignore_notice = 0
pgsql.log_notice = 0
[Sybase-CT]
sybct.allow_persistent = On
sybct.max_persistent = -1
sybct.max_links = -1
sybct.min_server_severity = 10
sybct.min_client_severity = 10
[bcmath]
bcmath.scale = 0
[browscap]
[Session]
session.save_handler = files
session.use_cookies = 1
session.use_only_cookies = 1
session.name = PHPSESSID
session.auto_start = 0
session.cookie_lifetime = 0
session.cookie_path = /
session.cookie_domain =
session.cookie_httponly =
session.serialize_handler = php
session.gc_probability = 1
session.gc_divisor = 1000
session.gc_maxlifetime = 1440
session.bug_compat_42 = Off
session.bug_compat_warn = Off
session.referer_check =
session.entropy_length = 0
session.cache_limiter = nocache
session.cache_expire = 180
session.use_trans_sid = 0
session.hash_function = 0
session.hash_bits_per_character = 5
url_rewriter.tags = "a=href,area=href,frame=src,input=src,form=fakeentry"
[MSSQL]
mssql.allow_persistent = On
mssql.max_persistent = -1
mssql.max_links = -1
mssql.min_error_severity = 10
mssql.min_message_severity = 10
mssql.compatability_mode = Off
mssql.secure_connection = Off
[Assertion]
[COM]
[mbstring]
[gd]
[exif]
[Tidy]
tidy.clean_output = Off
[soap]
soap.wsdl_cache_enabled=1
soap.wsdl_cache_dir="/tmp"
soap.wsdl_cache_ttl=86400
soap.wsdl_cache_limit = 5
[sysvshm]
[ldap]
ldap.max_links = -1
[mcrypt]
[dba]
另外，这是 nginx error.log：
PHP Fatal error: Uncaught exception 'PDOException' with message 'SQLSTATE[HY000] [2002] Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)' in /var/www/php_includes/sfunctions.php:250
以下是我目前通过 PHP 中的 PDO 访问数据库的方式：
$db = new PDO('mysql:host=localhost;dbname=mydb', $dbUser, $dbPass);
