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strace 解決 mysql 連接配接資料庫總是定位/tmp/mysql.sock的問題

檢視mysqld和mysql預設讀取my.cnf的順序

···

mysql --help --verbose | grep 'my.cnf'

order of preference, my.cnf, $MYSQL_TCP_PORT,

/etc/my.cnf /etc/mysql/my.cnf /usr/local/mysql/etc/my.cnf ~/.my.cnf

mysqld --verbose --help | grep 'my.cnf'

/etc/my.cnf /etc/mysql/my.cnf /usr/local/mysql/etc/my.cnf ~/.my.cnf

my.cnf, $MYSQL_TCP_PORT, /etc/services, built-in default

報錯的表現

mysql

ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2)

stace mysql 指令的執行過程

strace /usr/local/mysql/bin/mysql

execve("/usr/local/mysql/bin/mysql", ["/usr/local/mysql/bin/mysql"], [/ 21 vars /]) = 0

= 0

stat("/etc/my.cnf", 0x7ffca8678640) = -1 ENOENT (No such file or directory)

stat("/etc/mysql/my.cnf", 0x7ffca8678640) = -1 ENOENT (No such file or directory)

stat("/usr/local/mysql/etc/my.cnf", {st_mode=S_IFREG|0644, st_size=3816, ...}) = 0

open("/usr/local/mysql/etc/my.cnf", O_RDONLY) = 3

fstat(3, {st_mode=S_IFREG|0644, st_size=3816, ...}) = 0

mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fb9595ef000

read(3, "# For advice on how to change se"..., 4096) = 3816

read(3, "", 4096) = 0

close(3) = 0

munmap(0x7fb9595ef000, 4096) = 0

stat("/root/.my.cnf", 0x7ffca8678640) = -1 ENOENT (No such file or directory)

stat("/root/.mylogin.cnf", {st_mode=S_IFREG|0600, st_size=504, ...}) = 0

open("/root/.mylogin.cnf", O_RDONLY) = 3

删除.mylogin.cnf檔案

rm /root/.mylogin.cnf

rm: remove regular file ‘/root/.mylogin.cnf’? y

再次登入正常

#mysql

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