Mysqli cannot use localhost. What is the problem?

The Code is as follows: {code ...} if the connection address is & #039; localhost & #039;, an error is reported, as follows: Warning: mysqli () :( HY0002002): Nosuchfileordirectoryinmntwwwcglevipublichtmlmysql. phponline2ConnectError... the Code is as follows:

  connect_error) {    die('Connect Error (' . $mysqli->connect_errno . ') '            . $mysqli->connect_error);};echo 'ok';

• If the above connection address is 'localhost', an error is reported, as follows:

  Warning: mysqli (): (HY000/2002): No such file or directory in/mnt/www/cgLevi/publicHtml/mysql. php on line 2 Connect Error (2002) No such file or directory

• After changing 'localhost' to '192. 0.0.1 ', the link is normal.

Check the hosts, as shown below:

127.0.0.1 localhost::1         localhost localhost.localdomain localhost6 localhost6.localdomain6/etc/hosts (END) 

Check the mysql status as follows:

mysql> status;--------------mysql  Ver 14.14 Distrib 5.6.10, for Linux (x86_64) using  EditLine wrapperConnection id:      860Current database:   Current user:       root@localhostSSL:            Not in useCurrent pager:      stdoutUsing outfile:      ''Using delimiter:    ;Server version:     5.6.10 MySQL Community Server (GPL)Protocol version:   10Connection:     Localhost via UNIX socketServer characterset:    latin1Db     characterset:    latin1Client characterset:    utf8Conn.  characterset:    utf8UNIX socket:        /var/lib/mysql/mysql.sockUptime:         13 hours 13 min 50 secThreads: 1  Questions: 11900  Slow queries: 0  Opens: 100  Flush tables: 1  Open tables: 80  Queries per second avg: 0.249--------------

How can this problem be solved?

Reply content:

The Code is as follows:

  connect_error) {    die('Connect Error (' . $mysqli->connect_errno . ') '            . $mysqli->connect_error);};echo 'ok';

• If the above connection address is 'localhost', an error is reported, as follows:

  Warning: mysqli (): (HY000/2002): No such file or directory in/mnt/www/cgLevi/publicHtml/mysql. php on line 2 Connect Error (2002) No such file or directory

• After changing 'localhost' to '192. 0.0.1 ', the link is normal.

Check the hosts, as shown below:

127.0.0.1 localhost::1         localhost localhost.localdomain localhost6 localhost6.localdomain6/etc/hosts (END) 

Check the mysql status as follows:

mysql> status;--------------mysql  Ver 14.14 Distrib 5.6.10, for Linux (x86_64) using  EditLine wrapperConnection id:      860Current database:   Current user:       root@localhostSSL:            Not in useCurrent pager:      stdoutUsing outfile:      ''Using delimiter:    ;Server version:     5.6.10 MySQL Community Server (GPL)Protocol version:   10Connection:     Localhost via UNIX socketServer characterset:    latin1Db     characterset:    latin1Client characterset:    utf8Conn.  characterset:    utf8UNIX socket:        /var/lib/mysql/mysql.sockUptime:         13 hours 13 min 50 secThreads: 1  Questions: 11900  Slow queries: 0  Opens: 100  Flush tables: 1  Open tables: 80  Queries per second avg: 0.249--------------

How can this problem be solved?

The initial answer was a little less rigorous and it was estimated that the problem had not been solved. The answer was changed:

Cause:

When the host is set to localhost, MySQL uses unix domain socket connection. When the host is set to 127.0.0.1, MySQL uses TCP/IP connection. Unix socket connections are faster and safer than TCP/IP connections. This is a feature of MySQL connection. For more information, see 4.2.2. Connecting to the MySQL Server:

On Unix, MySQL programs treat the host name localhost specially, in a way that is likely different from what you expect compared to other network-based programs. For connections to localhost, MySQL programs attempt to connect to the local server by using a Unix socket file. This occurs even if a --port or -P option is given to specify a port number. To ensure that the client makes a TCP/IP connection to the local server, use --host or -h to specify a host name value of 127.0.0.1, or the IP address or name of the local server. You can also specify the connection protocol explicitly, even for localhost, by using the --protocol=TCP option.

There are several solutions to this problem:

1. Use TCP/IP instead of Unix socket. Replace localhost with 127.0.0.1 during connection.

2. Modify MySQL configuration file my. cnf and specify the location of mysql. socket:

   /Var/lib/mysql. sock (your mysql. socket path ).

3. Directly specify the location of my. socket when establishing a connection in php (Official Document: mysqli_connect ). For example:

   $ Db = new MySQLi ('localhost', 'root', 'root', 'My _ db', '123', '/var/run/mysqld. sock ')

If you haven't made it clear or wrong, please submit it ~~

Refer to this question: http://segmentfault.com/q/1010000000320989

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