How does PHP communicate with MySQL on the same server

Question

Hey!

Does anyone know how php requests data from mysql?

If I have mysql in the same machine as php, does it open a tcp connection to the localhost on port 3306 or does it have some other way of getting the data?

Is it the same in linux and windows?

Thanks

Answer 1

PHP opens a connection to port 3306 is the server via TCP to allow data communication. Hence, you can specify which port to connect to in mysql(i)_connect etc, and why, you need to have firewall rules for mysql.

It is the same in Windows as Linux

So yes, TCP :)

EDIT: Revision, In linux, php looks to connect to mysql via /tmp/mysql.sock the tmp directory needs to have correct permissions.

Answer 2

Usually PHP opens up a local pipe found at /tmp/mysql.sock to connect to a local version of the server, unless you use an IP address in your connection string.

Answer 3

if available it uses a unix socket, otherwise localhost.

Note that even if you specify localhost in the connection string it will try to use the faster "unix socket" if available