mysql_connect returning "Can't connect to local MySQL server through socket" on remote host connection?

Question

I have a server that's returning an unexpected, intermittent error and wondering if anyone has either experienced it before or can guess what might be going on. My search has so far has been unfruitful.

Im connecting to a remote mysql server using mysql_connect() in the usual way, but for the last 2 weeks (couple of times a day) the connection to the database fails and I get an unable to connect to socket error?

Error: 2002 - Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)

Obviously this is unexpected as Im trying to connect to a remote host. Does mysql_connect default to localhost if the remote host is unavailable? I've not known it to do that, and nothing in the docs that say it does.

There doesn't seem to be any pattern to the failed connections, various files and it happens at all sorts of time of day. Im thinking it might be network traffic related, because if you refresh the page straight away it connects fine, but am confused as to why Im getting an unable to connect to socket error.

the database provider has checked and are unable to find an issue with the server itself. anyone have any ideas?

Answer 1

ok, facepalm moment... after this hitting me for ages I finally found why mysql_error() was reporting the socket error. in my code there was a mysql_select_db() that I didnt notice and it was that, thats reporting the socket error as there is no open connection for it to use.

actual error the mysql_connect is reporting is (2003) Can't connect to MySQL server on 'mysql.hostname.tld'. Im still leaning towards some sort of DNS lookup/network traffic issue, Im currently using the IP address to connect to see if that errors.

But as far as this question is concerned, the answer is "Im a numpty".

Answer 2

Had a similar thing a while back.

Are you connecting from home? The reason I ask is that my ISP likes to mess around re-assinging IP addresses to my home account, and I have an IP authorization on my remote MySQL.

I think I opened up the IP connnection limitation thing to a string that was IP Addresses for my region and that solved the problem.

Answer 3

Have a look at this

Answer 4

If you're running Windows, there might be too many connections already, if so go to http://dev.mysql.com/doc/refman/5.5/en/can-not-connect-to-server.html#can-not-connect-to-server-on-windows and have a read.

Else, perhaps someone someone may have removed the Unix socket file that mysqld uses (/tmp/mysql.sock by default). For example, you might have a cron job that removes old files from the /tmp directory.

Answer 5

Im sure it doesnt default to localhost, and im also pretty sure that it is the remote server sending you the error message. So it's "Local" on your mysql server, not local on "your" server.

In this case its probably due to downtime on the remote server.

Gr.