mysql_connect vs. mysql_pconnect

[Son Nguyen]

My understanding is that if the script has to connect to the DB quite often, using pconnect() should be more appropriate.
Does mysql_pconnnect() differentiate between connections from this or another machine? Since in the documetation, it said it finds some connection already made, but does that connection have to be from the same client or same script?
Thanks

[Kevin Yank]

mysql_pconnect() does not differentiate between connections based on the client IP or any other information. All it does is create a connection to the MySQL server that will not be closed when the script terminates, so the next time a script calls mysql_pconnect() with the same arguments (MySQL server, username, password), the existing connection will be used instead of a new one being created.

Doesn't matter what script or client is using the connection.

[Son Nguyen]

Thanks a lot Kevin,
I think I did recognize the difference in performance when I change that

[mad-onion]

A question for Kevin on this issue..

Is it more intensive on server resources to use p_connect or is it possibly the complete opposite?
I have never used this, even knowing what it did, because i never really understood what the positve/negatives are of persistant connections...could you enlightne me?

TIA

[Kevin Yank]

Using mysql_pconnect() will save PHP the trouble of opening a new connection to your MySQL server to service every client request, so in that sense it definitely saves time. So if you consider time a server resource, then it definitely saves resources.

There aren't any real downsides to using persistent connections, except that they will not work on the CGI version of PHP. Since a new PHP process is created for every client request, the MySQL connection dies with the PHP process at the end of the request.

[mad-onion]

Thanks for that Kevin.

You are a legend!