Question

When I was writing PHP code with PDO and MySQL, I would always create connections when I needed them within functions like so:

result pseudo_function() {
  create and open connection
  do stuff
  close connection
  return result
}

Now, I started programming in C, I have seen that pointers are an interesting way to pass the entire connection as parameter to the function. I was wondering if it would be better to pass the connections between functions until the entire user request is served.

To clarify: For one user request, there could be 1-5 calls to a function that then opens a database, fetches data, does something, closes and returns.

Also does it make a difference performance wise if you keep a connection opened?

Answer 1

The “standard idiom” for most PHP code I’ve seen seems to be “open the connection, and leave it open”.

php.net seems to be down at the moment, but these two links might be of interest:

• http://php.net/manual/en/function.mysql-pconnect.php

• http://php.net/manual/en/mysqlnd-ms.pooling.php

If you’re running Apache, perhaps mod_dbd might be a good solution:

• http://httpd.apache.org/docs/2.2/mod/mod_dbd.html

Here’s a good discussion on the implications of not closing your connections:

• Is it totally reckless to leave mysql connection open through a page?