Performance impact of not closing propel connection

Question

I'm using symfony 1.4/propel 1.4 for a project, which was made by other developer earlier. On that project, propel connection is taken by using following code

$con = Propel::getConnection(UsersPeer::DATABASE_NAME, Propel::CONNECTION_WRITE);

However it never closes the connection using

Propel::close();

I just searched that there are 1500+ such incidents of opening connection & I guess none of them is closing connection.

I know its always good practice to close connection but in present case, it seems I wont be able to fix them all as fixing all the incidents is definitely going to take lot of time, may be a whole day. So now I'm confused if I should fix that or not. If I let it be like that, will it have any performance impact?

EDIT: Just for reference

Part 2 of this question Use of closing database connection in php

Kensell

Do they connect to Propel each time ?! Theorically it's done by Symfony and you don't have to manage the opening/closing. By the way, I guess PHP close the connection at the end of each script if you don't tell it to explicit do it. This usually perform on the __destruct object. See this question/answers. – Nonnah

Not always but mostly in case of transaction operation. However I found few places where it is happening for simple query too. – Kensell

Answer 1

If anything, explicitly closing connections may harm performance. PDO often caches connections from one request to the next, on the reasonable assumption that the next request will use the same credentials.

Edit: reading the docs, it looks to me like PDO::ATTR_PERSISTENT connections are cached regardless of any attempt to close them, so you might as well not bother.

Serum

By first para, does it mean "one should not close the connection" explicitly? If yes, what is the recommended use of Propel::close() – Kensell

IMHO, I don't think you ever really need to call close(). And I wouldn't worry about calling getConnection() over and over again - Propel has it's own connection caching, so you're just getting the same connection back each time. – Serum