Question

I am making a simple blog for myself and while reading through the PHP manual, I found this https://www.php.net/manual/en/function.pg-query.php

It says

resource pg_query ([ resource
$connection ], string $query )

…

Note: Although connection can be omitted, it is not recommended, since
it can be the cause of hard to find
bugs in scripts.

Why is it not ok to just use the last connection? I never plan on having more than 1 connection open per PHP script, so how would this ever cause bugs for me?

Answer 1

Hah. “I never plan on having more than 1 connection open per PHP script.”

I remember the last time I said that. It was back in ‘ought three. I was a young whippersnapper then, much like yourself. Full of spit and vinegar. Why do something if I don’t have to? That was the prevailing wisdom in our little dot-com startup. “Just get it done!” we’d shout. Also, we wore onions on our belts.

Well… time came that I added a quick little statistics database in to the main site. Nothing special, just wanted some stats tracked separately. I figured I’d re-use the database wrapper. It was a good wrapper for it’s time! Abstracted out all the database functions I’d need. But as soon as I added it in there, some wacky things started happening. It didn’t make sense. I had two separate database wrapper objects… two separate connections! How could they affect each other? But then users would be logged out randomly. Sessions would fail. Sometimes a key update would go bad. Some queries ran on the wrong databases. Dogs and cats started living together! It was mass hysteria!

If only I had specified that connector originally. If only I had kept them specific, so pg_query would know which one to use. So much data loss could have been prevented. So many good tuples… so much good data. Lost. Lost…

*sniff *