Alphabetical makes it so two databases with the same triggers have the same behavior. FIFO breaks that, because now it depends on trigger construction order (eg when dump/restoring) and is totally invisible to the user.

Additionally, modifying a trigger by drop/creating it would change behavior, unless you also drop/create every trigger (in the original order)

Thank you most important thing I learned today.

What is an example where the order of execution is required, not contrived or bad practise. Looking for a good use case

Easiest I can imagine is a user-facing id that gets incremented by trigger (e.g. select max(col)+1 — autoincrement/serial doesn’t guarantee contiguity, or even reasonable increments…).

And then any second trigger that relies on that value

Oh, I think it's probably bad practice to knowingly depend on that.

But I also think that it's unnecessarily problematic to make the order non-deterministic.

Not only what @setr answered but consider also that by having a consistent ruling you can actually design or alter the order of triggers just by naming them according to a specific scheme.

It just makes easier to understand what happens when triggers are invoked, without having to actually force specific cases by direct experimentation.

I did not even know that the standard prescribed a FIFO order, looks like a pretty bad idea to me, actually.

It means that the order they fire is imperative and determined by how you run your migrations.

The problem is that it doesn't leave you a great way to adjust order. It's just kinda weird.

(To be fair, table columns share this characteristic.)

> To be fair, table columns share this characteristic.

The table columns order is meaningless, but the triggers order is very relevant.

Table column order is not meaningless.

``` INSERT INTO foo SELECT * FROM bar ```

The harder problem however, is order in composite types.

Yeah, I do really recommend people not to do that sort of thing when they ask me.

Why was this down-voted? It is a good question. I thought exactly the same myself. And the reply from @setr is helpful. (Hat tip) I never thought about the impact of dump/restore!